How this calculator works
Girth = 2 × (width + height). Combined size = longest side + girth.
Using this result
Length plus girth is a size check used by many parcel services; it is separate from package weight.
Next step: Compare the result with the current limit for the exact service and destination you plan to use.
Worked example
A 36 × 14 × 12 inch parcel has a 52 inch girth and an 88 inch combined length plus girth.
How to measure
- Identify the single longest side as length.
- Measure width and height around the thickest point.
- Use outermost packed dimensions.
Common mistakes
- Using all three sides in the girth formula.
- Not assigning the longest side as length.
- Comparing against a limit from a different service.
Planning note: This result is an estimate, not a carrier quote. Equipment, services, limits and rounding rules can vary. Confirm operational decisions with the relevant provider.
Formula implementation and worked example reviewed September 9, 2026. See the methodology and sources.