Ideal Body Weight Calculator
See a classic ideal weight and a realistic range
Ideal body weight formulas, ranges and limits FAQ
What does this ideal body weight calculator do?
It takes your adult height and sex and shows a classic ideal body weight from several formulas plus a healthy weight range based on BMI 18.5–24.9. That way you see a band of reasonable numbers, not just one rigid “perfect” weight.
Which ideal body weight formulas does it use?
The tool combines the widely cited Devine, Robinson and Miller equations for adults, which all estimate weight in kilograms from height in inches over 5 feet. It averages their results into one simple “classic IBW” number for male and female entries.
What is the “healthy range” based on?
The range uses your height with a BMI band of 18.5–24.9, which many organisations treat as a typical adult healthy weight range. The calculator turns that BMI band into minimum and maximum weights in your chosen units.
Why can athletes or very muscular people fall outside this band?
BMI and classic IBW formulas do not account for high muscle mass or bone density. A strength athlete or sprinter might have a BMI above 25 but a very low body fat percentage. In those cases, body composition, performance and medical advice matter more than a generic range.
Can I use this for children or teenagers?
No. These formulas and BMI bands are designed for adults. Children and adolescents use age- and sex-specific growth charts and percentiles. Ask a paediatric team which tools make sense for a younger person.
Should I aim for the exact ideal body weight number?
Not usually. In practice clinicians care more about a range that fits your health, history and goals than one exact number. For many people, feeling well, keeping key health markers in range and maintaining a weight they can live with matters more than chasing a precise “ideal”.
When should I talk to a professional instead of just using this?
If you have long-term conditions, major weight changes, eating disorder history, pregnancy, or big concerns about weight, treat this as background education only and work with your healthcare team on targets and next steps.
How to use this ideal body weight calculator
This page turns adult height into a classic ideal weight plus a realistic range. Instead of one strict target, you see a band that links height-based formulas with typical BMI guidance.
1. Choose units and enter adult height
Start with the units box. By default it uses US feet and inches. Enter feet in the top box, inches below it. If you prefer metric, switch to centimetres and add your height rounded to the nearest cm. The calculator works for most adult heights between roughly 140–210 cm.
2. Pick the sex entry that fits your medical records
Classic IBW equations are written for male and female categories. If your medical records use one of these, choose it so the tool can show a combined classic IBW number. If you prefer not to map to those formulas, select “Other” and the tool will still show the BMI-based range without a sex-specific ideal.
3. Hit “Calculate ideal weight” to see results
The summary shows:
- A classic ideal body weight (or “—” if you chose the range-only option).
- A healthy weight range based on BMI 18.5–24.9 for your height.
- The height used and units you selected.
All values appear in pounds when US units are selected, or kilograms when metric is selected, so you can read them alongside labels or clinic notes.
4. Copy the summary into notes or check-ins
Use Copy summary to paste the numbers into a notes app, a progress sheet or a coaching or clinic message. That way everyone sees the same ideal and range without re-calculating.
5. Treat the numbers as a conversation starting point
Ideal body weight and BMI bands are starting points for discussion, not final verdicts. If the suggested range feels unrealistic, clashes with medical advice, or causes stress around food or body image, bring that up with your care team. The “right” weight for you can sit outside generic tables when other health factors are considered.
If you notice big changes in weight, energy or health markers over time, it is better to get personalised support than to chase a number from any calculator on your own.
How the ideal body weight and range math works
The calculator combines classic IBW formulas and a BMI-based healthy range so you can see how different methods line up for the same height.
1. Converting your height into inches and metres
Internally the tool turns your height into both:
- Height in inches (for classic IBW formulas that use “inches over 5 feet”).
- Height in metres (for BMI calculations).
For US entries, feet and inches are combined into total inches. For metric entries, height in centimetres is converted automatically.
2. Classic Devine, Robinson and Miller formulas
For male and female entries, the calculator uses three well-known adult IBW equations, all based on height in inches above 5 feet:
- Devine (1974): 50.0 kg + 2.3 kg × (height in inches − 60) for men; 45.5 kg + 2.3 kg × (inches − 60) for women.
- Robinson (1983): 52 kg + 1.9 kg × (inches − 60) for men; 49 kg + 1.7 kg × (inches − 60) for women.
- Miller (1983): 56.2 kg + 1.41 kg × (inches − 60) for men; 53.1 kg + 1.36 kg × (inches − 60) for women.
The tool averages these three values into a single classic IBW number in kilograms, then converts it into pounds when you use US units.
3. BMI-based healthy weight range
The range uses the standard adult BMI formula:
BMI = weight (kg) ÷ height (m)²
The tool inverts this to find weights at BMI 18.5 and BMI 24.9 for your height:
Weight (kg) = BMI × height (m)²
Those two weights become the low and high ends of the healthy band that is shown in kilograms or pounds.
4. Rounding and why results are approximate
All values are rounded to keep them easy to read and remember. Because different organisations sometimes use slightly different BMI cut-offs, and because individual health varies, you should treat these results as approximate guide rails rather than strict limits.
If the numbers you see here differ from targets set by your clinician, follow the medical plan you have agreed together and use this tool only for context and education.
References and further reading on ideal body weight
These resources describe classic ideal body weight equations and adult BMI-based healthy weight ranges:
- Family Practice Notebook — Ideal Weight in Adults — lists equations for adult ideal weight, including Devine, Robinson and Miller.
- CDC — Adult BMI Categories — shows BMI 18.5–24.9 as a typical adult healthy weight range and outlines other categories.
Use these for background reading, then work with your own healthcare team on the targets and ranges that best fit your health, history and goals.