#1450 · Health Tool

Monthly BMI Calculator

Track monthly BMI movement from height, starting weight, ending weight, and target weight to judge progress direction.

Calculator

Monthly BMI inputs
m
kg
kg
kg
Ad space

How to use this calculator

  • Enter height in meters.
  • Enter starting and ending body weight.
  • Enter target weight.
  • Calculate to compare BMI change and target gap.

What the result means

The result shows BMI movement and whether your monthly weight change is moving toward your target at a sustainable pace.

BMI = weight ÷ height². BMI change = ending BMI - starting BMI. Target gap = ending weight - target weight.

BMI does not measure body composition. Muscular users may need body fat tracking too.

Example calculation

At 1.75m, 80kg gives BMI 26.1 and 78kg gives BMI 25.5, a monthly BMI change of -0.65.

Tips for better results

  • Use BMI with body fat or waist measurements when possible.
  • Avoid extreme monthly weight swings.
  • Focus on direction and sustainability.
  • Remember that BMI categories are broad ranges.

FAQ

How do I calculate BMI change over a month?

Calculate BMI at the start and end of the month, then subtract starting BMI from ending BMI.

Can BMI go down even if body fat does not change much?

Yes. BMI only uses height and weight, not body composition.

What monthly BMI change is considered sustainable?

A gradual BMI change caused by moderate weight change is usually more sustainable.

Why does my BMI category not change after losing weight?

BMI categories cover ranges, so small weight changes may not cross a category boundary.

Should I use BMI or body fat percentage for monthly tracking?

Use both if possible. BMI tracks weight status while body fat gives composition context.

BMI categories

MetricMeaning
UnderweightBMI below 18.5.
NormalBMI 18.5 to 24.9.
OverweightBMI 25 to 29.9.
ObesityBMI 30 or higher.

Browse more calculators

Category hubs