Pack first
Measure after packaging, not before. Padding and boxes can change the size category.
Royal Mail and Evri guide
UK Parcel Size Checker
Enter the finished parcel dimensions and weight to check Royal Mail size bands, Evri eligibility, and current estimated UK postage.
Prices are estimates, not checkout quotes. Public Royal Mail and Evri prices were checked on 9 June 2026. Always confirm the final price and restrictions with the carrier before posting.
Check your packed parcel
Measure the item after adding its box, mailer, padding, tape, and label.
How it works
Dimensions are checked in size order
The tool sorts your three dimensions from largest to smallest before comparing them with Royal Mail's Letter, Large Letter, Small Parcel, and Medium Parcel limits.
Weight matters as well as size. A compact but heavy parcel may move into a different service or exceed a courier limit.
Royal Mail maximum formats
- Letter: 24 × 16.5 × 0.5cm, up to 100g
- Large Letter: 35.3 × 25 × 2.5cm, up to 750g, or 1kg with Tracked 24/48
- Small Parcel: 45 × 35 × 16cm, up to 2kg
- Medium Parcel: 61 × 46 × 46cm, up to 20kg
Evri is checked separately because it uses weight bands and a length-plus-girth rule.
Packing tips
Measure what you will actually send
Round up
Round dimensions and weight up rather than down when buying postage to allow for small measuring differences.
Check the courier
Confirm current maximum dimensions, weight, restricted items, compensation, and prices on the courier's own website.
Common questions
UK parcel size FAQ
Should I measure before or after packaging?
Measure after packaging. The courier handles the final parcel, so include the box or mailer, padding, tape, and any outer protection.
Does this show exact postage prices?
No. It shows current public estimates checked on 9 June 2026. Royal Mail publishes starting prices for several formats, while Evri prices can also vary by delivery option, extras, and location.
Why does weight matter?
Couriers normally apply both size and weight limits. A parcel can fit the dimensions but still be too heavy for a particular category or service.
Which courier should I use?
Compare the current price, parcel limits, delivery speed, drop-off options, tracking, compensation, and restricted-item rules for your specific order.
Official sources: Royal Mail UK services and prices, Royal Mail 2026 price guides, Evri size and weight guide, and Evri prices.