UK parcel size checker
What postage size is this?
Enter the packed measurements and weight. Get the smallest Royal Mail format it fits in, in seconds.
01
Use the packed size
Measure after bubble wrap, cardboard and tape are on.
02
Rotate the box
ParcelFit checks every orientation before moving you up a band.
03
Check the service
This is a format check, not a postage price or acceptance guarantee.
What this does — and does not — tell you
ParcelFit compares your packed measurements with Royal Mail’s published format limits. Services, prices, rigidity rules and marketplace labels can differ. Confirm the current carrier or platform instructions before buying postage.
See Royal Mail’s current size guide ↗