So I'm trying to work out how much I would earn if I took a certain job. I have used the tax credit calculator and it asks what my income was for April 2016 - 2017 and then gives me a large amount of tax credits (I earned a low salary last tax year). But the new job would be full time and between 30-35 k and if I input that as my last years earning I would get no tax credits or very little.
So how does it work? Should I be inputting last years tax credits or this years to get a better idea of how much I would get? 