Which Nuke to Commit: Atom vs Hydrogen vs MIRV in OpenFront

Short answer. Commit the smallest nuke that fully breaks your actual target: the 750,000 Atom for a single small or medium city, the 5,000,000 Hydrogen for one large capital you want gone in a single fall, and the 25,000,000-plus MIRV only when you must hit many targets or a wide front at once. Match footprint to target and pay the minimum that achieves the break; never replace a single heavy bomb with a spread.

The three weapons side by side

Before you can choose, you need the three weapons on one table so the trade is visible. Every number below is the v0.34.12 value from Config.ts, and “effective tiles” is the blast footprint with the outer ring counted at half strength, which is exactly how the detonation code applies it.

Weapon	Cost	Inner / outer radius	Effective tiles	Fleet speed	Breaks alliances	Best used when
Atom Bomb	750,000	12 / 30	~889	10	Yes	One small or medium city; cheap, repeatable pressure
Hydrogen Bomb	5,000,000	80 / 100	~34,225	10	Yes	One large capital or hub you want erased in one fall
MIRV	25,000,000 + 15,000,000 per launch	12 / 18 per warhead	up to 350 warheads	15 carrier / 22 warhead	No	Many targets at once, or a wide front

The inner disk destroys everything inside it on every tile. The ring out to the outer radius is a 50% coin flip per tile, so the ring contributes about half its geometric area. That is why the Atom is not just a “small circle”: it is a 452-tile solid core plus a 874-tile ring at half strength, landing roughly 889 effective tiles. The Hydrogen is the same shape scaled up: a 19,500-tile solid core plus a 58,500-tile ring at half strength, about 34,225 effective tiles. The MIRV is a different animal entirely. It is not one big circle at all; it is up to 350 separate small warheads, each with a 145-tile core and a 177-tile ring, aimed at independently chosen targets. The cost column is the one that matters most: the Atom is 750,000, the Hydrogen is 5,000,000, and a single MIRV launch is 25,000,000 with a further 15,000,000 charged per launch, so a full MIRV is more than 2.5 times the price of the Hydrogen on top of a base that is itself 33 times the Atom. If you spend the same gold on effective area, the Atom is dramatically cheaper per tile, which is the first and most important fact about this whole decision.

The clearest way to see the value of each weapon is gold spent per effective tile. The Atom delivers about 889 effective tiles for 750,000 gold, roughly 843 gold per tile; the Hydrogen delivers about 34,225 effective tiles for 5,000,000 gold, roughly 146 gold per tile; and a single MIRV warhead delivers about 322 effective tiles at a cost that, once you amortize the 25,000,000 base and 15,000,000 launch charges across its warheads, works out to tens of thousands of gold per tile. On pure destruction-per-gold the Hydrogen is the most efficient single bomb and the Atom is the cheapest way to buy a small amount of destruction you can afford to repeat. The MIRV is not efficient per tile at all: it is the most expensive thing you can fire, and it buys its value by hitting many targets at once and by being the fastest, hardest-to-intercept warhead on the board. That is why “cheapest bomb that does the job” is the right default for a single target, and why the MIRV is only ever the answer when the job is “many targets” or “through a dense SAM wall.” You can see the same weapon set and its exact costs on the Nuke & Missile Calculator, and the MIRV-specific mechanics, target generation, and the price ladder that sets the launch charge are covered in the MIRV guide and its timing breakdown in the MIRV Price Ladder.

Pick by target size and density

The first rule is target size. An nuke is a per-tile weapon, so the question is not “how big is the bomb” but “how many of the target’s tiles will my footprint actually hit, and what fraction of its troops does that delete.” The blast removes the target’s control of every tile it lands on and deletes troops using a curve that scales with how many of the target’s tiles you hit. The more of the target’s territory you cover in a single fall, the harder the troop penalty, because the per-tile damage compounds across the whole footprint.

For a small or medium city, the Atom is almost always enough. A city holding roughly a hundred to two hundred tiles sits well inside an Atom’s 889 effective tiles, so the bomb covers it many times over and the troop penalty is severe enough to break the defense. Paying 5,000,000 for a Hydrogen on that same city does not double your effect; it just wastes 4,250,000 of gold that you could have turned into a second Atom, an army, or structures. The Atom is the right default for anything you can fully cover, and because it is cheap you can afford to be wrong: a misjudged Atom costs you 750,000, while a misjudged Hydrogen costs you five times that and a missed opening.

For a large capital that is a thousand tiles or more, the math flips. The Atom covers only a fraction of it, deletes a smaller share of the defending troops, and the city simply rebuilds around the scar. The Hydrogen’s 34,225 effective tiles swallow the capital and everything around it in one fall, deletes a far larger share of the army, and removes the economic engine with the blast. That is exactly the situation the Hydrogen is priced for. The decision is not about which bomb is “stronger”; it is about matching footprint to the target so you do not pay the big-bomb price for a small-bomb result.

There is one case where the flip does not happen, and it is the one that surprises people. A city can be large in land but thin in troops: a sprawling 1,200-tile holding with a 600-troop militia. The Atom’s per-tile troop loss against that garrison is about 50 per hit tile (5 × 600 ÷ 1,200), and with a few hundred of those tiles inside the blast the militia is cut in half and the city falls to a follow-up land push. The Hydrogen would have been a five-million-dollar waste on a city whose army was already below the break line. So the tile column of the table is a starting point, not the whole rule: the real input is the ratio of troops to tiles, not the tile count by itself. When that ratio is high, a dense garrison, the smaller the city the worse the Atom’s low density performs and the more the Hydrogen’s density wins. When the ratio is low, a thin garrison, even a big city can be broken by an Atom and the Hydrogen is the wrong spend. Read the target’s actual troop count, not just its label, before you choose, because the ratio is the difference between a decisive strike and a wasted 750,000. Work through the real numbers on the Nuke & Missile Calculator, because the difference between “covers the target” and “covers a corner of the target” is the difference between a winning strike and a wasted 5,000,000.

Two worked scenarios with the numbers

Let’s put gold and tiles on two concrete situations so the rule is not abstract. In both, the target holds 1,000 troops, the blast removes the target’s control of the tiles it hits, and the troop penalty grows with the number of tiles covered.

Scenario one is a contested mid-game city holding 150 tiles with a 1,000-troop garrison, sitting near an alliance line you do not want to break. Your goal is to seize it this turn, not to erase a region. The Atom’s 889 effective tiles cover that 150-tile holding several times over, so the fall is decisive on the territory and the per-tile troop penalty is heavy enough to gut the garrison. You pay 750,000, you take the city, and the gold you save stays available for the follow-up push. The Hydrogen is strictly wrong here: its 34,225 effective tiles are more than you need, the 5,000,000 price is 4,250,000 more than the job requires, and because it is a dense single bomb it carries the alliance-break risk the MIRV would not, which is a real cost on a line you need to keep intact. The Atom wins on price, on fit, and on the diplomatic side effect.

Scenario two is a late-game enemy capital holding 1,500 tiles with a 5,000-troop army, the economic core of an opponent you need to end the game against, and you do not care about the tiles around it. The Atom covers only a corner, deletes a modest share of a 5,000-troop force, and the capital rebuilds. The Hydrogen’s 34,225 effective tiles cover the entire 1,500-tile capital many times over, so the troop penalty is severe on a 5,000-troop army and the region is simply removed. The 5,000,000 price is the right price for erasing an endgame engine in one fall, and because you are finished with diplomacy the alliance-break side effect costs you nothing. Now the MIRV case: if instead the enemy has a wide front of many mid-size cities and you cannot pick a single capital to matter, the MIRV is the weapon. Its up to 350 warheads spread across that front hit a large number of targets at once, which no single bomb can do, and the 25,000,000-plus price buys a board-wide pressure the two single bombs cannot match. The trade is that each individual warhead is a small 322 effective tiles, so any one city that you needed to erase completely is better hit by a concentrated single bomb.

There is a density nuance worth a sentence. Two cities of the same tile count can take the same bomb very differently depending on how their troops are distributed. The per-tile troop loss compounds across the tiles you hit, so a city whose garrison is concentrated in a tight cluster sits inside the inner disk of a single Atom and takes the full penalty, while a city that has spread its troops across a wide, thin ring may have most of its garrison outside your footprint and survive the fall with enough troops left to hold. That is why reading the target’s actual tile count and troop distribution, not just the city’s label, is the difference between a decisive strike and a wasted 750,000. Work through the real numbers on the Nuke & Missile Calculator, because the difference between “covers the target” and “covers a corner of the target” is the difference between a winning strike and a wasted 5,000,000, and the calculator will show you, tile by tile, which side of that line your chosen weapon lands on.

The SAM question: will they shoot it down

The second rule is defense density, and it applies to every weapon on the table. A missile is exposed to interception while it is inside a SAM’s range along its flight path, and a SAM is a real constraint, not a formality. The interceptor missile flies at speed 12, which is faster than the Atom and Hydrogen at speed 10, so once a SAM locks your missile the interceptor is closing on it, not chasing it. The launcher has a 90-tick cooldown and a range that grows with its level, starting around 70 tiles at level 1 and approaching 150 at high levels. A missile is targetable within a 150-tile radius of its path, so a SAM sitting within that band of your target, or along the arc of your launch, can spend its 90-tick cooldown trying to kill your bomb.

The way to read that is as a closing-speed race, and it is different for each weapon. Against the Atom and the Hydrogen, the interceptor at speed 12 closes on your speed-10 missile, so a SAM that locks early has the speed advantage and the whole 90-tick window to work, which is why the Atom and the Hydrogen are the two weapons a layered SAM defense is actually built to stop. The MIRV warhead is the exception: its warheads fly at speed 22, which is nearly twice the interceptor’s 12, so once a warhead is far enough out the interceptor is chasing, not closing, and a SAM that locked late or is at a level with a short range simply cannot catch it. That speed gap is the deepest reason the MIRV is the “through a dense SAM wall” tool: not because it is bigger, but because its warheads outrun the interceptors the wall throws at them.

The per-launch interception budget is also worth making explicit. Each SAM gets one 90-tick attempt per incoming missile, and its range is what determines whether it can reach the missile at all. A level-1 SAM with a 70-tile range only matters if the target sits within that 70-tile band of your missile’s path; a level-5 SAM near its 107-tile range covers a much wider arc and can reach missiles that a low-level SAM cannot. So the question “will they shoot it down” resolves into three checks before you launch: is there a SAM within 150 tiles of your target’s path, is that SAM levelled high enough to reach your missile’s arc, and does it have a free 90-tick cooldown when your missile is in range. If all three are yes, the Atom and the Hydrogen are genuinely at risk and you need either a different angle, a faster follow-up, or the MIRV’s outrunning warheads. The defender-side math, how many SAMs to place and what their range and cooldown actually cost, is in the SAM Launcher guide, and the endgame version of the interception question, when the whole board is under fire, is in the Doomsday Clock guide.

This also sets the practical launch rule. The single bombs, by contrast, are slow and deliberate, and a well-timed SAM can turn your 5,000,000 Hydrogen into a very expensive missile you will never see land, so before you commit a big single bomb read the SAMs on the flight path and time the launch for a cooldown gap or a lane the wall does not cover. If you would rather know exactly how many launchers to buy to stop a nuke, the defender-side math lives in the SAM Launcher guide, and what a nuke does to the land it hits, including the water-nuke case, is covered in the Land Combat and Water Nukes guides.

Pacing: the silo cannot spray nukes

The third rule is time, and it is easy to forget until your launch plan falls apart. A silo cannot fire two nukes back to back. After it launches, it is on a 90-tick cooldown before it can fire again, and a queue of stacked purchases fires as a trailing stream with at least one tick between each, never as a single overlapping burst. That 90-tick gap is about nine seconds of real time, and it changes how you plan a nuke sequence the same way a weapon cooldown changes a shooter’s plan.

Two consequences follow. First, a single heavy strike and a small barrage are different operations. One Atom is one launch, done. But if your plan is “hit three cities this turn,” you are really planning three launches spread across three 90-tick cooldowns, and the enemy sees each incoming missile and can react between them, moving troops, firing SAMs, or retreating. The value of spreading your gold across several smaller targets is partly eaten by the fact that they do not land together. Second, the MIRV is the opposite of a fast burst. Its carrier travels at 15, separates, and then releases up to 350 warheads, each flying at 22 to its own target. That is a long, extended delivery: a full MIRV does not arrive like a single bomb. It is a rolling wave over many seconds, which is exactly why it is a front-wide tool and why it is the right answer when you need pressure across a whole region but the wrong answer when you need one tile broken this turn.

The pacing also sets a hard ceiling on how much nuke pressure one silo can put out in a given window. At 90 ticks per launch, a single silo fires roughly one nuke every nine seconds, so a “stacked” plan of, say, four nukes actually takes about four 90-tick windows to fully land, during which the enemy gets four reactions. That means a single-silo nuke strategy is a series of timed strikes you interleave with your normal economy and army work, not a one-button burst. If your plan depends on timing a single decisive fall, an Atom or a Hydrogen is the tool because it lands in one window. If your plan is sustained board-wide pressure, the MIRV’s long delivery is the feature, not a bug: its warheads keep arriving over many seconds, so the pressure does not stop when the carrier splits. You can also split the pressure across more than one silo if you have built a second, which is the only way to fire two nukes that land in the same window, and it is worth the silo cost when the target set is big enough to justify two 1.5M silos. The endgame shape of that sustained pressure, and what to do when a MIRV is in play, is the subject of the Doomsday Clock and the post-MIRV recovery guides.

The alliance cost of each weapon

The fourth rule is diplomatic, and it is the one that surprises players because it is in the detonation code and not on any button. Atom and Hydrogen break alliances when they hit hard enough. The code checks, for each nearby ally, the weighted number of the ally’s tiles the blast covers, counting the inner disk at full weight and the ring at half weight, and if that weighted total reaches 100 it severs the alliance with that player and rejects any pending request. In plain terms: if your Atom or Hydrogen lands such that it hits roughly a hundred weighted tiles of an ally’s land, you will not just destroy the enemy city, you will also break your alliance with the player who owns the tiles next to it.

The MIRV warheads are exempt. The code returns early for them and does not run the alliance check, so a full MIRV spread can hit across a board full of allies without severing any of them. That is a decisive advantage in the specific situation where you need to hit a target that sits right next to someone you are allied with, or where you are allied to several players whose territory your big-bomb footprint would sweep up. A dense Atom or Hydrogen aimed at a city on an alliance line is a gamble that you might break the alliance the moment it lands; the MIRV is the only weapon on the table that lets you hit that line and keep the relationships intact. The flip side is that the alliance-break risk also cuts against you when it is your own line you are protecting. If your target is close to an ally you cannot afford to lose, a smaller Atom aimed more precisely, or the alliance-exempt MIRV, is safer than a Hydrogen whose 34,225 effective tiles sweep a wide band and are very likely to cross the 100 weighted-tile line over a nearby ally.

The 100 weighted-tile threshold is the number to keep in your head, and it is easier to trip than it looks. Weighted tiles count the inner disk at full weight and the ring at half weight, so the Atom’s 452 solid core tiles alone already far exceed 100 on their own, which means any Atom whose core overlaps an ally’s land by even a modest band will break the alliance if the overlap is roughly a hundred weighted tiles or more. The Hydrogen’s core is 19,500 tiles, so it breaks the alliance with anyone it touches unless the ally’s territory is essentially outside the entire blast. That is why the alliance question is really a placement question: it is not “will this bomb break an alliance” but “is the target close enough to an ally’s land that the footprint, at full or half weight, crosses a hundred weighted tiles over that ally.” Before you commit a dense single bomb near an alliance line, draw the blast circle and check the overlap against the nearest ally’s tiles. If you are in doubt, the two safe moves are to shift the target or the aim so the footprint clears the ally, or to use the MIRV, whose warheads skip the check entirely. The full decision space of when to be allied at all, and what breaking an alliance costs you on a board, is laid out in the Nation Alliance Decisions guide, and the no-alliances mode, where this entire rule does not apply, is described in the No Alliances Mode guide.

When the plan fails and how to recover

Every weapon on the table can miss in a way that is specific to it, and the recovery is different each time, so plan the failure before you fire. The Atom can fail by being too small: you cover a fraction of a larger target, delete too few troops, and the city rebuilds around the scar while your 750,000 is gone and the enemy now knows you are nuke-happy. The recovery is not to throw a bigger bomb at the same problem but to re-evaluate whether the target was actually an Atom target; if it is a thousand-tile city, the 750,000 was the wrong tool and the correct move is to hold the 5,000,000 for a moment when the capital is vulnerable, or to break it with a conventional push first so the Atom has a smaller target to finish.

The Hydrogen can fail by being intercepted: the 5,000,000 missile is slow at speed 10, a SAM on the flight path spends its 90-tick cooldown closing on it at speed 12, and your biggest single investment turns into a missile that never lands while the enemy keeps its capital and its army and now knows your exact target and timing. The recovery is to read the SAM line next time and either launch into a cooldown gap, choose a flight path the launch arc gives you, or accept that a heavily SAM-defended capital is not a one-bomb problem and is better attacked by the faster, harder-to-intercept MIRV warheads. The MIRV can fail in the opposite direction: it is spread, not concentration, so if your real goal was to erase one specific capital, 350 warheads of 322 effective tiles each across a board will not do what a single 34,225-tile Hydrogen would, and you have spent 25,000,000-plus on a spread that did not break the one thing that mattered. The recovery is to keep a single dense bomb in reserve for the one target that truly needs erasing and use the MIRV only for the wide-front pressure it is actually good at. The cross-weapon recovery, the shape of the endgame when a nuke has landed, and the timing of the decisive final strike are all covered in the Doomsday Clock guide, so the recovery plan for a bad nuke lands on the same page as the plan for winning the last few minutes of the match.

Mode, map, and settings that change the answer

The answer above is the default for a standard match on a standard map, but several settings and map shapes change which weapon wins, and you should check them before you commit gold. In infinite-troops mode the troop-loss curve is largely irrelevant, because the target simply regrows to a huge cap, so the weapon choice collapses to pure tile destruction and the footprint that removes the most territory per gold is the answer; that favors the cheaper, repeatable Atom for grinding territory and reserves the Hydrogen for a single decisive removal of a region. On compact maps every nuke is a larger share of the whole board, so the Hydrogen’s 34,225 effective tiles can be a quarter or more of a small map and the MIRV’s 350-warhead spread can blanket the entire playing area; on those boards the bigger weapons are more powerful and the MIRV’s wide front becomes an overwhelming endgame tool. On large maps the opposite holds: the Hydrogen covers a smaller share of the board, the Atom’s coverage is less of a fraction, and the MIRV’s spread is what finally scales to a front of many cities.

Two settings change the answer in ways that are easy to miss. The first is the map-size and compact-mode setting, which shrinks the playable area and with it the relative power of every nuke footprint; on a small board the Hydrogen’s footprint is a much larger fraction of the whole, so the cost per board-tile destroyed drops and the Hydrogen becomes the efficient endgame removal even earlier, while on a large board the same Hydrogen is a smaller fraction and the MIRV’s many warheads are the only thing that scales to the front. The second is the water-nuke setting, which changes the blast boundary from a clean ring to a smoothed, irregular edge; that matters most for the Atom’s tight footprint, because the Atom’s 452 core tiles and 874 ring tiles are a much smaller absolute area than the Hydrogen’s, so a smoothed edge removes a bigger share of its effective coverage and makes the Atom slightly less efficient than the ring math above assumes, which is the reason a water-map Atom can under-perform the numbers and why you should check the actual blast on the map rather than trusting the idealized ring. Read these before you commit, because the weapon that is correct on a standard board can be the wrong call on a compact or infinite-troops match, and the 5,000,000 or 25,000,000 you spend is the same gold either way. The Doomsday Clock guide covers the endgame shape of these decisions in the last hours of a match, and the post-MIRV recovery guide covers what happens to your own board when a MIRV lands.