Calculators that turn the research behind our articles into something you can act on. Everything runs in your browser, nothing is sent anywhere, and there is no sign-up.
Why these give you ranges instead of a number
Most calculators in this space are published by companies that sell the thing being measured, and they hand you one confident figure. The evidence underneath rarely supports that. OSHA gives postural ranges rather than a correct desk height, and the caffeine timing figures come from a statistical model fitted across studies, not from a trial that tested a cutoff.
So these tools give ranges, they name the source for every figure, and where the arithmetic is ours rather than a published result they say so on the result itself. Where a source stops, the tool stops: the caffeine calculator refuses to answer for a drink below the smallest dose its model covers, and the interruption tool exists mainly to show why the number people quote is one no study actually supports.
Common questions
Do you sell any of the equipment these recommend?
No. We sell nothing, and none of the tools recommend a product or a brand. The desk tool tells you what fits the body you measured; the rest give you a figure and the caveats that come with it. What you buy, if anything, is your call.
Is anything I type stored or sent to you?
No. All the arithmetic happens in your browser. Your last entries are kept in your own browser’s local storage so the tool remembers them next visit, and that never leaves your device. Nothing reaches us or anyone else.
Are these medical advice?
No. They are general educational tools built from occupational health guidance and published research. If you have pain, a health condition, or you are pregnant or taking medication, that is a conversation with a clinician rather than a calculator. See the medical disclaimer.