Health & Wellbeing2 min check

Ideal Weight Calculator

Estimate a healthy weight range for your height using the NHS BMI range and the classic Devine formula.

Short answer

The 'ideal' weight isn't a single number — it's a range. NHS healthy BMI 18.5–24.9 gives a sensible band; the Devine formula gives a single midpoint often used in medicine for drug dosing.

Step 1 of 10%

Calculation method, coverage and version

Inputs used: Height (cm), Sex assigned at birth.
Calculation approach: The calculator applies the rules and assumptions described in “How it works” to the values you enter. Rounding can cause small differences from an official or provider calculation.
Coverage: Health & Wellbeing. UK nations, tax treatment, local rules and provider criteria can differ; check the official sources shown below before acting.
Content version: No page-specific review date is currently published. Treat the result as indicative and verify current rules independently.

Not included unless explicitly requested: personal circumstances not entered, provider discretion, future rule changes, professional fees and case-specific exceptions. Read the full calculator methodology.

How it works

The healthy range comes from BMI 18.5 × height² to 24.9 × height². The Devine formula was originally designed for drug dosing and gives a single 'ideal' often used in medicine.

Worked example

Female, 165cm:

Healthy range: 50.4 – 67.8 kg
Devine ideal: 55.7 kg

Who should use this

•Anyone curious about a healthy target weight
•People starting a weight-management plan

Common mistakes

×Treating Devine as the only target — it's a single point
×Ignoring muscle mass — strong people can be heavier and very healthy
×Using on children — kids need percentile charts

Frequently asked questions

Should I aim for the Devine number?▾

Anywhere in the BMI 18.5-24.9 range is healthy. Devine is just one midpoint.

Why is muscle 'good' weight?▾

Muscle improves metabolic health, glucose handling, bone density and longevity — even when it pushes BMI higher.

Are these formulas accurate for older adults?▾

Older adults (70+) may benefit from a slightly higher BMI (23-27) — slightly higher reserves help recovery from illness.

Related calculators

BMI Calculator →Calorie Calculator →Weight Loss Calculator →