Ideal weight calculator

What the Ideal Weight Calculator Does

Need a reliable Ideal Weight figure in under a minute? You are in the right place. The Ideal Weight calculator below applies the standard formula instantly — and this page is its complete owner’s manual: what Ideal Weight means, how to enter your numbers, the maths under the hood, and a worked example. Charts promise one ‘ideal’ number, but bodies vary — an ideal weight calculator gives you a healthy range from the classic medical formulas.

You may also need our Waist-to-Hip Ratio calculator, Ovulation calculator, Pregnancy Weight Gain calculator — they cover the neighbouring calculations people usually run alongside Ideal Weight.

Quick note: this guide is for general information only and is not medical advice. If you have a health condition or a result worries you, talk to a qualified clinician.

How to Use This Calculator

Enter your figures into the fields below. Ideal body weight formulas were developed for drug dosing and clinical screening, not vanity.

• Height: The sole input the classic formulas need.
• Sex: Formulas differ for men and women.
• Frame size (optional): Small, medium or large adjusts the range.

The result appears instantly, with a breakdown of each step. If a figure looks unexpected, double-check your units first — metric versus imperial mix-ups are the most common cause of surprising results.

The Ideal Weight Formula

The calculator applies this standard formula:

Devine — Men: 50 + 2.3 × (inches − 60); Women: 45.5 + 2.3 × (inches − 60)
Robinson — Men: 52 + 1.9 × (inches − 60); Women: 49 + 1.7 × (inches − 60)
BMI range: 18.5 × h² to 24.9 × h²

• Height: In inches over 5 feet (60 inches).
• Formula choice: Devine is most used clinically.
• Healthy range: ±10% around the formula result, or the BMI band.

All three formulas agree within a few kilos for average heights; they diverge at extremes.

Worked Example

Here is the method applied to realistic figures:

1. Man, 5’10” (70 inches) → 10 inches over 5 feet.
2. Devine: 50 + 2.3 × 10 = 73 kg.
3. Robinson: 52 + 1.9 × 10 = 71 kg.
4. Healthy range ≈ 66–80 kg; BMI band for 1.78 m: 58.6–78.9 kg.

Frequently Asked Questions

What is my ideal weight?

It depends on height, sex and build — the classic formulas give a centre point, and ±10% around it (or the BMI 18.5–24.9 band) is the sensible range. The calculator shows all of them.

Which ideal weight formula is most accurate?

Devine is the clinical standard (drug dosing); Robinson and Miller are close variants. None accounts for muscle or frame — treat them as estimates.

Is BMI better than ideal weight formulas?

They answer slightly different questions, but the BMI healthy range is the more modern screening tool. Using both together — formula centre plus BMI band — is best.

Does ideal weight change with age?

Formulas do not adjust for age, but healthy body composition shifts: older adults benefit from slightly higher weight to protect against frailty and bone loss.

Why do the formulas give different answers?

They were derived from different datasets (Devine from drug-dosing data in the 1970s). Differences of 2–4 kg are normal — that is why a range beats a point.

Units deserve a final word of caution, because they cause more Ideal Weight errors than any other single factor. Metric versus imperial, monthly versus annual, percentages versus decimals — pick one system and convert everything before you start. The calculator is literal: it will compute a flawless answer to whatever you typed, right or wrong.

Rounding is another quiet trap. Round only the final result, never the intermediate steps — early rounding compounds through multi-step calculations and can shift the answer by more than you would expect. Let the calculator keep full precision internally and present the tidy number at the end.

Share the method, not just the answer. When Ideal Weight comes up in discussion — with a partner, an adviser, a colleague — walking through the inputs and the worked example builds agreement far faster than quoting a bare figure. People trust numbers they have seen derived; the example section above is your ready-made walkthrough.

Finally, remember that Ideal Weight is one instrument on the dashboard, not the whole dashboard. The related guides below connect it to the neighbouring calculations that complete the picture. Readers who follow those links consistently report the same thing: each individual figure makes more sense once you see how they fit together.

It is also worth stressing what Ideal Weight cannot do. No calculator captures every nuance of a real situation — unusual circumstances, edge cases and judgement calls still need a human. Use the figure as a strong, evidence-based starting point, and apply common sense (or professional advice) for the last mile. That balance is the mark of someone who uses tools well.

Bookmark this page alongside the calculator itself. Most readers return to Ideal Weight calculations at decision points — a change in income, a new goal, an annual review — and having both the tool and the explanation one click away turns each revisit into a thirty-second task instead of a research project.

A useful habit is re-running the Ideal Weight calculation whenever your circumstances change — new figures in, fresh answer out. Stale numbers are one of the quietest sources of bad decisions: the maths was right once, but the world moved on. A quick recalculation takes seconds and keeps every downstream decision honest.

If your result surprised you, treat the surprise as information rather than error. Unexpected Ideal Weight figures usually point at an input you have been estimating optimistically, a rule you did not know applied, or a genuine change worth investigating. Dig into the breakdown the calculator provides — the ‘why’ is almost always sitting in one specific line.

Consistency beats precision in tracking. Measuring Ideal Weight the same way, under the same conditions, on a regular schedule produces trends you can trust — even if any single reading carries a little noise. Pick a routine (monthly, quarterly, whatever fits) and stick to it; the pattern that emerges over time is the real insight.