Do I send my package as a small parcel or large letter?

Reading Time: 2 minutes

small parcel or large letter


With most couriers, the amount you pay to send your items is determined by size, weight, speed and location. For a start-up business with a conventional shaped item, shipping domestically and seeking to control outbound packaging costs, we have a few short tips that can make the information about postal options more digestible, whilst managing postal expenses. The Royal Mail have categorised UK postal sizes into 4 main sizes; letter, large letter, small parcel and medium parcel.

Internal Measurements

Good packaging distributors will detail the internal measurements to help customers identify the right option for them, highlighting the available space within the box. As simple as this may sound, using these dimensions to understand what class to categorise your parcel in is an ideal primary point. Let’s take a standard single wall 0201 cardboard box for instance, with internal measurements of 102 x 102 x 102mm. Adding an extra 2mm onto the inside measurements for tolerance purposes, and an additional 3mm across each edge due to the thickness of the board (110 x 110 x 110mm), the package would be classified as a small parcel according to the Royal Mail. This is because these measurements fall within the small parcel dimensions of 450mm x 350mm x 160mm.

Should the box type you are after not be categorised clearly, keeping a tape measure handy and using the parcel measurements generators will give you the exact dimensions and reveal what category your parcel is in. This will ensure you’re making best use out of the postal services and ease the worry of getting overcharged.

After the Royal Mail changed the rules surrounding what is considered a small parcel, if your package can fit through a letter or post box with little assistance, this can still be classified within the large letter category. Back in 2013, this would mean you would have had to pay more for sending the same package, as a small parcel.

This rule change gives consumers more flexibility and offers businesses huge savings of £420*, for a 1st class service of a product weighing between 101g and 250g being posted within the UK.

Changing Class

Should you decide you want to reduce your postal cost with a larger item, try switching from medium parcel to small parcel, with boxes specifically designed to fit into the small parcel category. Undertaking this change in your business could potentially save £220* a year.

Similarly should changing the category size of your parcel not be viable, consider utilising a different speed type. Switching from 1st class to 2nd class signed for, stretches the speed of delivery to 3-5 working days in exchange for the assurance the product will be signed for upon delivery. While this option may not directly switch the postal category size, switching the class assures the sender accountability, and offers a saving of £140*.

These savings may not seem like much, however for businesses just starting out it can make a huge difference, plus… it all adds up year on year!


Use BLOGFREEBIE** when placing your order across our postal packaging range and receive a package of free sweets from us.

*per 200 orders

**T&C’s apply

The following two tabs change content below.

Rick Stanford

Rick has been a salesman in the packaging supplies business for more than thirty years. Now semi-retired, he divides his time between tending his allotment in north Devon, getting depressed at the continuing travails of his home-town football club Macclesfield Town, and sharing his considerable experience and knowledge with the readers of the Davpack blog. Davpack

Latest posts by Rick Stanford (see all)

2 Comments to Do I send my package as a small parcel or large letter?

  1. Archer says:

    Could I send a small object such as keychain that is within 2.5mm thickness in a large letter?

    • Ellie says:

      Hi Archer,

      Depending on the length/height of your keychain you would probably be able to send it as a standard letter through the Royal Mail.

      For it to be sent as a letter the size/weight must not exceed: Length: 240mm, Width: 165mm, Thickness up to and including: 5mm, Weight limit: 100g

Leave a Reply

Your email address will not be published. Required fields are marked *