What Is a Healthy Weight for Your Height? The Truth Behind the Numbers
There is no single number that represents a healthy weight for your height. There are ranges — and within those ranges, several formulas that produce subtly different answers, none of which tells you anything about your body fat percentage, muscle mass, bone density, or metabolic health. Yet the question "what should I weigh?" is one of the most searched health queries on the internet.
The answer is more nuanced than most weight charts admit — but it's also more actionable than people assume. Here's how doctors actually estimate healthy weight ranges, why those estimates vary by formula, and why what you measure alongside your weight matters more than the number on the scale.
The Four Ideal Weight Formulas
Physicians use several different formulas to estimate ideal body weight (IBW), originally developed for clinical settings — particularly for calculating drug dosages in patients. None was designed as a personal health verdict, but all have been repurposed as rough benchmarks for weight discussions.
Hamwi Formula (1964)
The Hamwi formula, developed by Dr George Hamwi, remains one of the most widely taught in medical education:
Men: 106 lbs + 6 lbs per inch above 5 feet
Devine Formula (1974)
Dr B.J. Devine originally published these equations for predicting creatinine clearance — they were never intended as weight targets — but they became widely adopted:
Men: 50 kg + 2.3 kg per inch above 5 feet
Robinson Formula (1983)
A refinement of the Devine formula, published by Dr J.D. Robinson:
Men: 52 kg + 1.9 kg per inch above 5 feet
Miller Formula (1983)
Another revision, published by Dr D.R. Miller in the same year:
Men: 56.2 kg + 1.41 kg per inch above 5 feet
Key Insight
All four formulas were developed primarily using data from white American and European male populations in clinical or military settings. They were never validated as universal health targets across different sexes, ages, or ethnic backgrounds. Use them as rough starting points — not precise prescriptions.
Worked Example: A 5'7" (170 cm) Woman
Height 5'7" = 7 inches above 5 feet. Running the four formulas:
| Formula | Calculation | Result |
|---|---|---|
| Hamwi | 100 + (5 × 7) | 135 lbs / 61.2 kg |
| Devine | 45.5 + (2.3 × 7) | 61.6 kg / 135.8 lbs |
| Robinson | 49 + (1.7 × 7) | 60.9 kg / 134.2 lbs |
| Miller | 53.1 + (1.36 × 7) | 62.6 kg / 138 lbs |
| Average | — | 61.6 kg / 135.7 lbs |
The range across all four formulas is just 3.7 kg (8 lbs) — they broadly agree. What they produce is a midpoint estimate, not a target. A healthy range for this person would typically be considered 56–68 kg (123–150 lbs), corresponding to a BMI of 19.4–23.5.
The Ideal Weight Calculator runs all four formulas simultaneously for your height and sex, showing the range alongside a BMI-based reference band.
Why BMI Alone Is Incomplete
BMI (Body Mass Index) — weight in kg divided by height in metres squared — is the most widely used population screening tool for weight-related health risk. The WHO defines these ranges for adults:
| BMI | Category |
|---|---|
| Below 18.5 | Underweight |
| 18.5 – 24.9 | Normal / Healthy weight |
| 25.0 – 29.9 | Overweight |
| 30.0 and above | Obese |
The problem: BMI measures weight relative to height — not body composition. It cannot distinguish between muscle and fat.
Consider two people, both 5'11" (180 cm) and 95 kg (209 lbs). Their BMI is identical at 29.3 — "Overweight" — but:
- Person A is a competitive cyclist with 11% body fat, excellent cardiovascular fitness, and high muscle mass.
- Person B is sedentary, carries most weight around the abdomen, and has elevated blood glucose markers.
BMI treats them identically. They are not remotely similar health situations. For a deeper exploration of what BMI does and doesn't measure, see the companion guide What Is a Healthy BMI?.
The BMI Calculator gives you your number instantly in both metric and imperial — but always interpret it alongside the other markers below.
⚠️ Ethnic Variations in BMI Risk
The standard BMI categories were established using primarily European population data. For people of South Asian, East Asian, or Southeast Asian descent, health risk associated with excess body fat begins at lower BMI values — roughly BMI 23 for "overweight" risk rather than 25. The WHO issued adjusted recommendations for Asian populations in 2004. If you are of Asian descent, discuss appropriate thresholds with your doctor rather than using the standard Western cut-offs.
Better Measures to Use Alongside Weight
No single number captures health fully. For a more complete picture, combine weight with:
Body Fat Percentage
Body fat percentage distinguishes between muscle and fat — the information BMI lacks entirely. Healthy ranges (approximate):
| Women | Men | |
|---|---|---|
| Athletic | 14–20% | 6–13% |
| Healthy | 21–33% | 8–19% |
| Overweight | 34–39% | 20–24% |
| Obese | 40%+ | 25%+ |
The Body Fat Calculator estimates body fat percentage using skinfold measurements (Jackson/Pollock method) or body circumference measurements — no lab equipment needed.
Waist Circumference
Where fat is stored matters as much as how much. Visceral fat — stored around the abdominal organs — is far more metabolically dangerous than subcutaneous fat stored under the skin. Waist circumference is a practical proxy for visceral fat.
WHO targets for reduced metabolic risk:
- Women: under 80 cm (31.5 in)
- Men: under 94 cm (37 in)
Above these thresholds, cardiovascular and diabetes risk rise significantly regardless of BMI.
Basal Metabolic Rate (BMR)
Your BMR — the calories your body burns at complete rest — is tied to your body composition and gives context to your energy needs. The BMR Calculator calculates yours using the Mifflin-St Jeor equation, which is more accurate than the older Harris-Benedict formula. From BMR, the Daily Calorie Calculator adds your activity level to give your total daily energy needs — the real starting point for any weight management plan.
What To Actually Do With Your Number
Here's the practical guidance most ideal weight articles skip:
If you're within the healthy range: The formulas have done their job — you're in a broadly low-risk zone for weight-related health conditions. Now focus on the things the scale doesn't measure: body fat percentage, cardiovascular fitness, diet quality, blood pressure, and blood glucose. A "healthy" weight with a sedentary lifestyle and poor diet still carries risk.
If you're above the healthy range: The formulas and BMI give a signal worth taking seriously — but the signal is imprecise. A 10 kg gap above formula ranges looks very different on an active, muscular person versus someone sedentary with high visceral fat. Get a body fat assessment and a waist measurement. Talk to a doctor. A weight loss timeline based on a realistic calorie deficit, not a crash approach, is far more sustainable: the Weight Loss Timeline Calculator shows how long a modest deficit takes to reach any goal weight.
If you're below the healthy range: Low weight carries its own serious risks — malnutrition, bone density loss, hormonal disruption, and immune suppression. This end of the scale is often underemphasised in popular health coverage, but clinically it's just as significant. If your weight is below healthy ranges, discuss it with a healthcare provider.
💡 Focus on the Trend, Not the Number
Body weight fluctuates by 1–3 kg / 2–6 lbs throughout a single day depending on food, water, and digestion. Weigh yourself once per week at the same time (morning, after using the bathroom) and track the weekly average over 4–8 weeks — that trend tells you far more than any single reading. A consistently downward average over 6 weeks is meaningful. A single "bad" number on the scale after a large meal is not.
Frequently Asked Questions
Which ideal weight formula is the most accurate?
None of the four formulas is definitively most accurate — they were all developed for specific clinical purposes, not as personal weight targets. The Devine formula is the most widely referenced in medical literature; the Hamwi is the most intuitive to calculate. In practice, the range produced across all four formulas (typically 3–5 kg) is more useful than any single formula's output. The Ideal Weight Calculator shows all four results simultaneously alongside a BMI-based range.
Do ideal weight formulas apply to older adults?
With significant caveats. Adults naturally lose muscle mass (sarcopenia) and gain fat from their 30s onward, but the weight-height relationship in the formulas doesn't adjust for age. An older adult who appears to be at a "healthy" weight by formula may have lost significant muscle mass that the scale doesn't reveal. Body fat percentage and functional fitness (strength, balance, cardiovascular endurance) are more meaningful health indicators for adults over 60 than weight targets alone.
Is there a healthy weight formula for children?
Not a simple height-based formula — children's healthy weight is assessed using age- and sex-specific BMI percentile charts rather than fixed formulas, because body composition changes dramatically throughout childhood and adolescence. A paediatrician interprets a child's BMI alongside their growth chart over time, not as a snapshot number. The adult formulas in this article should never be applied to children.
Can I be healthy at a weight above the formula range?
Yes — particularly if the extra weight is primarily muscle. A competitive powerlifter or rugby player will typically be well above formula ranges while having excellent metabolic health, low body fat, and strong cardiovascular function. For non-athletes, however, weight above the formula range usually indicates elevated health risk, especially if accompanied by high waist circumference. Body fat percentage is the most objective way to distinguish high-muscle "heavy" from high-fat "heavy."
How long does it realistically take to reach a healthy weight?
A sustainable rate of weight loss is typically 0.3–0.7 kg (0.7–1.5 lbs) per week — faster rates risk muscle loss and are difficult to sustain. At 0.5 kg/week, a 10 kg loss takes about 20 weeks (5 months). The Weight Loss Timeline Calculator shows your personal projected date based on your starting weight, goal weight, and chosen deficit. For weight gain (building muscle), a 0.2–0.5 kg/month rate minimises fat accumulation while supporting muscle growth.
Find Your Healthy Weight Range
Stop chasing a single target number — start working with a realistic range and the metrics that matter. Use the Ideal Weight Calculator to see all four formula estimates for your height and sex, then layer in the BMI Calculator and Body Fat Calculator for a complete picture of where you are and what realistic progress looks like.
