# Royal Mail Large Letter vs Small Parcel

> The thickness cap on Large Letter is 25 mm. Miss it and Royal Mail consumer postage steps up to Small Parcel.

Live HTML: https://plaintools.io/guides/royal-mail-large-letter-vs-small-parcel

Updated: 2026-09-07

## The two bands UK sellers actually hit

Royal Mail’s consumer products still sell on named size bands, not on dimensional weight. For clothes, prints, and small crafts the decision is almost always Large Letter versus Small Parcel. The prices are different products; this page is about the physical test, not today’s 1st Class tariff.

Large Letter: maximum 35.3 × 25 × 2.5 cm and 750 g. It is meant to go through a UK letterbox (the 25 mm slot is the point). Small Parcel: maximum 45 × 35 × 16 cm and 2 kg. Once you need a box, you are usually here.

| Band | Max L × W × H | Max weight | Typical pack |
| --- | --- | --- | --- |
| Letter | 24 × 16.5 × 0.5 cm | 100 g | Unfolded cards, a few sheets |
| Large Letter | 35.3 × 25 × 2.5 cm | 750 g | A4 book in a slim mailer |
| Small Parcel | 45 × 35 × 16 cm | 2 kg | Shoes, a folded hoodie in a box |
| Medium Parcel | 61 × 46 × 46 cm | 20 kg | Bulky domestic parcels |

## Why 2.5 cm is the expensive millimetre

Sorting offices use gauges and 3-D scanners. A poly mailer that looks A4 but puffs to 28 mm because of a folded hoodie is a Small Parcel, even if it is under 750 g. The surcharge lands on the recipient as underpaid postage, or the item comes back.

Sellers who list on Etsy or Vinted feel this on sub-£15 items: the step from Large Letter to Small Parcel can cost more than the marketplace fee. Measure the packed item, not the garment on the table.

## How to measure

Length is the longest outer side, width the next, thickness the shortest, including tape and bulge. Weigh on a scale, not a guess. Tubes are different: Small Parcel max length 45 cm and length + 2×diameter ≤ 104 cm.

Use the UK parcel size checker with the packed dimensions. It classifies the band in the tab and does not quote a live price. After you know the band, price it on Click & Drop or your own labels.

## FAQs

### Is Large Letter cheaper than Small Parcel?

Usually yes on consumer 1st/2nd Class and Tracked, because they are different products. Check the current tariff; this guide does not store prices.

### Do couriers use these bands?

Evri, DHL, UPS, and FedEx generally use weight and sometimes dimensional weight, not Royal Mail’s Letter/Large Letter names. Use the dimensional weight calculator for those.

## Related tools

- [UK parcel size checker](https://plaintools.io/shipping/uk-parcel-size-checker.md) — HTML: https://plaintools.io/shipping/uk-parcel-size-checker
- [Etsy fee calculator](https://plaintools.io/shipping/etsy-fee-calculator.md) — HTML: https://plaintools.io/shipping/etsy-fee-calculator
- [Vinted fee calculator](https://plaintools.io/shipping/vinted-fee-calculator.md) — HTML: https://plaintools.io/shipping/vinted-fee-calculator

## Related guides

- [Etsy vs Vinted fees for UK sellers](https://plaintools.io/guides/etsy-vs-vinted-fees.md) — HTML: https://plaintools.io/guides/etsy-vs-vinted-fees
- [Dimensional weight divisors by carrier](https://plaintools.io/guides/dimensional-weight-divisors.md) — HTML: https://plaintools.io/guides/dimensional-weight-divisors