Ideal Body Weight Calculator (IBW)

Use the Ideal Body Weight Calculator (IBW)

Enter height and sex to see IBW by Devine, Robinson, Miller, and Hamwi, plus a healthy BMI‑based range. Adjust frame size (±10%) to reflect build.

How to Use Ideal Body Weight Calculator (IBW)

1. Step 1: Select Units

   Choose Metric (cm) or US (ft/in) so the ideal body weight calculator displays familiar inputs.

2. Step 2: Pick Sex

   Select male or female. IBW formulas are sex-specific and use different constants.

3. Step 3: Enter Height

   Type your height. Results update instantly; no need to press calculate.

4. Step 4: Adjust Frame (Optional)

   If you have a small or large frame, apply ±10% to the average IBW.

5. Step 5: Compare Results

   Review Devine, Robinson, Miller, and Hamwi estimates and the healthy BMI range.

Key Features

• Devine/Robinson/Miller/Hamwi formulas
• Sex-specific IBW targets
• Frame size adjustment (±10%)
• Metric & US units
• Healthy BMI range for height
• Mobile-first, instant results

Understanding Results

Formula

This tool shows four ideal body weight (IBW) estimates that all follow the same idea: start with a baseline weight at 5 ft (60 in) and add or subtract a fixed amount for each inch of height. We include Devine, Robinson, Miller, and Hamwi. The average of these four often serves as a practical midpoint.

Optionally, you can adjust the average for frame size using a simple rule of thumb: −10% for small frames, +10% for large. This reflects how bone structure and build can shift a comfortable target.

Reference Ranges & Interpretation

Alongside IBW, we show a healthy weight range derived from BMI 18.5–24.9 for your height. If your current weight sits above the IBW average but within the healthy range, you may simply carry more lean mass. If you are below both IBW and the healthy range, you may want to review fueling and training with a qualified professional.

For a full BMI breakdown, use the Adult BMI Calculator. For composition, try the Body Fat Percentage and Lean Body Mass calculators — they provide extra context that IBW alone cannot show.

Assumptions & Limitations

IBW formulas are designed for typical adults. They do not directly account for age, ethnicity, pregnancy, or athletic musculature beyond the basic frame-size adjustment. Treat IBW as guidance, not a diagnosis. Clinical use (e.g., drug dosing) should follow local protocols and professional judgment.

Complete Guide: Ideal Body Weight Calculator (IBW)

Find your IBW with the ideal body weight calculator (IBW calculator) using Devine, Robinson, Hamwi, and Miller formulas. Adjust for height, sex, and frame size.

This ideal body weight calculator shows results from four respected formulas and a frame‑size adjustment, then compares them with a healthy BMI‑based weight range for your height. It is designed to be quick to use on any device, with clean labels, large touch targets, and instant updates.

What is ideal body weight (IBW)?

Ideal body weight (IBW) is a height‑based estimate of what someone might weigh if they had a typical body composition for their sex. IBW is not a medical diagnosis; it is a practical reference used in clinical settings (for example, to estimate dosing weight) and in fitness contexts to set baseline expectations. Because everyone’s body composition varies, IBW is best treated as a target zone rather than a strict goal.

In this calculator, you’ll see IBW from four common formulas (Devine, Robinson, Miller, and Hamwi). We also show a healthy weight range derived from Body Mass Index (BMI 18.5–24.9) as an additional reference. If you want a full BMI check with category labels, see the Adult BMI Calculator.

How this ideal body weight calculator works

Enter your height, select your sex, and optionally choose a frame size (small, medium, or large). The tool calculates four IBW estimates and highlights their average. If you select a small or large frame, we apply a ±10% adjustment to that average — a simple, widely used rule of thumb to reflect bone structure and build.

You’ll also see a healthy weight range for your height. That range uses BMI boundaries of 18.5 and 24.9. For a dedicated range tool with more context, open the Healthy Weight Range Calculator.

IBW formulas explained (clear, comparable, and practical)

Many IBW formulas were originally developed for adults to support medication dosing or to populate reference tables. While the constants differ, the logic is the same: start with a baseline weight at 5 ft (60 in) and add or subtract a set amount per inch above or below that height. Below are the four formulas we include, shown in plain English for readability.

Choosing among formulas: when each helps

If you want a single anchor, Devine is the most commonly cited in clinical dosing. Robinson trends slightly lighter at taller heights and can be a conservative choice when you prefer the low end of a target. Miller often sits in the middle and reassures you that the range is stable, while Hamwi is a classic table value many people recognize. Looking at all four side‑by‑side prevents over‑reliance on any one constant and keeps the conversation grounded in a realistic band rather than a fixed point.

Devine formula: widely used in clinical dosing

The Devine equation is popular in pharmacy and anesthesia to estimate dosing weight. In kilograms, the formula is:

• Male: 50 kg + 2.3 kg × (height in inches − 60)
• Female: 45.5 kg + 2.3 kg × (height in inches − 60)

Because Devine is entrenched in clinical practice, it is a useful anchor for comparison. In our results, it tends to sit near the middle of the pack for many heights.

Robinson formula: a lighter estimate than Devine

• Male: 52 kg + 1.9 kg × (height in inches − 60)
• Female: 49 kg + 1.7 kg × (height in inches − 60)

Robinson generally yields a slightly lower IBW than Devine at taller heights, which can be helpful when you want a conservative estimate. Our calculator shows it alongside the other methods so you can see differences at a glance.

Miller formula: a balanced middle ground

• Male: 56.2 kg + 1.41 kg × (height in inches − 60)
• Female: 53.1 kg + 1.36 kg × (height in inches − 60)

Miller often lands between Devine and Hamwi. Seeing its value next to the others can reassure you that your results are consistent across reasonable methods.

Hamwi formula: a classic from clinical tables

• Male: 48.0 kg + 2.7 kg × (height in inches − 60)
• Female: 45.5 kg + 2.2 kg × (height in inches − 60)

Hamwi is sometimes a touch higher than Robinson and can be closer to Devine. It originated in an era of paper charts and remains a recognizable reference in many guides.

Frame size: small, medium, or large?

People with smaller bone structures and narrower builds may find typical IBW numbers feel a bit high; larger‑framed people may feel the opposite. A practical rule used for decades is a ±10% adjustment to the IBW average. Our calculator applies this when you pick Small (−10%) or Large (+10%). If you’re unsure about your frame size, you can get a quick estimate using our Frame Size Calculator and then return to this page.

Worked examples (to make numbers concrete)

Numbers are easier to understand with context. Below are two quick scenarios that illustrate how IBW, frame adjustments, and the BMI range come together. Your own results will differ based on your exact height and selections.

Example A — 5′4″ (163 cm) female, medium frame

• Devine ≈ 54.7 kg, Robinson ≈ 52.6 kg, Miller ≈ 52.3 kg, Hamwi ≈ 50.4 kg
• Average ≈ 52.5 kg (≈ 116 lb); small frame ≈ 47.3 kg, large frame ≈ 57.8 kg
• Healthy BMI range for height ≈ 49.1–66.1 kg

Example B — 5′10″ (178 cm) male, large frame

• Devine ≈ 75.3 kg, Robinson ≈ 72.6 kg, Miller ≈ 73.8 kg, Hamwi ≈ 74.7 kg
• Average ≈ 74.1 kg (≈ 163 lb); large‑frame adjusted ≈ 81.5 kg
• Healthy BMI range for height ≈ 61.0–82.3 kg

In both cases, the IBW average sits comfortably inside the healthy BMI range, and the frame adjustment nudges the target up or down in a way that often aligns with how people naturally feel at different weights.

IBW vs. BMI vs. body fat: which should you use?

Each measurement tells you something slightly different. IBW offers a height‑and‑sex‑based target often used in clinical contexts. BMI categorizes your current weight relative to height, which is helpful for population screening but doesn’t directly measure fat. Body fat percentage estimates composition — the split between fat mass and lean mass — which can be more informative for athletes and lifters.

• Check your current category with the Adult BMI Calculator.
• Estimate body composition with the Body Fat Percentage Calculator and Lean Body Mass Calculator.
• Assess central adiposity risk with the Waist‑to‑Height Ratio Calculator.

For long‑term planning (nutrition, training, and health), it helps to look at IBW, BMI, and body fat together. If you prefer energy‑based planning, consider your calorie needs via the BMR Calculator, TDEE Calculator, or Maintenance Calorie Calculator.

How to use your result (practical tips)

Treat IBW as an informative benchmark — not a verdict on your health. If your current weight is above the IBW average but within the healthy BMI range, your composition may simply include more lean mass. If your weight is below the IBW average and outside the healthy range, you may want to discuss fueling and training with a clinician or registered dietitian.

Choosing a sustainable target (step‑by‑step)

1. Start with the IBW average from this page and note the healthy BMI range.
2. Pick the midpoint of that healthy range as a fallback target if your composition is unknown.
3. Estimate body fat and lean mass using the Body Fat Percentage Calculator and Lean Body Mass Calculator.
4. Translate the target into daily energy using the Maintenance Calorie Calculator or TDEE Calculator.
5. Plan macros or protein if helpful: try the Protein Calculator or Macro Calculator.
6. Review progress every 2–4 weeks and adjust in small steps (±100–200 kcal/day).

• Use the IBW average to set an initial target, then refine it with body fat estimates.
• Focus on trend lines (weekly averages), not single‑day weigh‑ins.
• Pair weight targets with sustainable habits: adequate protein, resistance training, daily movement, and sleep.
• Consider the Calorie Deficit Calculator if your goal is fat loss, or the Weight Gain Calculator if you’re building mass.

Limitations and cautions

IBW formulas are statistical estimates. They do not account for age‑related changes, ethnicity‑specific differences, or individual variation in skeletal structure and muscularity beyond the frame‑size adjustment. They are not designed for children, pregnant people, or elite athletes with unusually high lean mass.

In clinical settings, IBW may be used to estimate drug dosing weight or to calculate adjusted body weight (ABW) when someone’s actual weight significantly exceeds IBW. Those choices are protocol‑specific and should always follow local guidelines. When in doubt, speak with a licensed professional.

Common myths and facts about IBW

• Myth: IBW is the only healthy weight for a person. Fact: IBW is a reference point; many healthy adults sit above or below it depending on build and muscle mass.
• Myth: All formulas should match exactly. Fact: Methods differ slightly by design. Looking at several side‑by‑side helps you see a realistic band.
• Myth: IBW applies to kids and pregnancy. Fact: IBW formulas were created for typical adults. Use dedicated pediatric and prenatal tools instead.
• Myth: BMI and IBW are interchangeable. Fact: BMI describes current weight status; IBW estimates a height‑based target.

References

• Centers for Disease Control and Prevention (CDC). About Adult BMI. cdc.gov
• National Institutes of Health (NIH). Consider general adult BMI context from MedlinePlus: Body mass index (BMI).
• Devine BJ (1974), Robinson JD (1983), Miller DR (1983), and Hamwi GJ (1964) formulas as summarized in standard clinical references.

Frequently Asked Questions