From 6 April 2014 the annual allowance for tax relief on pension savings in a registered pension scheme was reduced to £40,000. This includes contributions made by anyone else into your pension such as your employer. If your pension savings exceed this amount you may have to pay a tax charge and give details of this on a Self Assessment tax return.
You can use this tool to work out whether you may be affected by an annual allowance charge and have to complete a tax return for tax years up to and including 2014 to 2015. If you are affected it will recommend you go on to use the pensions savings annual allowance calculator.
For 2015 to 2016 and later tax years go to annual allowance calculator.
You'll need to know the type of pension scheme you're contributing to and the amount of contributions you've made.
Use the annual allowance checking tool to work out whether you're likely to have a liability to the annual allowance tax charge for years up to and including 2014 to 2015.
If you already know you're likely to have an annual allowance liability it's best to use the pension savings annual allowance calculator instead.
A guide to tax on your private pension contributions can be found on GOV.UK.