BMR Calculator UK
Our free BMR calculator calculates your Basal Metabolic Rate — the number of calories your body burns at complete rest — using the Mifflin-St Jeor formula. This figure forms the foundation of any accurate UK diet or fitness plan.
Basal Metabolic Rate
This is the number of calories your body burns at rest to maintain basic life functions like breathing and heart rate.
Activity Multipliers
How the Mifflin-St Jeor BMR Formula Works
This calculator computes your Basal Metabolic Rate using the Mifflin-St Jeor formula — the most clinically validated BMR equation. For men: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5. For women: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161. Inputs required: sex, age, weight (kg or lbs), height (cm or inches). Outputs: BMR in kcal/day and suggested calorie intakes at each activity level.
Frequently Asked Questions
Is the UK BMR Calculator based on NHS guidelines?
Yes. Where applicable, our bmr calculator uses the standard clinical formulas and reference ranges recommended by the NHS and recognised UK medical bodies. Results are for informational purposes and are not a substitute for medical advice.
How accurate is the BMR Calculator for UK adults?
Our bmr calculator uses validated clinical formulas applied to healthy adults. Accuracy depends on the quality of the inputs provided. For medical diagnoses, treatment plans, or clinical decisions, always consult a qualified UK GP or healthcare professional.
Can I use this BMR Calculator on my mobile in the UK?
Yes. Our bmr calculator is fully optimised for mobile use on any UK smartphone or tablet, including iPhone, Android, and iPad. No app download is required — simply visit CalcMax in your browser.
Does this BMR Calculator apply to children as well as adults?
Standard formulas used in this calculator are calibrated for adults. Children have different healthy ranges and reference values. For children's health metrics, please consult a UK paediatrician or your child's GP rather than using adult-only calculators.
Is this BMR Calculator free to use without a sign-up?
Yes. Our bmr calculator is completely free to use. No account, registration, or personal details are required. Simply open the tool in your browser and begin calculating immediately on any device.