How it works
TDEE calculator — the short version
Every TDEE Calculator on this page runs the same TDEE calculator logic a chartered accountant or coursework tutor would scribble on the back of an envelope — just faster, and reproducible.
For a TDEE calculator you can defend in a meeting, TDEE Calculator shows the figure AND the working. Copy the working, not just the number — that's where the conversation moves forward.
These numbers are guidance, not a prescription — your plate still matters more than the tracker. Think of an average week rather than today — then work out the numbers and the rest of this page explains what the answer means.
Use 1.2 for sedentary, 1.375 for light exercise 1–3×/week, 1.55 for moderate 3–5×/week, 1.725 for hard 6–7×/week, 1.9 for very hard + physical job.
On this page you will see Nutrition & Fitness, NHS and British Nutrition Foundation treated as first-class terms — each one is linked to the calculators and references that use it, so you can follow the thread without retyping queries into a search bar.
The formula we run is TDEE = BMR × activity factor. You'll see each term laid out in the worked example below.
If it helps, jump straight to the Nutrition hub or compare with the BMR Calculator and the BMI Calculator — those two calcs are the ones readers usually open right after this page.
From inputs to answer, in full
Consider a realistic scenario and follow it through:
Use 1.2 for sedentary, 1.375 for light exercise 1–3×/week, 1.55 for moderate 3–5×/week, 1.725 for hard 6–7×/week, 1.9 for very hard + physical job.
Every run comes back to TDEE = BMR × activity factor — change the inputs, the structure of the answer stays.
Moments this tool earns its keep
TDEE Calculator is aimed at people arriving with questions like these:
- "What is TDEE"
- "Activity multiplier TDEE"
- "How many calories should I eat"
- "What is tdee calculator"
- "How to calculate tdee calculator"
- "Tdee calculator formula"
Where the number stops being useful
Every tool has an edge where it stops being the right answer. TDEE Calculator is no exception:
- For legally binding tax or medical decisions — cross-check with HMRC, NHS or a qualified professional.
- For very large or very small extremes the rounding error outgrows the useful precision.
- When the underlying rate or threshold has changed since the page was last reviewed — always verify with the primary source.
- When the input you have is already a derived figure (net of something) — feeding it in as "gross" will double-subtract.
Watch-outs before you trust the number
Every time you work out the numbers for a new scenario, one of these creeps in — it's worth knowing them ahead of time.
- Misreading the unit in the label — 'per year', 'per month' and 'per day' versions of the same figure differ by 12× or 365×.
- Taking a ratio and multiplying it by the wrong side of the inputs — always write the ratio as A/B with labels before running.
- Trusting a screenshot of someone else’s calculation — rerun it yourself with the same inputs, numbers drift.
- Assuming percentages add up. 10% off then 10% more is not the original price — it is 99% of it.
- Not refreshing the page when thresholds are date-sensitive. If the page was cached yesterday, bank rates may already be yesterday’s.
The sources behind the numbers
Where the maths needs an external authority, we cross-check against:
- NHS
- British Nutrition Foundation
Works well alongside
If this question keeps coming up for you, the same cluster of tools usually comes next:
- BMR Calculator — Estimate your Basal Metabolic Rate — the calories your body burns at rest — with the Mifflin-St Jeor equation.
- BMI Calculator — Check your Body Mass Index in metric or imperial, with NHS weight categories explained.
- Macronutrient Calculator — Split your daily calories into protein, carbs and fat in grams, based on your body weight and training goal.
How we keep this accurate
Our calculadoras run on pure, unit-tested functions — the same logic lives in the browser and in the CI test suite. When tax rates, thresholds or official figures move, the update lands within 24 hours of the announcement. You can read the editorial policy and corrections policy.
Found an out-of-date number on TDEE Calculator or anywhere else in the Nutrition toolkit? Send it to the editorial desk and we'll patch it. Or browse the full calculadora directory for the next tool you need.