About FitMetricLab

FitMetricLab is a free, open-access fitness calculator platform operated by Brightscale Labs Limited, a company registered in England and Wales (Company No. 16990009). Every tool here is a pure math function: you enter a number, you get a number. There is no store, no training plans, no diet programs, and no personalised recommendations — deliberately.

What we do

We offer 100+ free fitness calculators spanning body composition, heart-rate zones, BMR and macros, strength standards, running performance, cycling power, and nutrition intake. Each tool is designed to provide instant, accurate mathematical results while clearly explaining the formula and assumptions behind every calculation.

Our platform is built for education and illustration — we do not provide medical, nutritional, or training advice, and we do not generate personalised plans of any kind.

Why we built this

Most fitness calculators on the web are buried inside supplement stores and training sites. The result is slow pages packed with product links, and calculators that work as lead magnets rather than tools. FitMetricLab is the opposite: every page is a calculator first, loads fast, works on mobile, and never pushes a product in the calculator flow.

How formulas are sourced

Every calculator uses a public, published formula. Each tool page shows the formula in full and links to the original source where one exists. Where a formula was derived against a specific population sample (for example Jackson-Pollock, Daniels VDOT, Mifflin-St Jeor, Coggan FTP zones, IPF DOTS), we cite the original paper and note the validation context.

We do not invent formulas or tune them to match a marketing outcome. If a formula has known limitations (age range, sex bias, accuracy ± a stated margin), the tool page says so.

How we keep FitMetricLab free

FitMetricLab is free to use. The site currently runs without any advertising or affiliate links. In future, to cover hosting and development costs, we may introduce Google AdSense advertising and clearly-marked affiliate links to fitness products. If we do, you will be shown a consent banner on your first visit and advertising will only load after you accept.

Calculator outputs and methodology notes are independent of any commercial relationships, present or future. We will not let advertisers or affiliates affect the accuracy or objectivity of any tool.

Our principles

• Free forever. Every calculator is free. No sign-ups, no paywalls, no hidden fees.
• Educational only. We provide mathematical illustrations, not medical, nutritional, or training advice. All results are estimates for educational purposes.
• Privacy first. Your calculations run entirely in your browser. We never store, transmit, or sell your inputs or results.
• Transparent formulas. Every tool shows the exact formula used and links to its primary source. No black boxes — you can verify every calculation independently.
• Accuracy commitment. Tool logic is unit-tested. Expected outputs are tracked per tool. When we find an error, we fix it and document it.
• Built for everyone. From beginners learning what BMR means to coaches checking a Wilks score — our tools serve all experience levels.

Accuracy and review process

Every tool ships with a test value and an expected output. Our build pipeline runs the math engine against those inputs on every change — if the result drifts from the expected output, the change is blocked. Calculator content (formula notes, FAQs, methodology) is reviewed by a human editor before release. Where AI assistance is used in drafting structural content, the output is verified against the named primary source before publishing. See our Editorial Policy for the full review cycle.

What this site is not

• Not a medical site. We do not diagnose, screen for conditions, or provide treatment.
• Not a dietitian. We do not tell you how many calories to eat.
• Not a coach. We do not generate training programs or prescriptions.
• Not a health record. Inputs you type never leave your device.

Team

FitMetricLab is built by a small team at Brightscale Labs Limited, focused on calculator-first web properties. Every tool runs entirely in your browser, shows the formula behind its result, and is built to stay accurate without tracking you or storing your inputs.

Regulatory information

Brightscale Labs Limited is registered in England and Wales. Registered office: 8 Flay Field, Tithebarn, Exeter, England, EX1 3YA. Company Registration Number: 16990009.

This website is an educational fitness reference platform. It is not a regulated healthcare, nutrition, or coaching provider. All tools are provided for illustrative purposes and do not constitute medical advice or a substitute for qualified professional care.

Contact

Questions, formula corrections, or accessibility feedback? Email contact@brightscalelabs.com or use our contact page.