BMI change over time

Your BMI then, your BMI now and the gap between them. Useful after a few months of changes, or for reading old GP letters.

Your details

Your BMI has moved by

-1.3

From 27.8 to 26.5

Then27.8, overweight
Now26.5, overweight
One BMI point at your height6.2 lb
Weight change-4.7% of your starting weight
Over timeadd the months between the weights for a monthly rate
A BMI to aim foradd one to see the weight it means at your height

Same band as before. Bands are wide, so small changes can matter without moving you between them.

Over time

Rate and milestones

Add the months between the two weights for a rate. At 168 cm, going from 78 kg to 72 kg over 6 months is 0.4 BMI points a month and about 0.2 kg a week, gentler than the NHS pace of 0.5 to 1 kg a week. It is also 7.7% of the starting weight, past the 5% that NICE links with real health benefits.

One point

What one BMI point weighs

One BMI point is your height in metres, squared, in kilos. At 5 ft 6 in (1.676 m) that is 1.676 × 1.676 = 2.8 kg, or about 6 lb. Taller people need a bigger change to move one point.

The working

Then and now

12 st 4 lb is 78.0 kg, so BMI then = 78.0 ÷ 2.81 = 27.8. 11 st 10 lb is 74.4 kg, so BMI now = 26.5. That is a fall of 1.3 points, still in the overweight band but heading the right way, if that is the way you wanted.

A BMI to aim for

What it means in weight

Weight at any BMI is that BMI × your height in metres, squared. At 168 cm (2.82 m²), a BMI of 25 is 70.6 kg; from 72 kg that is 1.4 kg more, which at the 1 kg a month of the example above is about 1.4 months. For South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean backgrounds, NICE NG246 starts overweight at 23 and obesity at 27.5, so pick your background for the right bands.

Bands are wide

Why your band may not change

Each band is 5 points wide, which is 14 kg (over 2 stone) at an average height. You can make a real difference to blood pressure and blood sugar without crossing a line, so watch the number, not just the label.

Questions

Common questions

How much weight is one BMI point?

Your height in metres squared, in kilos. About 2.6 kg at 5 ft 4 in, 3.0 kg at 5 ft 8 in and 3.3 kg at 6 ft.

Does BMI change with age if my weight stays the same?

No, the sum only uses height and weight. But many people lose a little height after 60, which nudges BMI up slightly.

How often should I check my BMI?

Every few months is plenty. Weekly changes are mostly water.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

If your weight is on your mind

Talk to your GP if your weight has changed a lot without trying, or if it is worrying you. If food or your body feels hard to think about, Beat has a free helpline on 0808 801 0677 (England, weekdays 3pm to 8pm).