factorio ratio calculator

What this Factorio ratio calculator does

This tool is built for one job: turning a target output rate into practical factory numbers. Give it a recipe, machine speed, and production goal, and it tells you how many assemblers (or furnaces/chemical plants) you need. If you add ingredient quantities, it also computes the input draw in items per second and per minute.

In short, it helps you answer the classic mid-game and mega-base questions: “How many machines do I need?” and “Can my input lines keep up?”

How the math works

Core formulas

• Effective output per craft = output per craft × (1 + productivity bonus)
• Crafts needed per second = desired output per second ÷ effective output per craft
• Crafts a machine can do per second = crafting speed ÷ recipe craft time
• Machines required = crafts needed per second ÷ crafts a machine can do per second

For ingredients, each craft consumes its listed inputs. So once we know crafts per second, ingredient demand is straightforward:

• Ingredient per second = ingredient quantity per craft × crafts needed per second

Example: green circuits at 60 per minute

Choose Electronic circuit, set output to 60 items/min, and use an Assembling machine 2 (speed 0.75). The calculator gives:

• Exact machine count: 0.67
• Build count: 1 assembler
• Input draw: 60 iron plates/min and 180 copper cable/min

That quickly informs the next design step: one cable assembler can feed one green circuit assembler at this rate, which is a classic early-game ratio pattern.

When to use productivity bonus

Productivity modules increase output per craft without increasing ingredient cost per craft. That effectively lowers input required per final item and lowers machine count for a fixed target. Enter your total productivity percentage directly (for example, 24 for +24%).

Useful planning tips

1) Design around stable rates

Pick a target throughput first (such as 30, 60, 120, or 300 items/min), then back-calculate each upstream ingredient. Consistent rates make scaling much easier.

2) Always round machine counts up

Fractional machines are useful for planning, but your actual build needs whole entities. If the calculator says 7.2 assemblers, place 8.

3) Check bottlenecks at interfaces

Even perfect machine ratios can fail if inserters, belts, or trains cannot keep up. Use this tool to identify expected flow, then verify your logistics layer can sustain it.

Common uses

• Balancing intermediate products like gears, cable, and circuits
• Sizing smelting blocks from science pack demand
• Planning module-heavy late-game production with productivity bonuses
• Building train outposts with clear per-minute load targets

Final thought

Factorio rewards clear systems thinking. A fast ratio calculator turns guesswork into repeatable design. Use it iteratively: pick a target output, calculate required machines, add ingredient rates, then move one level upstream until your whole production chain is balanced.