Ideal Weight Calculator

Formula	Ideal Weight ({{ weightUnit }})	Copy
{{ r.name }}	{{ formatWeight(r.value) }}

Ideal body weight is a height based estimate of a healthy mass that offers a simple reference for planning diet and training. Many people look for an ideal weight by height starting point to frame goals without complex measurements.

You provide your sex and height, then read four published estimates as individual results, an average, and a narrow range. Units can be shown in kilograms or pounds so numbers match everyday use.

As a quick example, enter 172 centimeters and select male. The four methods cluster in the high sixty kilogram band, and the average lands near the mid to high sixty range. That gives a practical first target for steady progress.

Treat the figures as a guide rather than a verdict. Consider present weight, activity, and body composition when deciding what to do next. If you are shorter than five feet, remember some methods only add weight above that threshold.

For clearer comparisons, keep units consistent across checks and use the frame adjustment if your build feels smaller or larger than average. Revisit the estimate over time to see how choices track with your plan.

This tool provides informational estimates and does not substitute professional advice.

Technical Details:

Ideal body weight (often abbreviated IBW) is estimated from stature using four classic height–based formula families that differ by sex. Each formula computes a baseline in kilograms and adds a per‑inch amount above 5 ft (152.4 cm), then applies an optional frame multiplier.

The calculation observes a single quantity directly—standing height—and transforms it into four weight estimates. Reporting the average alongside the minimum and maximum helps communicate central tendency and spread in familiar units.

Across formulas, results are broadly comparable for typical adult heights, though their slopes differ. These estimates are screening references, not measures of fat‑free mass, fat mass, or athletic performance.

\begin{array}{l} h_{ex} & = & \max (0, \frac{h_{cm} - 152.4}{2.54}) \\ W_{kg} & = & (b + s \cdot h_{ex}) \cdot f \\ W_{lb} & = & W_{kg} \cdot 2.20462 \end{array}

Symbols and units
Symbol	Meaning	Unit/Datatype	Source
hcm	Body height	cm or in	Input
hex	Inches above 5 ft	in	Derived
f	Frame multiplier	dimensionless (0.9, 1, 1.1)	Input
b	Formula base at 5 ft	kg	Constant
s	Per‑inch slope above 5 ft	kg / in	Constant
Wkg	Ideal weight (per formula)	kg	Derived
Wlb	Ideal weight (converted)	lb	Derived

Formula constants by sex
Formula	Sex	b (kg)	s (kg/in)
Devine	Male	50.0	2.3
Devine	Female	45.5	2.3
Hamwi	Male	48.0	2.7
Hamwi	Female	45.5	2.2
Robinson	Male	52.0	1.9
Robinson	Female	49.0	1.7
Miller	Male	56.2	1.41
Miller	Female	53.1	1.36

Worked example (male, 172 cm, medium frame):

h_{ex} = \frac{172 - 152.4}{2.54} \approx 7.7165 in

Devine: W_{kg} = (50 + 2.3 \cdot 7.7165) \cdot 1 \approx 67.7 kg

Hamwi: W_{kg} \approx 68.8 kg

Robinson: W_{kg} \approx 66.7 kg

Miller: W_{kg} \approx 67.1 kg

Average ≈ 67.6 kg; range ≈ 66.7 to 68.8 kg. Converting to pounds multiplies by 2.20462.

Units, precision & rounding

Display rounds to one decimal place for the table, chart, and CSV.
JSON output keeps full floating‑point precision from the computation.
Height may be entered in centimeters or inches; conversion uses 2.54 cm per inch.
Pound values use 2.20462 as the kilogram‑to‑pound factor.

Validation & bounds

Input validation
Field	Type	Min	Max	Step/Pattern	Error Text	Placeholder
gender	enum	—	—	male, female	—	—
heightValue	number	0	—	any	—	—
heightUnit	enum	—	—	cm, in	—	—
weightUnit	enum	—	—	kg, lb	—	—
frameSize	enum	—	—	small, medium, large	—	—

I/O formats

Input and output formats
Input	Accepted Families	Output	Encoding/Precision	Rounding
Sex, height, units, frame	Numerical and categorical	Table, chart, CSV, JSON	UTF‑8 text; JSON numbers	One decimal (table/CSV/chart); none in JSON

Networking & storage behavior

Computation and formatting are browser‑based; no data is transmitted or stored server‑side. Clipboard and file downloads occur on your device.

Assumptions & limitations

Designed for adults; not calibrated for children or pregnancy.
Below 152.4 cm, added inches are zero; only baselines apply.
Does not reflect body composition or athletic build.
Frame adjustment is a simple ±10% multiplier, not a measured trait.
Unit conversion uses fixed factors; minor rounding differences can appear.
Chart labels round to one decimal, which may hide very small gaps.
CSV uses rounded values; JSON retains unrounded numbers.
Clipboard writes can be blocked by system policy; a fallback is attempted.

Edge cases & error sources

Zero or negative height yields no result.
Very tall inputs produce large estimates outside typical ranges.
Decimal separator must be a dot; commas are not accepted.
Switching units can shift the last decimal due to rounding after conversion.
Rapid input changes may momentarily show stale chart scales.
Copy or download may fail if permissions are denied by the environment.
Extremely short heights rely entirely on each formula’s baseline.
Sex selection affects both baseline and slope constants.
JSON consumers should handle floating‑point precision limits.
Accessibility tools may read MathML differently across platforms.

Scientific context

The four named methods are long‑standing height‑based estimators identified in clinical and fitness literature: Devine (1974), Hamwi (1964), Robinson (1983), and Miller (1983), as reflected in the interface copy.

Privacy & compliance

No personal data is sent to a server. This is an informational tool and is not a medical device or financial product.

How‑to:

Ideal body weight estimation from height with clear results and unit control.

Select Male or Female.
Enter your height and choose cm or in.
Open Advanced to pick kg or lb.
Optionally set frame size to Small or Large.
Review each method, then use the average as a simple target.

Example: male, 172 cm, medium frame → average ≈ 67.6 kg (range ≈ 66.7–68.8 kg).

You are ready to compare scenarios or track progress over time.

FAQ:

Is my data stored?

No. Inputs are handled on your device, and generated files are created locally.

Clipboard and downloads may require permission.

How accurate is ideal weight?

It is a height‑based estimate. Use it as a reference alongside body composition, activity, and goals.

Different formulas produce slightly different slopes.

Which units can I use?

Height accepts centimeters or inches. Results display in kilograms or pounds.

Conversions use 2.54 cm/in and 2.20462 lb/kg.

What does the average mean?

It is the simple mean of the four methods, offered as a single target when values are close.

The range shows the lowest and highest estimates.

Why do formulas disagree?

They use different baselines and per‑inch slopes. The spread is usually small around typical heights.

Sex affects both baseline and slope.

Can I use it offline?

Yes. Once loaded, calculations and copies work without a network connection.

External libraries may need an initial load.

Does it cost anything?

No purchase is required.

Use is provided without charge.

Glossary:

Ideal body weight (IBW): A height‑based reference estimate for a healthy mass.
Baseline (b): Weight at 5 ft before adding per‑inch increments.
Slope (s): Added kilograms per inch above 5 ft.
Frame multiplier (f): Adjustment factor for smaller or larger build.
Average: Mean of the four estimates.
Range: Lowest and highest of the four estimates.

Ideal Weight Calculator

Estimated Ideal Weight

Introduction:

Technical Details:

Units, precision & rounding

Validation & bounds

I/O formats

Networking & storage behavior

Assumptions & limitations

Edge cases & error sources

Scientific context

Privacy & compliance

How‑to:

FAQ:

Glossary: