What does a BMI of 18.5 mean?
A BMI of 18.5 is at the bottom of the healthy range for adults (18.5–24.9). Just below it, BMI is in the underweight range. 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:
If you’re worried about eating or your weight, free and confidential support is available from ANAD.
Under 20? BMI works differently for kids and teens.
Use the Kids & Teens calculator →
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What a BMI of 18.5 means
18.5 is where the healthy range starts, with both the standard and the lower cut-offs. A BMI under 18.5 is classed as underweight.
A low BMI can have many causes, from a naturally slim build to illness or not eating enough. If you’ve lost weight without trying, talk to a doctor. If you’re worried about eating or your weight, free and confidential support is available from ANAD.
Weight at a BMI of 18.5 by height
The weight at a BMI of 18.5 is the lowest healthy weight at each height.
| Height | Weight at a BMI of 18.5 | Healthy weight |
|---|---|---|
| 5′0″ (152 cm) | 95 lb (43 kg) | 95–127 lb (43–57 kg) |
| 5′2″ (157 cm) | 101 lb (46 kg) | 101–136 lb (46–61 kg) |
| 5′4″ (163 cm) | 108 lb (49 kg) | 108–145 lb (49–65 kg) |
| 5′6″ (168 cm) | 115 lb (52 kg) | 115–154 lb (52–70 kg) |
| 5′8″ (173 cm) | 122 lb (56 kg) | 122–164 lb (56–74 kg) |
| 5′10″ (178 cm) | 129 lb (59 kg) | 129–173 lb (59–78 kg) |
| 6′0″ (183 cm) | 137 lb (62 kg) | 137–183 lb (62–83 kg) |
| 6′2″ (188 cm) | 144 lb (66 kg) | 144–194 lb (66–88 kg) |
| 6′4″ (193 cm) | 152 lb (69 kg) | 152–204 lb (69–92 kg) |
Each weight is the lowest whole pound or kilogram that gives a BMI of 18.5 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.