Tracking your BMI over time
One reading is a snapshot. Checking your BMI every month or two shows the trend, which matters more than any single number. Use the same scale, the same time of day and similar clothing each time. If you are changing your weight on purpose, a steady change of about 0.5–1 kg (1–2 lb) a week is what most health services recommend. Press Copy result under your result to keep a note of each reading.
Unit conversions
- 1 inch = 2.54 cm; 1 foot = 30.48 cm; 5 ft 7 in = 170.2 cm.
- 1 kg = 2.2046 lb; 1 lb = 0.4536 kg.
- 1 stone = 14 lb = 6.35 kg; 10 st 7 lb = 147 lb = 66.7 kg.
The calculator converts automatically, so you can enter whichever units you know and read your healthy weight range back in the same units.
Waist size for women
Measure halfway between your lowest rib and the top of your hip bone, after breathing out. A waist above 80 cm (31.5 in) is linked with higher risk in women, and above 88 cm (35 in) with substantially higher risk. A rule that adjusts for height is to keep your waist under half your height — 82 cm or less if you are 165 cm tall.