Beacons and modules: effects, the profile array, and beaconed builds
Modules modify the machines they are placed in. Beacons transmit those modifications to nearby machines without occupying the machine's own slots. Together they are the primary tool for squeezing more throughput out of a fixed footprint, and the interaction between them is where most of the interesting arithmetic lives.
Figures computed from game version 2.1.12, updated 2026-08-22.
What a beacon does
A beacon is a 2-slot machine that holds modules and transmits their effects to every machine within its supply area. The supply area extends 3 tiles from the beacon in every direction, covering a square region 7 tiles on each side. Machines inside that area receive the beacon's module effects, scaled by the beacon's distribution effectivity and by a profile factor that depends on how many beacons cover the same machine.
The beacon itself draws 480.0 kW continuously, regardless of whether any machine is in range. It does not craft anything and does not accept productivity modules; only speed, efficiency (consumption), and pollution effects are transmitted. A beacon with no modules still draws power, so empty beacons should be avoided.
Distribution effectivity by quality
The base beacon has a distribution effectivity of 1.5. This means every module effect transmitted by the beacon is multiplied by 1.5 before reaching the machine. A speed module 3 that gives +50% speed when placed directly in a machine gives +75% speed when transmitted through a normal-quality beacon.
Higher quality beacons gain 0.2 additional effectivity per quality tier. The five playable qualities and their resulting effectivity values are computed below from the beacon prototype and the quality list.
| Quality | Quality level | Distribution effectivity | Speed module 3 transmitted |
|---|---|---|---|
| Normal | 0 | 1.5 | +75% |
| Uncommon | 1 | 1.7 | +85% |
| Rare | 2 | 1.9 | +95% |
| Epic | 3 | 2.1 | +105% |
| Legendary | 5 | 2.3 | +115.0% |
A legendary beacon at 2.3 effectivity transmits a speed module 3 at +115.0% speed bonus, compared to +75% for a normal beacon. That is a 53.3% increase in transmitted effect per module, before counting the profile sharing factor discussed below.
The profile array: the data no other site publishes
The beacon prototype in data/2.1/machines.json contains a
field called profile: an array of 100 numbers, all
of which are nonzero. This array describes how a beacon's transmitted
effect changes when multiple beacons cover the same machine. It is the
single most unusual piece of data in the beacon prototype, and it is not
documented in the game's tooltip or in most community guides.
The array is zero-indexed. When exactly one beacon covers a machine, the
machine uses profile[0], which is 1. When two
beacons cover the same machine, each uses profile[1] =
0.7071. When eight beacons cover a machine, each uses
profile[7] = 0.3535. The factor decreases
as more beacons share the coverage, which is the game's mechanism for
imposing diminishing returns on stacking beacons.
| Beacons covering machine | Profile index | Profile factor | Collective effect (N x factor) |
|---|---|---|---|
| 1 | 0 | 1.0000 | 1.0000 |
| 2 | 1 | 0.7071 | 1.4142 |
| 4 | 3 | 0.5000 | 2.0000 |
| 8 | 7 | 0.3535 | 2.8280 |
| 12 | 11 | 0.2886 | 3.4632 |
| 16 | 15 | 0.2500 | 4.0000 |
The collective effect column reveals the scaling law. With one beacon
the collective multiplier is 1.0000. With four beacons it is
1.4142, and with eight it is
2.8280. These are not the beacon
counts themselves; they are the square roots of the beacon counts (to
four decimal places, sqrt(2) = 1.4142, sqrt(4) =
2.0000, sqrt(8) = 2.8284). The
profile array follows the formula 1 / sqrt(N) where N is
the number of beacons covering the machine.
This means that doubling the number of beacons around a machine does not double the effect; it multiplies it by the square root of 2, roughly 1.414. Four beacons deliver twice the effect of one; eight deliver 2.83 times; sixteen deliver four times. The beacon power cost scales linearly (each beacon always draws 480.0 kW), so the power per unit of delivered effect grows as the square root of the beacon count. Eight beacons use eight times the power of one but deliver only 2.83 times the module effect.
The full array extends to 100 entries, but in practice no machine is covered by more than a dozen beacons in a viable layout. The supply area of 3 tiles means beacons must be placed adjacent to or one tile away from the machine they cover, and the maximum number that can physically reach a single assembling machine is around twelve. The tail of the profile exists for edge cases and modded builds.
All twelve modules
There are four module categories, each with three tiers: speed,
efficiency, productivity, and quality. Every effect value below is read
from data/2.1/items.json. Positive values are bonuses;
negative values are penalties.
Speed modules
| Module | Speed | Power consumption | Quality |
|---|---|---|---|
| Speed Module | +20% | +50% | -1% |
| Speed Module 2 | +30% | +60% | -1.5% |
| Speed Module 3 | +50% | +70% | -2.5% |
Speed modules are the straightforward throughput option. Speed module 3 gives +50% speed for +70% more power. The speed bonus applies directly to the machine's crafting speed; the power penalty multiplies its energy draw. Speed modules also carry a small quality penalty, reducing the chance of higher-quality output.
Efficiency modules
| Module | Power consumption |
|---|---|
| Efficiency Module | -30% |
| Efficiency Module 2 | -40% |
| Efficiency Module 3 | -50% |
Efficiency modules reduce power consumption with no downside. They are the only module category with no penalty. Efficiency module 3 reduces power draw by 50%. They are less useful in beaconed builds (where the beacon itself draws a fixed 480.0 kW regardless) but are valuable for reducing the power cost of mining drills and electric furnaces in large arrays.
Productivity modules
| Module | Productivity | Speed | Power consumption | Pollution |
|---|---|---|---|---|
| Productivity Module | +4% | -5% | +40% | +5% |
| Productivity Module 2 | +6% | -10% | +60% | +7.0% |
| Productivity Module 3 | +10% | -15% | +80% | +10% |
Productivity modules are the only module that cannot be placed in a beacon. They must go directly into the machine. Each productivity point gives a chance to produce an extra set of outputs for free, at the cost of speed, power, and pollution. Productivity module 3 gives +10% productivity, -15% speed, +80% power, and +10% pollution. The free outputs compound: a machine with four productivity module 3s has +40% productivity, meaning roughly 40% more output per input over time.
Productivity modules only work in machines whose recipes allow them. Intermediate products such as plates, circuits, gears, and science packs are productivity-allowed; final products like assemblers and belts are not. The recipe flag that controls this is in the recipe data.
Quality modules
| Module | Quality | Speed |
|---|---|---|
| Quality Module | +1% | -5% |
| Quality Module 2 | +2% | -5% |
| Quality Module 3 | +2.5% | -5% |
Quality modules increase the probability that a craft produces a higher-quality result, at a 5% speed penalty. Quality module 3 gives +2.5% quality chance per module. Like productivity modules, quality modules cannot be transmitted by beacons; they go directly in the machine. The quality system is a 2.0 feature where higher-quality items and machines have better stats.
Worked example: 8 beacons around an assembling machine 3
This example puts 8 beacons around a single assembling machine 3. Each beacon holds 2 speed module 3s. The AM3 holds 4 speed module 3s in its own slots. All numbers below are computed in frontmatter from the prototype data.
| Parameter | Value | Source |
|---|---|---|
| Beacons | 8 | Layout choice |
| Profile index | 7 | 8 beacons - 1 |
| Profile factor | 0.3535 | profile[7] in beacon prototype |
| Distribution effectivity (normal) | 1.5 | beacon.distribution_effectivity |
| Speed per beacon (2 x SM3) | +100% | 2 x +50% |
| Power per beacon (2 x SM3) | +140% | 2 x +70% |
| Transmitted speed per beacon | +53.0% | +100% x 1.5 x 0.3535 |
| Total beacon speed bonus | +424.2% | 8 x +53.0% |
| AM3 own speed bonus (4 x SM3) | +200% | 4 x +50% |
| Final speed multiplier | 7.242 | 1 + beacon + own |
| AM3 base crafting speed | 1.25 | assembling-machine-3.crafting_speed |
| Effective crafting speed | 9.05 crafts/s | 1.25 x 7.242 |
The AM3 runs at 9.05 crafts per second for a recipe with a 1-second craft time. That is 7.2 times its unmoduled speed of 1.25. For a 0.5-second recipe such as electronic circuits, the same machine produces 18.1 items per second. The eight beacons contribute +424.2% of the speed bonus, while the AM3's own four modules contribute +200%. Even with the profile diminishing returns, the beacons deliver more than twice the effect of the machine's own slots.
Power draw
| Component | Base power | Multiplier | Final power |
|---|---|---|---|
| AM3 (machine) | 375.0 kW | x 9.74 | 3.65 MW |
| 8 beacons | 8 x 480.0 kW | - | 3.84 MW |
| Total | - | - | 7.49 MW |
The beacons themselves consume 3.84 MW, which is actually slightly more than the 3.65 MW drawn by the heavily moduled machine. This is the core trade-off of beaconed builds: the beacon power is a fixed cost regardless of what the machine is crafting, while the machine's power scales with its consumption multiplier. At 7.49 MW total, the setup produces 9.05 items per second for a 1-second recipe, or about 827.6 MW per item per second. An unmoduled AM3 array producing the same throughput would need 8 machines at 3.00 MW total, with no beacon overhead but a much larger footprint.
Diminishing returns in practice
The profile array's sqrt scaling means there is a sweet spot for beacon count. The table below shows how the total speed bonus from beacons grows, assuming each beacon holds two speed module 3s at normal quality.
| Beacons | Profile factor | Total speed bonus | Speed multiplier (beacons only) | Beacon power |
|---|---|---|---|---|
| 1 | 1.0000 | +150% | x 2.50 | 480.0 kW |
| 2 | 0.7071 | +212.1% | x 3.12 | 960.0 kW |
| 4 | 0.5000 | +300% | x 4.00 | 1.92 MW |
| 8 | 0.3535 | +424.2% | x 5.24 | 3.84 MW |
| 12 | 0.2886 | +519.5% | x 6.19 | 5.76 MW |
| 16 | 0.2500 | +600% | x 7.00 | 7.68 MW |
Going from 4 to 8 beacons adds +124.2% more speed bonus but doubles beacon power from 1.92 MW to 3.84 MW. Going from 8 to 12 adds +95.3% for another 1.92 MW. The marginal benefit shrinks while the marginal cost stays constant. In practice, 8 beacons is the standard for assembling machines (it fits around the 3x3 footprint with room for belt and inserter access), and 12 is the practical maximum for larger entities such as oil refineries.
Choosing modules for a beaconed build
Speed modules in beacons are the default choice for throughput-focused builds. They are the only module category that both fits in a beacon and directly increases output. Efficiency modules can go in beacons to reduce the machine's power draw, but the beacon's own 480.0 kW is unaffected, so the net power savings are smaller than they appear.
Productivity and quality modules cannot be placed in beacons at all. They go in the machine's own slots, where they apply at full strength without the profile penalty. The standard high-throughput configuration is productivity modules in the machine and speed modules in the beacons: the productivity gives free extra outputs, and the beacon speed compensates for the productivity speed penalty. This combination is why beaconed smelting and circuit production typically uses prod modules in the furnaces or assemblers and speed modules in the surrounding beacons.
For a machine with four own slots and eight surrounding beacons, the choice between four speed modules and four productivity modules in the machine depends on the goal. Four speed modules add +200% speed and +280% power. Four productivity module 3s add +40% productivity (free outputs) but -60% speed and +320% power. The beacon speed bonus of +424.2% more than overcomes the -60% speed penalty, making the prod-plus-speed-beacon configuration strictly better for raw item output on productivity-allowed recipes.
Supply area and layout
The beacon's supply area distance is 3 tiles, meaning it affects machines whose collision box is within 3 tiles. For a 3x3 assembling machine, beacons can be placed in the ring of tiles immediately surrounding the machine and one tile further out. The maximum number of beacons that can cover a single assembling machine depends on the orientation of belts, inserters, and underground belts, but 8 is achievable in a compact layout and 12 is possible with careful routing.
Beacons do not need power poles directly adjacent; they are powered through the same electric network as the machines they affect. A substation's large supply area can power a row of beaconed machines without individual poles. The beacon's own power draw of 480.0 kW is on the "secondary-input" priority, meaning it draws power after machines on the primary priority but before lights and turrets.
Beaconing different machine types
The worked example uses an assembling machine 3, but beacons affect any machine with module slots, and the arithmetic is the same regardless of what the machine does. The differences are in how many beacons fit around each footprint and how much the machine's base power draw contributes to the total.
Electric furnaces have a 2x2 footprint and two module slots. Around a single furnace, up to eight beacons can fit in a compact row layout, but furnaces are usually built in long columns where beacons are shared between adjacent furnaces. A beacon placed between two furnace columns covers machines on both sides, which halves the beacon-per-furnace cost. This shared-beacon pattern is why beaconed smelting arrays are the most power-efficient use of beacons: each beacon's 480.0 kW draw is amortised across multiple machines.
Oil refineries have a 5x5 footprint with three module slots. Their larger size allows more beacons around the perimeter, up to twelve in a well-routed layout. The refinery draws 420.0 kW at base, which is high enough that the consumption penalty from speed modules matters. Refineries also accept productivity modules in their own three slots, and the standard configuration uses prod modules in the refinery with speed beacons around it. Chemical plants follow the same pattern with three module slots and a 3x3 footprint.
Mining drills accept beacons but are rarely beaconed in early bases. The electric mining drill has three module slots and draws 90.0 kW, and the beacon supply area of 3 tiles covers multiple drills when placed over an ore patch. Productivity modules in the drills with speed beacons between them is the late-game mining configuration, but the beacon power overhead is difficult to justify until the ore patch is far from the main base and belt throughput becomes the bottleneck.
Pollution and quality interactions
Speed modules increase pollution by a percentage that scales with the machine's base pollution, and that increase is transmitted through beacons. A beacon carrying two speed module 3s transmits a pollution bonus of +140% (the consumption field drives the pollution multiplier in the game's effect system) at full effectivity. For machines that already produce significant pollution, such as furnaces and miners, beaconed speed can substantially increase the biter attack rate. Efficiency modules in the machine's own slots offset both power and pollution but do not transmit through beacons.
The quality penalty on speed modules is small per module but compounds across many beacons. Each speed module 3 carries a -2.5% quality effect, meaning it reduces the probability of higher-quality output. When a machine is covered by eight beacons each carrying two speed module 3s, the transmitted quality penalty is significant, which makes speed-beacon builds poor choices when quality output is the goal. For pure throughput builds where output quality does not matter, the penalty is irrelevant.
Quality modules themselves cannot be placed in beacons. They go directly in the machine's own slots, where they apply at full strength without the profile sharing factor. A quality-focused build therefore uses quality modules in the machine and speed modules in the beacons to compensate for the quality module's 5% speed penalty. The beacon speed bonus more than overcomes that penalty in an 8-beacon layout.
Common beacon mistakes
The most common mistake is placing beacons without checking that the machine is actually in the supply area. The beacon affects machines whose collision box is within 3 tiles, which is a square region, not a circle. A beacon placed diagonally adjacent to a machine covers it, but a beacon placed four tiles away does not, even though the visual supply area may appear to touch. The supply area distance is measured in tiles from the beacon's center to the machine's collision box, and underground belts or pipes can block placement in the tiles a beacon would need.
The second common mistake is ignoring the profile array. Players sometimes assume that eight beacons deliver eight times the module effect of one, when in fact they deliver 2.83 times due to the sqrt scaling. This leads to overestimating throughput and underbuilding the machine count. The coverage table above makes the actual multiplier explicit: eight beacons with two speed module 3s each deliver +424.2% speed bonus, not +1200%.
The third mistake is mixing productivity modules into beacons. The
beacon prototype explicitly lists only consumption, speed, and
pollution in its allowed_effects field. Productivity and
quality modules placed in a beacon have no effect; they occupy a slot
and transmit nothing. Wasting a beacon slot on a module it cannot
transmit is a silent error because the beacon appears to be working
(it still draws power) but the expected bonus never arrives.
Finally, players sometimes underestimate beacon power. The 480.0 kW per beacon is constant regardless of whether the beacon is transmitting to one machine or several. A row of eight beacons draws 3.84 MW on its own, which is comparable to the machine they support. Before building a large beaconed array, check that the power grid has enough headroom for the beacons plus the moduled machines, or brownouts will reduce crafting speed and defeat the purpose of the beacon investment.
Applies when…
These calculations apply when:
-
You are playing Factorio 2.1.12. Beacon prototype fields
(distribution effectivity, profile array, supply area, power draw)
and all module effects are read from
data/2.1/machines.jsonanddata/2.1/items.json. A future version that changes these values will change every figure on this page. - The profile factor is applied per beacon at the count covering the machine. If beacons are added or removed, the profile index changes and every beacon's contribution recalculates.
- The worked example uses normal-quality beacons. Higher quality beacons have higher distribution effectivity as shown in the quality table, which changes the transmitted effects proportionally.
-
Productivity modules cannot be placed in beacons. This is a game
restriction, not a data limitation. The beacon's
allowed_effectsfield lists only consumption, speed, and pollution. - Power figures are steady-state draw. Beacon power is constant; machine power varies with the consumption multiplier. No startup surge or fuel bonus is included.
Spot an error or an out-of-date figure? Contact us at [email protected].
Related
- Smelting ratios — beaconed furnace arrays and prod-module configurations
- Science pack ratios — throughput targets for beaconed science production
- How production ratios actually work — how crafting speed and productivity combine
- Main bus design — feeding beaconed production blocks