What does a BMI of 40 mean?
A BMI of 40 or more is far above the healthy range for adults (18.5–24.9): it’s obesity, class 3, sometimes called severe obesity. It’s a screening number, not a diagnosis.
For adults 20+ · Based on CDC & WHO guidelines · Updated
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Your BMI
Healthy weight for your height: –
Your result and the healthy range for your height will appear here.
Waist-to-height ratio:
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What a BMI of 40 means
At this level, BMI is a much more reliable sign of excess body fat: the 2025 Lancet commission on clinical obesity notes that excess fat can reasonably be assumed at a BMI above 40. A doctor can help you look at your overall health and the options available.
How far 40 is from the healthy range
At common heights: the weight at a BMI of 40, and how far it is above the top of the healthy range.
| Height | Weight at a BMI of 40 | Healthy weight | Above the healthy range by |
|---|---|---|---|
| 5′0″ (152 cm) | 205 lb (93 kg) | 95–127 lb (43–57 kg) | 78 lb (36 kg) |
| 5′2″ (157 cm) | 219 lb (100 kg) | 101–136 lb (46–61 kg) | 83 lb (39 kg) |
| 5′4″ (163 cm) | 233 lb (106 kg) | 108–145 lb (49–65 kg) | 88 lb (41 kg) |
| 5′6″ (168 cm) | 248 lb (113 kg) | 115–154 lb (52–70 kg) | 94 lb (43 kg) |
| 5′8″ (173 cm) | 263 lb (120 kg) | 122–164 lb (56–74 kg) | 99 lb (46 kg) |
| 5′10″ (178 cm) | 279 lb (127 kg) | 129–173 lb (59–78 kg) | 106 lb (49 kg) |
| 6′0″ (183 cm) | 295 lb (134 kg) | 137–183 lb (62–83 kg) | 112 lb (51 kg) |
| 6′2″ (188 cm) | 312 lb (142 kg) | 144–194 lb (66–88 kg) | 118 lb (54 kg) |
| 6′4″ (193 cm) | 329 lb (149 kg) | 152–204 lb (69–92 kg) | 125 lb (57 kg) |
Each weight is the lowest whole pound or kilogram that gives a BMI of 40 on the calculator. Select a height for its healthy weight page.
What to do next
- Check your waist-to-height ratio. It shows whether weight is carried around the middle, which BMI can’t.
- See the healthy weight for your height.
- Talk to a doctor if your BMI is outside the healthy range, or if your weight has changed without you trying.