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
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
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.
Thanks.