Jesse

I build and maintain FitCalcs. I am a software developer, and I read fitness and nutrition research as a personal interest rather than a profession. Every calculator, guide, and reference chart on this site is written and checked by me.

A note on the name: Jesse is the name I write under, not my full legal name. I keep my identity private because this is a personal side project, and I would rather say that plainly than imply something I am not. Everything else on this page is accurate, and the contact address below reaches me directly.

What I am not

This matters more than anything else on the page, so it comes first. I am not a doctor, a registered dietitian, a nutritionist, or a certified trainer. I hold no clinical qualification of any kind. Nothing on this site is medical advice, and no calculator here can diagnose anything or account for a condition, a medication, or a history of disordered eating. If any of those apply to you, a qualified professional who can actually examine you is the right person to ask, not a web page.

I mention this on every calculator as well, because a number rendered in a clean interface tends to look more authoritative than the estimate behind it deserves.

What I do bring to it

Two things, both modest. The first is that I have tracked my own weight, food intake, and training over time, and I have watched these formulas succeed and fail against my own data. That is experience, not expertise, but it is the reason this site is built the way it is: I know from my own numbers that a maintenance calorie estimate can be a few hundred calories off, so the site is designed to show you its working and its error bars rather than hand down a target.

The second is that being a developer makes a specific kind of accuracy cheap to enforce. The formulas live in code, in one place, with the published paper cited next to them — so I can guarantee that two pages quoting the same equation are running the same equation.

How every page here is built

These are the rules I hold the site to. They are checkable: pick any calculator and you should be able to confirm each one.

• Published equations only. Every result comes from a named, peer-reviewed or officially published formula — Mifflin-St Jeor for resting energy, the U.S. Navy circumference method for body fat, the WHO bands for body mass index, the 2011 Compendium of Physical Activities for the energy cost of exercise. I do not invent formulas or adjust published constants to taste.
• The source is on the page.Not a vague gesture at "studies show" — the actual paper, with authors, journal, and year, linked where a public link exists.
• Each formula is implemented once. The math lives in a shared library rather than being copied into each page, so a calculator and a chart that use the same equation cannot quietly disagree.
• The reference charts are generated, not typed. Every value in every table is computed when the site is built, by the same code that runs the calculators. Even the figures quoted in the surrounding text are computed rather than written by hand, so the prose cannot contradict the table beside it.
• Limitations are stated, not buried. Each page says where its method is weakest and by roughly how much — that the Navy body-fat method carries a standard error of several percentage points, that one-rep-max formulas fall apart above ten reps, that activity multipliers cannot see how much you actually move.
• Uncertainty is admitted. Where the evidence is genuinely unsettled, the page says so instead of picking the more confident-sounding answer.
• Every page carries a review date. If a page has not been checked recently, you can see that for yourself.

What I will not publish

No supplement or product recommendations. No before-and-after marketing. No claims that go further than the cited source actually supports. No invented statistics, and no citation dressed up to sound like it proves more than it does. No fear-based copy designed to keep you reading. If a question cannot be answered honestly with a calculator, the honest answer is that it cannot, and I would rather write that.

Corrections

I would genuinely rather be corrected than be wrong in public. If a formula looks misapplied, a result does not add up, a source is outdated, or a sentence overstates what the evidence shows, email hello@fitcalcs.app and tell me. I will check it against the source, fix what is wrong, and update the page's review date. Substantive corrections to a method get noted on the page rather than quietly edited away. The editorial policy sets out that process in full.

Errors already found this way are part of why the rules above exist. Building the reference charts surfaced a body-fat classification that put values sitting exactly on a category boundary into the wrong category, and it was fixed the same day.

What I have written

14 calculators, 7 guides explaining how to read the results, and 12 reference charts that publish the same calculations as lookup tables. The methodology page lists every formula the site uses along with its source and its known limitations, and about FitCalcs covers what the project is for.