How to measure your height and weight accurately

By Haris Asif · Published October 4, 2026

Good measurements make every calculation that follows more reliable. A few habits make home measurements much more consistent.

Measuring height

1. Use a flat, hard wall and a floor without carpet, if possible.
2. Stand barefoot with heels together and against the wall. Let your arms hang naturally.
3. Look straight ahead. Your chin should be level, not tilted up or down.
4. Mark the top of your head using a flat object such as a hardcover book held level against the wall. Have someone else make the mark.
5. Measure from the floor to the mark with a rigid tape measure, and write down the number in the units you measured.

Height changes slightly through the day. People are usually a little taller in the morning, so measure at a similar time if you want to compare results.

Measuring weight

• Put the scale on a hard, flat floor rather than carpet.
• Weigh yourself at a similar time of day, ideally before eating and after using the bathroom.
• Wear light clothing or none, and stay consistent.
• Stand still with your weight evenly spread until the reading settles.

Small day-to-day changes are normal and mostly reflect water, food and salt. Looking at a trend over weeks is more informative than any single reading.

Converting your measurements

Many forms and tools accept only one system. You can convert in a few seconds:

• Height: use the Height Converter. For example, 5 ft 11 in is 71 inches, and 71 × 2.54 = 180.34 cm.
• Weight: use the Weight Converter. For example, 150 lb is 150 × 0.45359237 = 68.04 kg.

Using the numbers

Once you have height and weight, the BMI Calculator accepts either system. Remember that BMI is only a general screening number. See how BMI is calculated and what it can and cannot tell you.

If you are measuring a child, use the child’s doctor or school nurse. Growth is assessed against age and sex charts rather than adult categories.

Keep a simple log

If you want to track changes, write the date, the time of day and the units each time. A small notebook or spreadsheet is enough. Always record the units, because mixing kilograms and pounds in the same list is a common cause of confusing results.