How to calculate the compound interest for £100 ,for 10 years,5% interst and each year add £50 to the £100.?

How to calculate compound interst for £100 ,for 10 years,5% interst per year and each year i would like to add £50 to the capitali am looking for the formula.
Answer
Check out the link i provided, it explains how to calculate compound interest and also provides several links for compound interest calculators.