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Ideal Weight Calculator

Calculate your ideal weight range using 6 validated clinical formulas. Compare formulas, track your goal, and get a personalized BMI analysis.

Ideal Weight Calculator
ft in
--
Ideal Range (Avg: --)
BMI Analysis Healthy
-- AVG TARGET BMI
Under Healthy Over
Current BMI N/A
Target BMI 18.5–24.9
Ideal Wt. BMI --
Formula Comparison
Chart: formula bar chart.
Why Do These Formulas Differ?

These formulas were developed across different decades and patient populations. Hamwi (1964) was the first clinical estimate. Devine (1974) refined it for pharmaceutical use. Robinson and Miller (1983) used regression analysis. Peterson (2016) uses a modern BMI-based approach. Because each used different study populations and methods, they naturally produce slightly different results.

Ideal Weight at Adjacent Heights
HeightRobinsonMillerDevineHamwiAverage

Detailed Formula Comparison

Six established methods for estimating ideal body weight, each from a different era and methodology. Your current inputs are applied to all formulas in real time.

All Formulas at Your Height

Formula Year Result vs Average Method

Radar Comparison

Chart: radar comparison.

Which Formula Should You Use?

Average build, general health Robinson (1983)
Conservative lower-bound estimate Miller (1983)
Pharmaceutical / clinical dosing Devine (1974)
Known small or large frame Hamwi (1964)
Modern BMI-optimized approach Peterson (2016)
Understanding your healthy range BMI-Based Range

Weight Goal Tracker

Enter your current weight and see a realistic timeline to reach your ideal range. The calculator uses your ideal weight average as the target.

lbs
lbs
-- To Lose
-- Weeks
-- Months
-- Daily Calorie Change
-- Estimated Date

Projected Weight Over Time

Chart: projected weight over time.

Calorie Deficit / Surplus Guide

0.5 lb/wk −250 kcal/day -- weeks
1 lb/wk −500 kcal/day -- weeks
1.5 lb/wk −750 kcal/day -- weeks
2 lb/wk −1000 kcal/day -- weeks

A deficit exceeding 1000 kcal/day is not recommended without medical supervision. Safe weight change is 0.5–1 lb per week for most adults.

How to Use the Ideal Weight Calculator

1

Enter Your Details

Fill in the input fields with your data — imperial, metric, gender, and height. The calculator updates results instantly as you type, so there's no submit button to press.

2

Adjust Options & Presets

Fine-tune your calculation by adjusting any optional settings, presets, or advanced parameters. Try different values to compare scenarios and understand how each variable affects the outcome.

3

Review & Share Results

Read your results in the output panel. Use the Share button to generate a link with your inputs pre-filled, or copy results to your clipboard. All calculations happen locally in your browser — your data is never sent to a server.

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Frequently Asked Questions

Basics Which ideal weight formula is most accurate?
There is no single "perfect" formula. Robinson is most cited for general populations. Hamwi is preferred when frame size is clearly small or large. Peterson (2016) is the most modern approach. Our average across all formulas provides the most balanced estimate.
Basics How do I determine my frame size accurately?
Wrap your thumb and middle finger around your opposite wrist. If they overlap, you have a small frame. If they touch, you have a medium frame. If there is a gap, you have a large frame. Frame size adjusts your ideal weight range by approximately 10%.
Basics Does this account for muscle mass? What is FFMI?
Standard height-based formulas do not account for muscle mass. Switch to Athletic mode and enter your body fat % to calculate your Fat-Free Mass Index (FFMI) — a far better indicator for active individuals. An FFMI of 18–20 is average, 22–24 is excellent, and 25+ is elite.
Basics What is the Peterson (2016) formula?
Peterson et al. proposed using BMI 22 as the reference point for ideal weight: Weight (kg) = 22 × height(m)². This modern approach avoids the "inches over 60" limitation and works better for heights far from 5 ft.
Basics Why does age matter for weight calculations?
Clinical guidelines suggest adults 65 and older benefit from a slightly higher BMI target (22–27) for longevity. For users 40+, muscle mass declines roughly 1% per year (sarcopenia). The calculator adjusts the BMI target range accordingly.
Advanced How does the Goal Tracker work?
Enter your current weight in the Goal Tracker tab. It calculates the difference to your ideal range, then shows projected weight loss/gain over time at your chosen rate. The chart visualizes your journey week by week, with estimated completion dates and daily calorie adjustments.
Advanced Can these formulas be used for children?
No. All formulas here are strictly for adults 18+. Children and adolescents should use age-and-gender-specific BMI percentile charts to track healthy development.
Advanced Is "Ideal Weight" different from "Healthy Weight"?
"Healthy Weight" refers to the broad BMI range of 18.5–24.9. "Ideal Weight" formulas attempt to find the optimal midpoint where statistical mortality risk is lowest. Our average is generally near BMI 21–22 for most adults.

Formulas & Methods

Value

input.value.replace(/[^\d.]/g, '')

To D

function (kg) { return unit === 'imperial' ? kg * 2.20462 : kg

Total Diff

Math.abs(currentKg - targetKg)

Key Terms

ImperialAn input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.
MetricAn input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.
GenderAn input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.
HeightAn input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.
Height (cm)An input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.
AgeAn input parameter used in ideal weight calculations. Adjust this value to see how it affects your results.

Real-World Examples

AL

Alex

28-year-old software engineer starting a fitness journey

Imperial
Moderate
Metric
Moderate
Gender
Female
Height
5 ft 8 in
Sample outcome
Target range identified

Try entering Alex's values above to see the detailed breakdown.

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Finding Your Ideal Weight

The concept of an ideal body weight has evolved significantly since the first actuarial tables were published in the 1940s. Modern clinical formulas attempt to estimate the weight at which a given height correlates with the lowest mortality risk and best overall health outcomes.

Why Six Formulas?

Each formula was developed from different populations and datasets. Robinson and Miller used updated regression analyses. Devine originally created his formula for pharmaceutical dosing. Hamwi provided the simplest rule of thumb. Peterson (2016) took a modern BMI-centered approach, and the BMI-based range shows the full healthy window. By comparing all six, you get the most complete picture of where your ideal weight lies.

Beyond the Number

Ideal weight formulas cannot distinguish between muscle and fat. A person with significant muscle mass may exceed the formula range while having excellent health markers. This is why Athletic mode uses FFMI instead. For most people, the standard mode gives a reasonable target range.

Practical Application

Use the ideal weight range as a long-term directional guide rather than a precise target. Focus on trends in body composition, energy levels, and health biomarkers. A weight that allows you to maintain consistent energy, sleep well, exercise comfortably, and sustain healthy blood markers is your personal ideal.