I mostly buy RM48 large letter up to 100g and I'm trying to work out what the price will be when they change on Monday 24th March 2024.

Here's my calculation.

RM48 LL 100g - £1.12

Fuel surcharge at 8% - £0.09

Green surcharge - £0.04

Total ex VAT - £1.25

Total inc VAT - £1.50

Does that look correct? I'm not sure if VAT is applied to the surcharges.

Also, given Amazon charge a referral fee on the postage cost, the actual postage cost for my category is

Royal Mail postage fee - £1.50

Amazon fee at 15.3% = £0.23

Total postage cost = £1.73