Income Levels vs. Tax Credits

I am trying to find a table which gives an indication (not necessarily hard facts) as to how much income relates to how much tax credits, e.g. under £10k roughly equates to £x in tax credits, £10-£15k roughly equates to £x in tax credits. I am very fortunate in that my new job is a significant pay rise, but I don't know if I'm just within or without the top of the tax credits criteria.