I don't really understand exactly how the 'call set-up fee' is applied to individual calls!
The calls listed below are from my last phone bill-calls are both National ones!

Time Duration £Cost

16:47 00:14:24 0.470

16:10 00:04:08 0.190

I am on 'option 1' at the moment.

Many thanks for your help.

Like most of the public, I don't calculate without taking VAT into consideration from the start.

Hence, with VAT, the first call (which BT rounded up to 15 minutes) cost:
15 x 3¼p per minute + 6p connection = 55p (i.e. 47p + 17½% VAT)

With VAT, the second call (which BT rounded up to 5 minutes) cost:
5 x 3¼p per minute + 6p connection = 22¼p (i.e. 19p + 17½% VAT)

I'd strongly recommend you use 18185 for such weekday daytime calls - had you done so, each would only have cost you 5p.

Many thanks Heinz-all now clear and will investigate your suggestion re using alternative number.
In the dozens of DS messages on this subject I don't think one has actually explained the costing as clear and simply as you have done-many thanks!
This latest price increase by BT has certainly generated a lot of very useful DS messages and highlighted a lot of facts-how many people for example actually realised all calls were 'front loaded' with a 'call set up fee'?
To my embarrassment-I had not realised this fact until this DS thread kicked off-LOL!!!!!

Happy to oblige gwynne.

If you want to go a stage further and review all your voice telephony costs, my "6-steps" post on MSE is regularly updated.