About BodyCalc

What this site is

BodyCalc publishes calculators for the numbers people check most often when they start a diet, a cut or a training block: daily calories, protein, body fat, hydration, heart rate zones and one-rep max. Every page works without an account, without an email address and without storing anything you type.

The site is deliberately narrow. We would rather answer eighteen questions properly than publish a hundred thin pages that repeat each other, which is why each calculator prints its formula, shows a worked example and links to the published source behind it.

Why the maths is public

Most calculator sites show a number and stop. You cannot tell whether the figure came from the Mifflin-St Jeor equation, Harris-Benedict or a guess. Every BodyCalc page prints the equation it uses, the units it expects and the activity multipliers behind the result, so you can check the arithmetic yourself or hand it to a clinician.

Where two formulas disagree - resting energy is the usual example - the page shows both rather than hiding the spread. Where a formula has a documented limit, such as the US Navy tape method for very lean or very muscular bodies, the page says so next to the result.

How we keep it correct

Each calculator is driven by a single test suite that compares the code against hand-computed values: one normal case, one boundary case and one bad-input case per formula. If a change to the maths breaks a known value, the build fails before anything is published.

Thresholds come from published sources such as the World Health Organization BMI cut-offs, the NICE waist-to-height guidance, the ACSM activity multipliers and the Compendium of Physical Activities for exercise energy cost. The exact list is on the methodology page.

Who pays for it

The site is free to use and is funded by the site owner. It carries no analytics scripts, no tracking pixels and no advertising code today. If that changes, the privacy policy and this page will say so plainly before anything is added.

Corrections

If a page is wrong, out of date or unclear, email hello@calc.idailycheck.xyz with the page address and what you expected to see. Fixes that change a published formula or threshold are dated on the page itself.

How the calculators are built

Every formula lives in one file. That file is tested against a fixed set of inputs and expected outputs before anything is published, so a change to one calculator cannot quietly alter another. The tests cover normal cases, boundary cases such as zero activity and one-rep inputs, and nonsense input that should be rejected rather than guessed at.

The pages themselves are static HTML generated ahead of time. The result you see on first load is already in the page, which means the numbers are readable by search engines and by anyone using a screen reader, and the page still works if a script fails. When you change an input, a small script recalculates in your browser and updates the URL so the calculation can be bookmarked.

There is no account, no database and no queue of jobs behind the calculator. Nothing you type is sent anywhere.

What BodyCalc is not

It is not a medical service. Nothing here diagnoses, treats or monitors a condition, and no page is written for someone managing diabetes, kidney disease, an eating disorder or a pregnancy. Those situations need a clinician who knows your history, and the general thresholds on this site can be actively misleading for them.

It is not a tracker. There is no diary, no weight log and no syncing, because storing body data creates obligations we would rather not have. Your browser history already records what you typed, and that is the only record that exists.

It is not a store. There are no accounts, no subscriptions, no advertising slots and no affiliate links, so no page here is written to sell you a powder, a device or a program.

Who the site is for

The calculators are built for healthy adults who want a defensible starting number and an honest statement of how far it can be trusted. That includes people setting up a first cut or bulk, people who have stalled and want to know which input to check, and coaches or students who need a quick reference for an equation.

They are not built for children or adolescents. Growing bodies need age-specific equations and clinical judgement, and the adult formulas on this site will give misleading numbers for them.

Accessibility and page weight

The pages are built to work without JavaScript, with the keyboard and with a screen reader. Headings follow a single order, the result table is a real table, form fields have visible labels rather than placeholder text, and colour is never the only cue for a status.

Each page loads one stylesheet and two small scripts, all served from this domain. There are no third-party fonts, trackers, tag managers or widget libraries, which keeps the pages fast and means no other company sees your visit through a script embedded here.

Dark mode follows your system setting, and a print stylesheet strips the navigation so a result prints as a clean one-page summary.

What happens when a formula changes

If a published equation is revised, or a guideline body changes a threshold, the affected calculator is updated and the page records the change. Pages carry a review date rather than a permanent publication date, so you can see how current the numbers are.

Old calculations are not kept. Because nothing is stored, there is no archive of results to migrate, and a permalink shared before a change will simply recalculate with the current formula when it is opened.

Where to start

If you are new to this, the fastest path is three pages: run the TDEE calculator, read the accuracy guide to see how wide the error bars are, then run the calorie deficit calculator to turn maintenance into a target. That takes about ten minutes and gives you a plan you can test for two weeks.

If a number looks wrong, the methodology page lists every formula and the guides explain the inputs most often entered incorrectly. Activity level is the usual culprit, followed by a stale body weight.

If you find a genuine mistake, the correction address above goes to a person. Reports that include the page, the inputs you used and the result you expected are the ones that get fixed fastest.

How to read a result table

Every result appears twice: once as a headline figure and once inside a table that shows the inputs it was built from. Read the table, not the headline. The headline answers the question you clicked for, while the table shows you the assumptions that produced it.

Figures are rounded for display and the calculation uses the unrounded values, so a number you reproduce by hand can differ in the last digit. That difference is rounding, not an error.