How to measure your waist and hips
Use a flexible, non-stretch tape. Stand with feet together, weight shared evenly and arms relaxed. Keep the tape level around the body and snug without pressing into the skin. Measure directly on skin where practical, or over light clothing.
For the waist, locate the lower edge of the last rib you can feel and the top of the hip bone at your side. Place the tape halfway between these landmarks, not automatically at the navel or trouser waistband. Read it after breathing out normally. For the hips, use the largest circumference around the buttocks, below the top of the hip bone. The diagram shows locations, not a body shape to aim for.
How to use the calculator
Enter both circumferences and select the unit for each one. The inputs can use different units. Changing a unit converts your own value, displayed with up to two decimals (significant digits for very small values). Faint examples switch to 32 inches for the waist and 40 inches for the hips. Select Calculate to confirm the ratio and the two values converted to centimetres.
The faint examples work immediately. Focusing an example clears that field; leaving it empty restores the example without restoring a previous result. Actual entries are preserved.
Formula and worked examples
Waist-to-hip ratio = waist circumference ÷ hip circumference, after converting both to the same unit. One inch is exactly 2.54 cm. The ratio has no unit: 80 cm ÷ 100 cm = 0.8. It means the waist measurement is 0.8 times the hip measurement.
32 inches ÷ 40 inches also equals 0.8. Mixed units work too: a waist of 30 inches is 76.2 cm; with hips of 100 cm the ratio is 0.762, displayed as 0.76. Ordinary ratios show up to two decimals; very small ratios keep significant digits rather than becoming zero.
What the number does and does not mean
This is a comparison of two tape measurements. It does not measure body fat or diagnose disease, and it gives no normal-weight, attractiveness or weight-loss judgement. No sex or age is needed for the arithmetic.
Different measuring sites can change the result. Use the same landmarks and tape position if comparing measurements taken on different days. The accepted 0.1–500 cm input range is a numeric guardrail, not a typical or recommended body-size range.
Questions and answers
Why does the result look unexpected?
Check that waist and hip have not been swapped, that each unit is correct, and that you entered a circumference rather than a width. Use a decimal point or comma without thousands separators. Zero, negative values and missing measurements cannot produce a valid ratio.
Copying and clearing
Copy result includes the ratio and converted measurements. Editing a field or unit clears the confirmed result and disables copying until the next calculation. Clear removes entries and retains unit choices. Inputs are processed here in your browser; this calculator does not upload them.