Basic question.

Tax comes off gross salary, but do NI and pension come off before tax is calculated? I suspect pension comes off pretax but not sure about NI?

Check on your P60 as this gives more info.

See

http://listentotaxman.com/index.php

can work it all out

Will try and dig one out, but are you sure it tells you the order in which deductions are made?

Both Tax & Ni are taken from the same Gross Pay figure

Second what Crispy said.

ok thanks, so NI (like pension contributions) is tax free then.

so NI (like pension contributions) is tax free then.

'err No.

If your Gross weekly Pay was say £200 then the deductions would be as follows

Gross Pay £200 less Tax say £50
Gross Pay £200 less NI say £30

Gross Pay £200 less £80 = Net Take home Pay £120

If you're in a company pension scheme your pension contribution will normally be deducted from your gross salary, and you'll then be taxed on whatever is left. Your NI contribution is still calculated based on your original gross salary though.

You can see this on the calculator gusamc posted a link to. If you whack in your salary and put 0 for pension contributions and compare the answer with the figures you get with pension contributions you'll see the NI deduction is the same in both cases but the tax is less.

That's unless you're in a salary sacrifice scheme, but you'd probably know how it worked if you were. With those your employer pays the pension contribution on your behalf and then reduces your gross salary by the equivalent amount, NI and tax are then calculated based on the reduced salary, so you end up paying less NI.
Employers like this because they also make a contribution for NI and this means they are paying less as well.