Royal Mail size guide
The maximum size and weight for every Royal Mail format — letter, large letter, small and medium parcel — and the weight limit for each service, for UK and international post.
Letter
100g
24 × 16.5 × 0.5cm max
Large Letter
750g
35.3 × 25 × 2.5cm max
Small Parcel
2kg
45 × 35 × 16cm max
Medium Parcel
20kg
61 × 46 × 46cm max
Measure the item in its packaging and weigh it, then check which Royal Mail format it falls into.
| Format | Length | Width | Depth | Maximum weight | Typical items |
|---|---|---|---|---|---|
| Letter | 24cm | 16.5cm | 0.5cm | 100g | Cards, letters, bills |
| Large Letter | 35.3cm | 25cm | 2.5cm | 750g1kg with Tracked 24/48 online | A4 documents, certificates, magazines |
| Small Parcel | 45cm | 35cm | 16cm | 2kg | Phones, shoes, small gifts |
| Medium Parcel | 61cm | 46cm | 46cm | 20kg | Bigger boxes, bulky or heavy items |
| Tube or roll | 90cm | Length + twice the diameter up to 104cm | — | Posters, prints, plans | |
| Parcelforce parcel | 1.5m | Length + girth up to 3m | 30kg | Anything too big or heavy for a medium parcel | |
| Parcelforce large parcel | 2.5m | Length + girth up to 4m | 30kg | Long or bulky items, express48large only | |
Every dimension is a maximum: an item over any one limit moves up to the next format. Girth is the distance around the parcel at its widest point (twice the width plus twice the depth).
The heaviest item each Royal Mail service takes in each format. A dash means the service is not offered in that format.
| Service | Letter | Large Letter | Small Parcel | Medium Parcel |
|---|---|---|---|---|
| 1st Class | 100g | 750g | 2kg | 20kg |
| 2nd Class | 100g | 750g | 2kg | 20kg |
| Signed For 1st Class | 100g | 750g | 2kg | 20kg |
| Signed For 2nd Class | 100g | 750g | 2kg | 20kg |
| Tracked 24 | — | 1kg | 2kg | 20kg |
| Tracked 24 with Signature | — | 1kg | 2kg | 20kg |
| Tracked 48 | — | 1kg | 2kg | 20kg |
| Tracked 48 with Signature | — | 1kg | 2kg | 20kg |
| Special Delivery Guaranteed by 1pm | 100g | 750g | 2kg | 20kg |
| International Tracked | — | 750g | 2kg | 20kg |
Special Delivery Guaranteed by 9am has a 2kg limit. International medium parcels go by International Tracked Heavier. Parcelforce services (Parcelforce express48, Parcelforce express24, Parcelforce expressAM, Parcelforce express10, Parcelforce express48large) take parcels up to 30kg.
| Format | Maximum size | Maximum weight |
|---|---|---|
| Letter | 24 × 16.5 × 0.5cm | 100g |
| Large Letter | 35.3 × 25 × 2.5cm | 750g |
| Small Parcel | Length + width + depth up to 90cm, no side over 60cm | 2kg |
| Medium Parcel | 61 × 46 × 46cm (International Tracked only) | 20kg |
| Tube or roll | Up to 90cm long; length + twice the diameter up to 104cm | 2kg |
| Parcelforce Worldwide | Up to 1.5m long; length + girth up to 3m | 30kg |
Minimum sizes for international post: 14 × 9cm for a letter and 14.8 × 10.5cm for a parcel. CDs and DVDs in cases sent to the USA must go as parcels. Prices by destination are on the international prices list.
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Up to 35.3cm long, 25cm wide and 2.5cm thick. If it is thicker than 2.5cm, or bigger in any direction, it is a small parcel.
750g, or 1kg if you send it by Tracked 24 or Tracked 48 bought online. Heavier than that, it goes as a small parcel.
In the UK, up to 45 × 35 × 16cm and 2kg. For international post the rule is different: length, width and depth added together up to 90cm, with no side longer than 60cm, and up to 2kg.
A medium parcel: up to 61 × 46 × 46cm and 20kg. Bigger or heavier items go with Parcelforce Worldwide, which takes parcels up to 1.5m long, 3m length and girth combined, and 30kg — or 2.5m and 4m with express48large.
Tubes and rolls go as parcels. The longest side can be up to 90cm, and the length plus twice the diameter must be no more than 104cm.
Royal Mail may ask the recipient to pay a fee before it is delivered, or return it to you. Measure and weigh the item in its packaging before you buy postage — the checker on this page tells you which format it is.
Royal Mail’s international minimums are 14 × 9cm for a letter and 14.8 × 10.5cm for a parcel. For a roll, the length plus twice the diameter must be at least 17cm, with a length of at least 10cm.
Size limits as published by Royal Mail and Parcelforce Worldwide. Service weight limits follow Royal Mail’s current online prices, last checked 13 October 2026. Always check the final requirements with Royal Mail before you post.
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