Weight Analysis Tool — Free BMI, Healthy Weight & Calorie Check

Your weight analysis

Use your real measurements for an accurate result. If you don't know your waist size, leave it blank — everything else still works.

Sex

Age (years, 10–100)

Height

Weight

Waist (optional — measured at the navel)

Daily activity

Your goal

Your numbers are calculated in your browser and never leave this page.

Your results will appear here

Your BMI, healthy range, calorie target and personal plan — calculated the moment you press Analyse my weight.

Your BMI—

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Healthy range for you

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for your height

To reach healthy range

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Est. body fat

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estimate from BMI & age

Calories to maintain

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BMR —

Your daily target

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Protein & water

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Your personal plan

Change any number on the left and your results — and your card — update automatically.

How to read your BMI

BMI (Body Mass Index) compares your weight to your height. It's a useful first check for most adults — it doesn't measure muscle or where fat is stored, which is why this tool also estimates body fat and waist ratio.

Underweight

Below 18.5

May mean you're not getting enough energy or nutrients. Gaining gradually with strength training is usually the goal.

Healthy weight

18.5 – 24.9

Associated with the lowest health risk for most adults. The aim here is staying active and keeping the habits that got you here.

Overweight

25 – 29.9

A modest, steady loss — even 5% of body weight — measurably improves blood pressure, blood sugar and joint strain.

Obese

30 and above

Raises the risk of type 2 diabetes, heart disease and sleep apnoea. Small sustainable steps work — and a clinician can add real support.

How this tool works

Your measurements

Height, weight, age and sex feed standard formulas used by clinicians worldwide — the same ones behind BMI charts.

Your energy needs

The Mifflin–St Jeor equation estimates your resting burn (BMR), scaled by your activity to get the calories that maintain your weight.

Your plan

Your goal adjusts the calorie target, and your category shapes practical next steps you can actually keep doing.

Habits that move the number

No crash diets. These are the levers with the strongest evidence behind them, whichever direction your result points.

Eat

Build meals around protein and vegetables first — they keep you full on fewer calories.
Cut liquid calories first: soft drinks, juice and sweetened coffee add up fastest.
Eat slowly and stop at comfortably full, not stuffed. Your brain needs ~20 minutes to catch up.
A steady 0.5–1 kg per week is a safe, sustainable rate of loss for most adults.

Move

Walking is the most underrated tool: 7,000–9,000 steps a day changes the maths on its own.
Add resistance training 2–3 times a week to protect muscle while you lose fat.
Gaining? Progressive strength training plus a small calorie surplus builds muscle, not just weight.
Short and daily beats long and rare — consistency is the whole game.

Recover

Sleep under 7 hours raises hunger hormones and next-day snacking — protect your sleep.
Weigh yourself 2–3 times a week, same time of day, and follow the weekly trend — not daily swings.
Keep trigger foods out of easy reach at home; willpower is a weak strategy, environment is a strong one.
Stress drives emotional eating. A walk, a call, a pause — have a non-food reset ready.

Common questions

Is BMI accurate for everyone?

BMI is a screening tool, not a diagnosis. Very muscular people (athletes, bodybuilders) can score "overweight" with low body fat, and older adults can score "healthy" while carrying more fat than is ideal. That's why this tool also estimates body fat and, if you add it, your waist-to-height ratio — a waist under half your height is a good sign. For a full picture, a clinician can measure properly.

How fast should I lose weight?

For most adults, 0.5–1 kg (about 1–2 lb) per week is considered safe and sustainable. That usually means eating roughly 500 kcal a day below your maintenance level — which is exactly how the "lose" target in this tool is calculated. Faster loss is harder to keep off and can cost muscle.

Why does my calorie target change with activity?

The calories you burn at rest (your BMR) are only part of the story. Moving, working and exercising multiply that number — from about 1.2× for a desk-based day up to 1.9× for very physical work. Pick the activity level that matches your typical week, not your best week.

I'm underweight — how do I gain healthily?

Aim for a modest surplus (this tool adds about 300 kcal for the "gain" goal), prioritise protein, and pair it with resistance training so the weight you add is muscle. Nutrient-dense additions — nuts, dairy, olive oil, smoothies — help when your appetite is small. If you're underweight without knowing why, see a clinician first.

Does this tool store my information?

No. Every calculation runs in your browser on this page. Nothing you type is sent anywhere or saved.