Going to work with basic salary + commission, how will tax credits be worked out?

[newstart2010]

I will have a job with a basic + commission, my wages could possibly be doubled with my commission so just wondering how working tax credits and child tax credits will be worked out???

I'm so excited to be going back to work but now have a lot of sorting to do...

Bump

Over estimate it rather than under or you will get a big shock if you are overpaid.

I returned 4 days rather than 5 after having my dd so I estimated my commision as 4/5's of what I had earnt the previous year, it was less as working less hours/less opportunity etc.

You could also ring to change your estimated annual salary if you have a few really good months?? Does your salary vary wildly from year to year for you to work out a guestimate??