Stampulator - the Stamp Calculator

About stampulator

This page calculates how many 1st/2nd class stamps you need for large letters and parcels.

Read my blog about why I created this here. When Royal Mail prices change please prompt me (comment on my blog or messge me via Mastodon( and I'll update the calculations. thanks!

I was asked for a version that shows the stamps used to be below the target value. You can find that at

Royal Mail Online Pricing is sometimes different

If you're sending parcels, you might want to check Royal Mail online (also known as Click and Drop) pricing. They sometimes have discounts or offer free collections. currently links to both price lists. Example at the time of writing, the online price for a 10KG parcel is currently £7.19 and the stamp/over the counter price is £8.39

Printable page

I designed this page to be printable. It makes for a very long poster, useful for quick reference.

Which stamps do you have?

By default, it's assumed you have the standard UK 1st (£1.35p), 2nd (85p), Large 1st (£2.10p) and Large 2nd (£1.55p) which are are the April 2024 2024 prices from Royal Mail (link also includes size and weight limits). Alternatively, enter the values of the stamps you have here and press submit. If you don't need all 4 values use a high number like 9999 so it won't be suggested in the calculation. If you'd like a page for a different country or values comment on my blog and I'll see what I can do.


Known limitations: Can only use up to 9 of each type of stamp (thus 36 stamps in total)

Your target values 135

UK Standard Services

Size Weight (up to) First Class Second Class
Letter 100g 135 85
Large Letter 100g 210 155
250g 290 210
500g 350 250
750g 350 270
Small Parcel 2kg 459 369
Medium Parcel 2kg 669 589
10kg 839 739
20kg 1249 1099

UK Signed for

Size Weight (up to) First Class Second Class
Letter 100g 305 255
Large Letter 100g 380 325
250g 460 380
500g 520 420
750g 520 420
Small Parcel 2kg 599 509
Medium Parcel 2kg 809 729
10kg 979 879
20kg 1389 1239