Published on September 01, 2026 • Last updated September 01, 2026
Tap a star to rate us instantly.
Ideal Body Weight (IBW) is an estimated healthy weight, calculated from a person's height and sex using one of several established clinical formulas, used as a general reference point rather than a single precise target.
Unlike a person's actual weight, Ideal Body Weight is a calculated estimate meant to represent a reasonable, healthy target based only on height and sex — no current weight input is needed. It was originally developed for clinical purposes, particularly for calculating medication dosages, where a consistent, reproducible reference weight was more useful than a patient's actual (and potentially unhealthy) weight. There is no single, universally agreed-upon IBW formula.
Several different equations — most notably Devine, Robinson, Miller, and Hamwi — were developed by different researchers across different decades, each using its own population data and assumptions. All four share a similar structure, a base weight for someone at exactly 5 feet tall, plus an additional amount for every inch above that, but the constants differ, so each formula produces a slightly different estimate for the same height. Rather than treating one formula as correct, it's more accurate to view IBW as a range spanning the results of all four methods.
Ideal Body Weight is related to, but distinct from, BMI: BMI evaluates a person's actual current weight against their height to assign a category (underweight, normal, overweight, obese), while IBW estimates a target weight independent of current weight. Neither approach accounts for muscle mass, body composition, or frame size, which is why IBW — like BMI — is best used as a general reference point alongside other measurements such as body fat percentage, not as a strict target.
Learn how Ideal Body Weight is calculated
Plain-language explainers that sit next to this tool.
Learn how headphone left/right channel reversal happens, why casual listening often misses it, and how a simple left-only then right-only test tone sequence makes it obvious.
A simple toolkit for students balancing a tight budget, shared living costs, and academic deadlines.
A spin wheel is one of the simplest ways to make an unbiased choice between multiple options. Learn how spin wheels ensure fairness and when to use one over a coin flip.
Why "current year minus birth year" gives the wrong age, the correct calendar-aware algorithm, and how leap years and February 29th birthdays are handled.
Search 244+ free tools by name, or pick a category below. Every one runs instantly in your browser — no signup, nothing to install.
