Free · Body measurements calculators 📏

Percentage of Starting Weight Lost

Relate starting weight, current weight and a positive decrease.

  • Formula & worked example
  • Private in your browser
  • No signup
Go to tool

Calculator inputs

Loading calculator…

How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.

Formula and method

Starting at 100 kg and reaching 90 kg gives a decrease of 10 kg, equal to 10% of starting weight.

Loss = starting − current weight; loss percentage = 100 × loss / starting weight.

Worked example

Enter these known values and leave the other values blank.

Past weight
100 kg
Current weight
90 kg
Total weight loss
10 kg
Weight loss percentage
10 %

Assumptions and limitations

  • This retained model covers positive weight loss only: both weights must be positive and current weight below starting weight. It does not assess whether loss is desirable or recommend a rate.
  • Use the displayed units and measurements from the same context. Editable fields support arithmetic inverses when enough independent values are supplied. Clear a preset value before solving it as an unknown.
  • This tool performs the stated arithmetic model. It does not establish a diagnosis, prescribe treatment or replace laboratory and clinical assessment.

Common questions

What does this calculation represent?

This retained model covers positive weight loss only: both weights must be positive and current weight below starting weight. It does not assess whether loss is desirable or recommend a rate.

Can I solve for a different field?

Clear the unknown field and enter enough independent values in the remaining editable controls. A relationship cannot recover a unique value when a dividing quantity is zero.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

Explore body measurements calculators 📏 or browse all health calculators.