Factorio Forums

Hi all,

I built a web-based production calculator for Factorio and I'd like to put it in front of this community before I push it any further, because you're the people who will find the bugs fastest.

The tool: smart-calculators.net — Factorio Production Calculator. Free, no account, runs in the browser, works on mobile.

What it does

Given a target item and a desired output rate (per second / per minute / per hour), it returns:

• The exact number of machines (assemblers, furnaces, chem plants, Foundry, EM Plant, Biochamber, Recycler)
• Crafting-machine utilization as a percent, so you can see whether to scale up or spread out
• Modules and beacons applied correctly, including the post-FFF #409 diminishing-returns formula (effective transmission = 1.5×√n)
• Belt count per tier (yellow / red / blue / turbo) for the output flow
• Total power draw in MW
• A full "show the math" panel for every number — recipe time, base speed, speed modifier, beacon contribution, productivity modifier, final division

Why another calculator

Kirk McDonald's calculator is the standard and FactorioLab is excellent. I'm not trying to replace them — I'm trying to fill a narrower gap: a calculator where every number shown comes with the formula that produced it, visible in the same view, without having to open a separate docs page. When Wube changes a multiplier (FFF #409 was the obvious case) the ratio calculators break silently; an audit panel catches that.

One specific correctness thing I care about: speed modules carry a -2.5% quality penalty each, applied once per module, not compounded. FactorioLab issue #1718 documented a result more than 10× off on a build using that combination; I wrote the calculator with that case as a regression test. If you feed it a bad recipe and it gives you an obviously wrong number, I want to know — that's the kind of feedback that matters most to me.

Space Age support

• Foundry (+50% built-in productivity, speed 4.0) — casting recipes
• Electromagnetic Plant (+50% productivity, 5 module slots)
• Biochamber on Gleba (nutrient-fuelled, spoilage not yet modelled)
• Recycler on Fulgora with the locked -75% productivity penalty
• Quality modules in the quality-output beta panel

Mining productivity is a research input; space-science loops are included. What it does not yet do: full planet-to-planet logistics, train scheduling, spoilage on Gleba chains, or blueprint import. Those are on the roadmap if the core ratio tool proves solid.

Asking for feedback

If you try it, please tell me:

• Any recipe where the number you get looks wrong — with the inputs you used, so I can reproduce
• Any Space Age mechanic that shipped after 2.0.x that the calc is missing
• UX friction — what you expected to see vs. what's there
• Anything else that would make you replace Kirk's or FactorioLab in your workflow. I don't expect to win that comparison right away, but I want to know the distance honestly.

Happy to answer questions in this thread, and if there's a formula you'd like the "show the math" panel to expose that I didn't think of, say so — that panel is the part I'm most flexible on.

Thanks.