Girth Calculator
Choose a method below, enter your measurements, and click calculate.
What Is Girth?
Girth usually means the distance around something at its widest point. In math terms, this is often a circumference measurement for round objects. In shipping, girth has a specific definition: the distance around the thickest part of a package, not including its length.
The Basic Girth Formulas
1) For Boxes and Parcels
Shipping carriers generally define package girth as:
Girth = 2 × (Width + Height)
If a carrier also asks for “length plus girth,” then use:
Total Size = Length + 2 × (Width + Height)
2) For Round Objects
For a circle or cylinder, girth is the same as circumference:
Girth = π × Diameter
If you only know radius, first convert it:
Diameter = 2 × Radius, then apply circumference.
How to Calculate Girth for Shipping (Step by Step)
- Measure the length of the package (longest side).
- Measure the width and height (the other two sides).
- Compute girth: 2 × (width + height).
- If needed, compute length + girth and compare with your carrier limit.
Example: A box is 30 in long, 12 in wide, and 8 in high.
Girth = 2 × (12 + 8) = 2 × 20 = 40 in
Length + girth = 30 + 40 = 70 in
How to Measure Girth Directly
You can also wrap a flexible measuring tape around the object at its widest point. Keep the tape snug but not stretched. This is useful for irregular shapes where formulas are less accurate.
Common Mistakes to Avoid
- Mixing units (inches with centimeters in the same calculation).
- Using length in the girth formula for boxes (length is separate).
- Measuring at a narrow point instead of the widest point.
- Rounding too early; round only at the final step.
Quick Reference
Box
Girth = 2 × (W + H)
Circle / Cylinder
Girth = π × D
If Radius Is Known
Girth = 2 × π × R
Final Tip
If your measurement is for shipping, always check your carrier’s current size rules. Different companies (and service levels) can use different length-plus-girth limits.