Factorio Power Plant Calculator

Q: How many solar panels do I need for 1 MW on Nauvis?

24 normal-quality panels. Each panel averages 42 kW over the 420-second day-night cycle, so 1000 kW / 42 kW = 23.8, rounded up to 24. Pair with about 24 accumulators : the solver uses the 119-second night-balance model (1000 kW × 119 s / 5 MJ = 23.8, rounded up to 24), which lands a touch above the looser 0.84-per-panel shorthand.

Q: What is the optimal nuclear reactor layout?

2xN. Each reactor in a 2-wide row sees 3 active neighbours (one across, one on each side, with end reactors slightly less), pushing effective thermal output to 40 × 4 = 160 MW per reactor. Square grids reach 4 neighbours for interior reactors but the corners pull the average down and the access lanes for fuel-cell inserters become awkward. 2xN is the megabase standard.

Q: How many fusion generators per reactor in Space Age?

2 to 12. With 0 neighbour bonus, 1 reactor (100 MW plasma) feeds 2 generators (50 MW each). With the 5-neighbour cap engaged, 1 reactor (600 MW plasma) feeds 12 generators. Fluoroketone consumption is constant at 4 cold/sec per reactor and 2 hot/sec per generator, so stacking neighbours is pure-upside electricity.

Q: Why does fusion use less fluoroketone with neighbour bonus?

It does not. The fluoroketone consumption per reactor is fixed at 4 cold/sec regardless of neighbour count . What changes is the plasma output: 100 MW for an isolated reactor, 600 MW for a 5-neighbour reactor — same fluid loop, 6× the electricity. This is the design point of the fusion endgame: neighbour stacking is free leverage.

Size your Factorio power plant in MW. Boilers + steam engines for early game, solar panels + accumulators for renewable Nauvis builds, nuclear reactors with neighbour bonus for megabase density, fusion plants for Aquilo. Covers the base game and Space Age quality tiers.

Updated: May 15, 2026

Factorio power plant calculator. Boilers, panels, reactors, and fusion plants for any MW target.

Enter your target load in MW and this Factorio power plant calculator returns the exact boilers, panels, reactors, or fusion generators you need. Covers the base game, Space Age planets, neighbour bonus, and every quality tier.

What is a Factorio power plant calculator?

The moment your grid can't carry peak load, the whole base browns out: smelters stall, inserters freeze, and the laser turrets drop offline right as a biter wave hits the wall. Tell this calculator how many MW you need and it returns the exact building count across the four generation modes the game ships: steam (boilers + steam engines), solar (panels + accumulators), nuclear (reactors + heat exchangers + steam turbines), and fusion (Space Age reactors + generators on Aquilo). It is the power-supply twin of a production calculator: production tells you the megawatts you draw, this tool tells you the megawatts you build.

This calculator does the planet-specific maths the production calc deliberately skips. Nauvis solar averages 42 kW per panel over a 420-second day-night cycle (peak 60 kW × 70 percent). Vulcanus has a 90-second cycle with only 9 seconds of darkness, so the average jumps to 168 kW (peak 240) and accumulators become near-optional. Fulgora's atmosphere is 20 percent of Nauvis, so solar averages a paltry 8.4 kW per panel — lightning collectors carry the load instead. Gleba averages 21 kW per panel and has no uranium, so nuclear is unavailable; rocket-fuel heating towers feeding the steam pipeline are the canonical answer. Aquilo gets 0.42 kW per panel and forces fusion. The nuclear branch models the neighbour bonus exactly (+100 percent per adjacent active reactor, so a 2xN row averages 3 neighbours = 4x effective thermal per reactor); the fusion branch caps neighbours at 5, scaling plasma output up to 6x. Every number above is verified against the Factorio Wiki on 2026-05-15.

How to use the power plant calculator (and do the math yourself)

Using the tool is one input on the default screen. Doing it by hand takes five formulas — both are below.

Using the tool

1. Enter your target electricity demand (defaults to 5 MW). The unit selector switches between kW, MW, and GW.

2. Pick a game mode (base game or Space Age) and a planet (defaults to Nauvis). In Space Age, pick a quality tier (normal, uncommon, rare, epic, legendary).

3. Read the hero result for the recommended mode. The comparison grid below shows all four modes side-by-side with primary count, secondary count, footprint, fuel or fluid rate, and feasibility per planet.

4. Drill into a mode tab to override defaults: steam fuel (coal, solid fuel, rocket fuel), nuclear layout (isolated, 1xN, 2xN, square), or fusion neighbour count (0 to 5).

By hand

1. Steam: 1 boiler produces 1.8 MW thermal, feeds 2 steam engines at 900 kW each. For X MW, build ceil(X / 0.9) engines and ceil(engines / 2) boilers. Coal at 4 MJ per item burns at (boilers × 1.8 MJ/s) / 4 MJ = boilers × 0.45 coal/sec.

2. Solar: per-panel average is 42 kW on Nauvis, 168 kW on Vulcanus, 21 kW on Gleba, 8.4 kW on Fulgora, 0.42 kW on Aquilo. Multiply by the quality factor (1.0, 1.3, 1.6, 1.9, 2.5). Panels = ceil(X / avg). Accumulator ratio is 0.84 per panel on Nauvis (5 MJ × 60 sec / 42 kW = 7.14 panels per accumulator-night-budget) but throughput-bound at higher qualities.

3. Nuclear: 1 isolated reactor outputs 40 MW thermal. Each heat exchanger consumes 10 MW thermal and produces 103 steam/s; each steam turbine outputs 5.82 MW and consumes 60 steam/s, so 1.72 turbines per exchanger. A 2xN row gives each reactor 3 active neighbours, multiplying base thermal by 4 (= 160 MW per reactor). Reactors = ceil(thermal_demand / 160,000 kW).

4. Fusion (Space Age, Aquilo): 1 reactor outputs 100 MW plasma at normal quality, 1 generator outputs 50 MW. Each generator consumes 2 hot fluoroketone/sec; each reactor consumes 4 cold fluoroketone/sec (constant regardless of neighbour bonus). With N=5 neighbours the reactor scales to 600 MW plasma, feeding 12 generators.

Power plant sizing — the four generation formulas

P_{\text{supplied}} = n_{\text{primary}} \cdot P_{\text{primary}} \cdot q(t) \cdot (1 + N \cdot b)

$P_{\text{supplied}}$ = Total electric power supplied to the grid, in kW.
$n_{\text{primary}}$ = Primary generator count (boilers for steam, panels for solar, reactors for nuclear or fusion).
$P_{\text{primary}}$ = Base output per primary generator at the chosen planet (kW).
$q(t)$ = Quality scaling factor: 1.0 (normal), 1.3 (uncommon), 1.6 (rare), 1.9 (epic), 2.5 (legendary).
$N$ = Active neighbour count for nuclear or fusion reactors (0 if isolated, up to 5 for fusion, up to 4 for nuclear in a square).
$b$ = Neighbour bonus per link: 1.0 (= +100% per neighbour, identical for nuclear and fusion).

Steam and solar do not benefit from neighbour bonus (N = 0), so the formula collapses to P = n · P_primary · q(t). Nuclear is where the +100%-per-neighbour rule matters: in a 2xN row, an interior reactor sees 3 active neighbours and outputs 40 × (1 + 3) = 160 MW thermal, four times the isolated baseline. Fusion lets you stack up to 5 neighbours per reactor (the rest of the 8 connection ports get crowded out), giving a maximum plasma output of 100 × 6 = 600 MW from a single reactor — enough to feed 12 generators at 50 MW each. Fuel and fluid consumption do NOT scale with the neighbour bonus: a 5-neighbour fusion reactor consumes the same 4 cold fluoroketone/sec as an isolated one, which is why stacking neighbours is the highest-leverage move on Aquilo.

Worked examples with the full math

5 MW Nauvis starter base on steam

Target: 5 MW = 5000 kW. Steam engines = ceil(5000 / 900) = 6 engines. Boilers = ceil(6 / 2) = 3 boilers. Supplied = 6 × 900 = 5.4 MW (8 percent headroom). Coal consumption: 3 × 1.8 MW / 4 MJ per coal = 1.35 coal/sec = 81 coal/minute. Footprint: 3 × 6 + 6 × 15 = 108 tiles. This is the canonical pre-blue-circuit power block.

100 MW Nauvis solar farm (normal quality)

Target: 100 MW = 100,000 kW. Average panel output on Nauvis = 42 kW. Panels = ceil(100,000 / 42) = 2381 solar panels. Accumulators sized by the 119-second Nauvis night-demand model the solver uses: ceil(max(100,000 × 119 / (5 × 1000), 100,000 / 300)) = ceil(max(2380, 334)) = 2380 accumulators. The community-canonical 0.84 panels:accumulator shorthand gives ceil(2381 × 0.84) = 2001 as a slightly looser approximation; the calculator uses the more precise 119-second night-balance derivation. Footprint: 2381 × 9 + 2380 × 4 = 30,949 tiles. For reference, 100 MW of nuclear (2xN) fits in about 361 tiles — solar is roughly 86× the area but pays no fuel cost ever.

1 GW Space Age nuclear on Nauvis (2xN layout)

Target: 1 GW = 1,000,000 kW. Steam turbines = ceil(1,000,000 / 5820) = 172 turbines. Heat exchangers = ceil(172 × 60 / 103.09) = 101 exchangers. Effective per-reactor thermal (2xN, 3 neighbours) = 40 × 4 = 160 MW. Reactors = ceil(101 × 10,000 / 160,000) = 7 reactors (one 2x4 row with one position empty). Fuel cells: 7 reactors × (1 cell / 200 sec) × 60 = 2.1 fuel cells per minute. The 7-reactor arrangement is the standard 1 GW megabase block.

300 MW Vulcanus solar (legendary quality, no accumulators)

Target: 300 MW = 300,000 kW. Average panel output on Vulcanus = 168 kW base × 2.5 (legendary) = 420 kW per panel. Panels = ceil(300,000 / 420) = 715 legendary panels. Vulcanus night lasts 9 seconds out of a 90-second cycle, so practical builds ship a few accumulators for the brief darkness but you do NOT size them by the Nauvis 0.84-per-panel ratio. Footprint: 715 × 9 ≈ 6435 tiles — roughly a quarter of the Nauvis equivalent because each panel is 4× stronger.

600 MW Aquilo fusion plant (N=5 neighbours, normal quality)

Target: 600 MW = 600,000 kW. Generators = ceil(600,000 / 50,000) = 12 fusion generators. Effective per-reactor output at N=5 = 100 × (1 + 5) = 600 MW plasma. Reactor count = ceil(12 × 50,000 / 600,000) = 1 reactor. Fluid loop: 12 generators × 2 hot fluoroketone/sec = 24 hot fluoroketone/sec, and the reactor consumes 4 cold fluoroketone/sec regardless of neighbours — closed-loop, so the cryogenic plant only needs to sustain the throughput. This is why 1:12 reactor-to-generator at full neighbour stack is the canonical Aquilo build.

Quality table: panels per MW on Nauvis

Same 1 MW target across every quality tier of solar panel. Normal (42 kW): 24 panels. Uncommon (54.6 kW): 19. Rare (67.2 kW): 15. Epic (79.8 kW): 13. Legendary (105 kW): 10 panels. Legendary panels cost more than 2.5× the materials of normal panels, so they only pay off if the footprint is the limiting factor (Aquilo platform, expedition outpost, late-game Fulgora island). For the average Nauvis megabase, normal panels are still optimal by labour cost.

Tips and gotchas every Factorio engineer should know

Solar panel output averages 70 percent of peak over a full day-night cycle on every planet. The wiki's per-planet column is peak; the calculator's per-planet column is average. Nauvis 60 / 42, Vulcanus 240 / 168, Fulgora 12 / 8.4, Gleba 30 / 21, Aquilo 0.6 / 0.42 kW. Always design against the average.
Accumulators throughput-cap at 300 kW base discharge. Quality scales capacity 1.0/2.0/3.0/4.0/6.0× but discharge rate only 1.0/1.3/1.6/1.9/2.5× — the mismatch means legendary accumulators are capacity-rich but throughput-poor relative to their MJ rating. On Vulcanus the short night makes the throughput limit dominate; on Nauvis the long night makes capacity dominate.
The 25:21 (or 0.84:1) panel-to-accumulator ratio is for Nauvis at normal quality only. Vulcanus needs about 0.73 per panel; on Gleba and Fulgora the standard accumulator math no longer applies because lightning collectors and rocket-fuel heating towers cover the load.
Gleba has no uranium, so the calculator disables nuclear there. The community-standard answer is rocket-fuel heating towers (250 percent fuel efficiency) feeding the standard heat-exchanger and turbine pipeline. Plug rocket fuel demand into the production calc and feed the resulting MW back into this calculator on Nauvis steam mode for a parity build.
Neighbour bonus is +100 percent per adjacent active reactor for BOTH nuclear and fusion. A 2xN nuclear row averages 3 neighbours per reactor (4x effective thermal). A fusion reactor with 5 connected neighbours hits the cap at 6x base plasma. Beyond 2xN, custom shapes give diminishing layout returns because you also need access lanes for fuel-cell inserters.
Fusion generators consume 2 hot fluoroketone/sec; fusion reactors consume 4 cold fluoroketone/sec — regardless of neighbour bonus. This is the most important nuance on Aquilo: stacking neighbours multiplies free electricity but does NOT increase the cryogenic-plant throughput you must supply. One cryo plant per reactor is the universal rule.
If a result looks wrong, drill into the mode tab and read every multiplier. Steam supplied power is always engines × 0.9 MW; nuclear supplied power is always turbines × 5.82 MW; fusion supplied power is always generators × 50 MW × quality. Reactor and exchanger counts are derived from those primaries, never the other way around.

Factorio power plant calculator — frequently asked questions

How many solar panels do I need for 1 MW on Nauvis?

24 normal-quality panels. Each panel averages 42 kW over the 420-second day-night cycle, so 1000 kW / 42 kW = 23.8, rounded up to 24. Pair with about 24 accumulators: the solver uses the 119-second night-balance model (1000 kW × 119 s / 5 MJ = 23.8, rounded up to 24), which lands a touch above the looser 0.84-per-panel shorthand.

What is the optimal nuclear reactor layout?

2xN. Each reactor in a 2-wide row sees 3 active neighbours (one across, one on each side, with end reactors slightly less), pushing effective thermal output to 40 × 4 = 160 MW per reactor. Square grids reach 4 neighbours for interior reactors but the corners pull the average down and the access lanes for fuel-cell inserters become awkward. 2xN is the megabase standard.

How many fusion generators per reactor in Space Age?

2 to 12. With 0 neighbour bonus, 1 reactor (100 MW plasma) feeds 2 generators (50 MW each). With the 5-neighbour cap engaged, 1 reactor (600 MW plasma) feeds 12 generators. Fluoroketone consumption is constant at 4 cold/sec per reactor and 2 hot/sec per generator, so stacking neighbours is pure-upside electricity.

Is this Factorio power calculator free?

Yes — free, no account, no login. Everything runs in your browser; no data leaves your device. The same applies to the linked production calculator.

Does the calculator support the Space Age DLC?

Yes. The game-mode toggle switches between Factorio 2.0 (base) and Space Age, which unlocks fusion mode, all four extraplanetary maps (Vulcanus, Fulgora, Gleba, Aquilo), and the five-tier quality system. Nuclear is still available in Space Age except on Gleba (no uranium) and Aquilo (cryogenic ambient defeats heat pipes).

How does quality affect power generation?

Quality scales output linearly: 1.0 / 1.3 / 1.6 / 1.9 / 2.5× for normal, uncommon, rare, epic, legendary. Solar panels, accumulators, fusion reactors, and fusion generators all scale. Steam turbines, heat exchangers, and nuclear reactors have quality variants in the wiki too (legendary turbine = 14.55 MW, legendary exchanger = 25 MW). The base-game pre-DLC steam pipeline is the only non-scaling case.

Why does fusion use less fluoroketone with neighbour bonus?

It does not. The fluoroketone consumption per reactor is fixed at 4 cold/sec regardless of neighbour count. What changes is the plasma output: 100 MW for an isolated reactor, 600 MW for a 5-neighbour reactor — same fluid loop, 6× the electricity. This is the design point of the fusion endgame: neighbour stacking is free leverage.

Can I power Gleba with nuclear?

No. Gleba has no uranium ore, so nuclear fuel cells cannot be crafted on-planet. The community-standard answer is rocket-fuel heating towers (Space Age building, 250 percent fuel efficiency) feeding the standard heat-exchanger and turbine pipeline. Rocket fuel is cheap on Gleba because jellynut and yumako pulp spoil otherwise, so jellynut-burner power is effectively free recycling.

How accurate are the recommendations?

All numbers verified against the public Factorio Wiki on 2026-05-15: boiler 1.8 MW + 60 steam/s, steam engine 900 kW + 30 steam/s, solar panel 42 kW avg on Nauvis, accumulator 5 MJ + 300 kW, nuclear reactor 40 MW + 200-sec fuel cell, heat exchanger 10 MW + 103 steam/s, steam turbine 5.82 MW + 60 steam/s, fusion reactor 100 MW + 4 fluoroketone/s, fusion generator 50 MW + 2 fluoroketone/s. The 0.84 accumulator ratio comes from forum.factorio.com t=5594 and t=119040. Quality multipliers from wiki/Quality.

How do I link this with the production calculator?

Solve your production plan first, read the total power draw, then jump to the power plant calculator with the `?tkw=` URL parameter pre-filled. Example: a 200 MW iron-plate megabase from the production calc opens this page with the target set to 200,000 kW. Build, copy the result, blueprint it. Round-trip is two clicks.

Can I share the result with a teammate?

Yes. Every input (target, planet, quality, layout, fuel) is encoded in the URL, so "Copy link" produces a permalink that reproduces the exact scenario. Versioned schema so older links continue to resolve after updates.

Does the calculator work on mobile?

Yes. Inputs stack vertically on narrow screens, the comparison grid becomes a swipeable card stack, and the formula panels collapse to accordions. Most Factorio power calculators are desktop-only; this one is not.

Glossary of Factorio power-plant terms

Neighbour bonus

+100 percent per adjacent active reactor, applied to BOTH nuclear and fusion. A 2xN nuclear row averages 3 neighbours per reactor (= 4x effective thermal). A fusion reactor caps at 5 active neighbours (= 6x base plasma).

Quality tier

Space Age 5-tier rarity for buildings: normal, uncommon, rare, epic, legendary. Output multipliers are 1.0, 1.3, 1.6, 1.9, 2.5× base. Accumulator capacity follows a different scale (1.0, 2.0, 3.0, 4.0, 6.0× MJ) but discharge rate uses the 1.0–2.5× scale.

Average panel output

Solar power averaged over a full day-night cycle, always 70 percent of peak. Nauvis 42 kW, Vulcanus 168 kW, Gleba 21 kW, Fulgora 8.4 kW, Aquilo 0.42 kW (all at normal quality).

Accumulator throughput

Maximum charge/discharge rate per accumulator: 300 kW at normal quality, 750 kW at legendary. Scales 1.0/1.3/1.6/1.9/2.5× with quality, while capacity scales 1.0/2.0/3.0/4.0/6.0× — the mismatch becomes the bottleneck at higher qualities.

0.84 ratio

The canonical Nauvis accumulator-per-panel ratio: 42 kW × 100 sec / 5 MJ = 0.84 (precise value 0.84672). Practical builds use 25:21 (panels:accumulators). Only applies to Nauvis at normal quality.

2xN reactor layout

Two parallel reactor rows of arbitrary length N. Each interior reactor has 3 active neighbours; total array output ~160(n - 1) MW for n total reactors. The community-standard megabase pattern because it gives 4x effective thermal while keeping fuel-cell inserter lanes accessible.

Fluoroketone loop

Aquilo's closed-loop coolant for fusion. Cryogenic plant produces cold fluoroketone (4/sec per reactor); reactor returns hot fluoroketone (4/sec); generator consumes 2 hot/sec, exhausts cold back to the cryo plant. Throughput is fixed regardless of neighbour bonus.

Heating tower

Space Age building (Gleba unlock) burning any fuel at 250 percent efficiency to feed the heat-pipe + heat-exchanger pipeline. Replaces nuclear on Gleba; rocket fuel and spoilage are the standard inputs.

Peak vs. average output

Solar peak is what one panel produces at noon; solar average is what it produces averaged across one day-night cycle. Always size against average; the accumulators cover the peak-average gap.

Sources & References

Content verified by the Smart Calculators Team