Childcare Vouchers versus Childcare Element of Tax Credits

Weedy

Does anyone know how to get some detailed information of the formula used to calculate the childcare element of tax credits?

I'm due to go back to work after maternity leave and our joint income hovers around £40k which seems to be a threshold. I'm unclear as to whether we would be better off taking childcare vouchers from our employer (which saves us approx 29% of our childcare costs through salary sacrifice) or whether we might get a higher percentage of help through the childcare element of tax credits.

There seems to be a sliding scale upto and beyond the £40k mark which is right where we are at. I've spoken to a few people in the Tax Credit team presenting various scenarios which is helpful, but I want to understand the formula so I can work it all out myself before I go ahead and cancel childcare vouchers.

I'm grateful for any advice that anyone can offer.
Thanks
Weedy

DX2

Any good?

Childcare vouchers and tax credits - better off calculator
http://www.hmrc.gov.uk/calcs/ccin.htm

Weedy

Thank you. The calculator is helpful, but it doesn't tell me how it's calculated. I really want to understand how it's worked out and to know the formula. Any other suggestions?

Thanks.