Stampulator - the Stamp Calculator 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 (email via my blog or twitter message to @srooteu) and I'll update the calculations. thanks!

Which stamps do you have?

By default, it's assumed you have the standard UK 1st (85p), 2nd (66p), Large 1st (£1.29p) and Large 2nd (96p) which are are the January 2021 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 129

UK Standard Services

Size Weight First Class Second Class
Letter 100g 85 66
Large Letter 100g 129 96
250g 183 153
500g 239 199
750g 330 270
Small Parcel 1kg 385 320
2kg 557 320
Medium Parcel 1kg 600 530
2kg 902 530
5kg 1585 899
10kg 2190 2025
20kg 3340 2855

UK Signed for

Size Weight (up to and including) First Class Second Class
Letter 100g 225 206
Large Letter 100g 269 236
250g 323 293
500g 379 339
750g 470 410
Small Parcel 1kg 485 420
2kg 657 420
Medium Parcel 1kg 700 630
2kg 1002 630
5kg 1685 999
10kg 2290 2125
20kg 3440 2955