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Every FitCalcs calculator in one place. Calorie and TDEE, BMI and waist-to-height, and a running race-time predictor, each showing the equation and UK data behind it.

Work out the calories you burn in any activity from your body weight and how long you did it, using MET values from the Compendium of Physical Activities.

Estimate your one-rep max from a weight and reps you can already lift, using the Epley and Brzycki formulas, with a percentage table to set your training loads.

Work out the UK units and calories in your drinks from volume and strength, and see how it compares to the NHS 14-unit weekly low-risk guideline.

Work out your basal metabolic rate, the calories you burn fully at rest, with the Mifflin-St Jeor equation, or the Cunningham equation if you know your body-fat percentage.

Estimate your body-fat percentage with the US Navy circumference method, using neck, waist and height (plus hip for women). Just a tape measure, no scales needed.

Work out your maintenance calories, a safe deficit and your BMI and waist-to-height ratio. The Mifflin-St Jeor equation and NHS categories, laid out in full.

Estimate how much water to drink a day from your body weight, exercise and the weather, with a baseline near the EFSA and NHS adequate-intake figures.

See your healthy weight range in kilograms for your height, from the NHS BMI band of 18.5 to 24.9, plus how far your current weight sits from it.

Turn your daily calories into a protein, carbohydrate and fat split for your goal. Protein is set per kilogram of body weight first, the way the research supports.

Work out your daily protein in grams, set per kilogram of body weight for your goal: general health, fat loss, muscle gain or endurance, using the ISSN ranges.

Estimate the date you reach your target weight from your current weight and a daily calorie deficit, using 7,700 kcal per kilogram, capped at a safe rate.

Score your 5K, 10K, half or marathon time as an age grade, your performance against the world best for your age and sex, using fitted WMA age factors.

See where you are in the nine-week Couch to 5K plan, the run and walk pattern for your week, and the pace you need for a goal 5K finish time.

Work out your five training heart-rate zones with the Karvonen method, which uses your resting pulse for a more personal result than a flat percentage of max.

Predict your 5K, 10K, half marathon and marathon times from one recent result, with per-kilometre pace, using the Riegel endurance formula.

Convert your step count into distance in kilometres and miles and the calories you burned, using a stride estimated from your height and the MET method for walking.

Estimate your VO2 max, the standard measure of aerobic fitness, from the Cooper 12-minute run or the Rockport 1-mile walk test, with a fitness rating.

BMI is a quick population screen but it cannot tell muscle from fat or say where you carry it. Waist-to-height ratio, the measure the NHS now prefers, captures the central fat that drives health risk. Here is when to use each.

Plain-English UK fitness guides that explain the numbers and link to the calculator behind each one: how many calories to lose weight, BMI vs waist-to-height, predicting your race time, and how much protein you really need.

Work out an honest calorie target to lose weight: estimate your TDEE, subtract a modest deficit of around 500 calories a day for about half a kilo a week, and adjust from there. With the Mifflin-St Jeor maths and UK guidance.

The UK reference intake is 0.75 g of protein per kilogram of body weight a day, enough to avoid deficiency. Active people, older adults and anyone in a calorie deficit usually do better nearer 1.2 to 2.0 g per kg. Here is how to set a sensible target.

Use one recent race result to estimate your 5K, 10K, half marathon and marathon times with the Riegel formula. How it works, why longer distances are best-case estimates, and how to use the prediction sensibly.

Headline UK statistics on physical activity, overweight and obesity, calorie intake and running, each cited to its primary source: the NHS Health Survey for England, Sport England Active Lives, the NDNS, parkrun and the London Marathon.

See how your activity, calorie intake and body stats compare to the UK population, using the NHS Health Survey for England, Sport England Active Lives and the National Diet and Nutrition Survey.

The real UK population figures for physical activity, overweight and obesity and diet, each with its sex or age breakdown, period, named primary source and access date. Drawn from the NHS Health Survey for England, Sport England Active Lives and the National Diet and Nutrition Survey.

is the editorial desk behind FitCalcs, the UK fitness, body and diet calculator site. Health tools cite their figures to named UK sources such as the NHS, Sport England and the NDNS, and are informational only, not medical advice.

FitCalcs is an independent UK fitness, body and diet calculator site, operated by Best Business Loans Ltd, where every tool shows its working and cites the official UK source behind the number.

The public registrations and identifiers for Best Business Loans Ltd, the company that operates FitCalcs, each linked to its primary register.

The named editorial desk behind FitCalcs. Every health figure is cited to a named UK source such as the NHS, Sport England or the NDNS, and tools are informational only, not medical advice.

Read-only public API and MCP server for FitCalcs fitness calculators. REST endpoints for TDEE, BMI and race-time prediction, an OpenAPI 3.1 spec, and three MCP tools. CC BY 4.0.

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Free UK calculators for calories and TDEE, BMI and waist-to-height, macros, running pace and more. Every tool shows the equation and the official UK data behind the number.