Last update: 11th April 2023
Royal Mail determine if a letter is large or small depending on its size and weight but charge the same price for delivery to all UK addresses – whether its a local letter of being sent from Lands Ends to John O’Groats!
For international letters, please see our international letter guide and for envelopes see our envelope guide.
What is a Letter vs a Large Letter?
Letter / Small Letter
- Max length: 24cm
- Max width: 16.5cm
- Max thickness: 0.5cm
- Max weight: 100g
This is large enough for something A5 in size or a C5 Envelope size. Greetings cards often have printed on the reverse whether they qualify as a “small letter”. A small letter just needs either a 1st or 2nd class stamp (See our stamp guide below).
Large Letter
- Max length: 35.3cm
- Max width: 25cm
- Max thickness: 2.5cm
- Max weight: 750g
This is large enough for something A4 in size or a C4 Envelope size. If a large letter weighs less than 100g it just needs either a 1st or 2nd class large letter stamp and if it weighs more than 100g it’ll need a combination of different priced stamps – to work out the exact postage Royal Mail have a helpful price finder tool here.
If you’re sending something larger or heavier than the above, you’ll need to send a parcel instead.
Sending a Letter Cheaper than Royal Mail
Royal Mail is the largest letter delivery company in the UK, but it isn’t the only letter delivery company. Whistl is the second largest letter delivery company in the UK and delivers 4 billion items each year in the UK.
You can save up to 13% of the cost of second class stamps if you post a letter with Whistl instead – click here for more information via Parcel2Go
WHAT ARE THE DIFFERENT Royal Mail LETTER POSTAGE OPTIONS?
Royal Mail determine if a letter is large or small depending on its size and weight but charge the same price for delivery to all UK addresses
2nd class standard
- Delivery time: 2-3 working days
- Confirmation of delivery: No
- Cost*: Letter 75p; Large Letter from £1.55 for <100g
This is the cheapest service which charges from 75p per letter and delivers in 2 to 3 working days, including Saturdays.
Every 2nd Class item is covered against loss or damage up to £20 or the value of the item, whichever is lower. However compensation for valuables, such as money and jewellery is not available on this service.
1st Class Standard
- Delivery time: Aim Next Day
- Confirmation of delivery: No
- Cost*: Letter £1.25; Large Letter from £1.95 of <100g
Like 2nd Class, every 1st Class item is covered against loss or damage up to £20 or the value of the item, whichever is lower. However compensation for valuables, such as money and jewellery is not available on this service.
Signed for
- Delivery time: 1-3 working days
- Confirmation of delivery: Yes
- Cost*: £1.50+ surcharge on either 1st or 2nd class postage
Special Guaranteed
- Delivery time: Next day
- Confirmation of delivery: Yes
- Cost*: Most Expensive, prices from £7.35
or important items. Options include delivery by either 9am or 1pm the next day (including a Saturday guarantee) as well as compensation for loss of damage of either £500, £1,000 or £2,500.
* As of October 2023
Where can I buy Royal Mail Postage stamps?
You can buy online 'print-at-home' stamps or 'stick-on' stamps either online or in a wide variety of retailers
Multiple online retailers offer Royal Mail stamps at cost price as well as options for free delivery with large orders. We’ve found the best way of buying stamps online at ‘cost price’ is from Staples UK or Office Stationery
Alternatively, you can save up to 13% of the cost of second class stamps if you post a letter with Whistl instead – click here for more information via Parcel2Go
Buy Online, Print at Home
Buy in store
A wide variety of retailers stock postage stamps including Newsagents, Stationers, Supermarket tabocconist counters, Post Office branches or greeting card shops.