Clothing Size Calculator Formula

Understand the math behind the clothing size calculator. Each variable explained with a worked example.

Formulas Used

US Size (approximate)

us_size_out = us_size

UK Size (approximate)

uk_size_out = us_size + 4

EU Size (approximate)

eu_size_out = us_size + 30

Variables

VariableDescriptionDefault
chest_inchesChest Measurement(in)38
us_sizeDerived value= round((chest_inches - 28) / 2) * 2calculated

How It Works

How Clothing Sizes Relate to Measurements

Clothing sizes vary by brand, but approximate conversions exist between US, UK, and EU systems.

Approximate Conversions

US Size ~ (Chest - 28) / 2 (rounded to even)

UK Size ~ US Size + 4

EU Size ~ US Size + 30

Always check the specific brand size chart for accuracy.

Worked Example

Chest measurement of 38 inches.

chest_inches = 38
  1. 01US size = round((38 - 28) / 2) x 2 = 10
  2. 02UK size = 10 + 4 = 14
  3. 03EU size = 10 + 30 = 40

Ready to run the numbers?

Open Clothing Size Calculator