Tax Credits - what to declare

[Cariad]

Can anyone help me please? When I give my income to claim for Child Tax Credits, do I give them my gross income or my income once I have deducted expenses?
I'm a bit confused and I'm not sure I've given them the right information.

[maisiemog]

I was told to give my profit so that is what you make after all your deductions.

[Cariad]

Thanks, didn't want to do that and then end up with a bill for overpayment of tax credits!