How do you calculate if its worth getting a job?

[TheDeathAndGlories]

We are at that point income wise that is on the edge of recovering tax credits of not (4children) things are very tight so we've been looking at me getting a Saturday job. My worry is that the very small of extra income I will being in will push us over the limit and our tax credits will stop. They are more than I will be earning
I've done several of the online yet things (entitled to/government) and they give different answers
Having said that neither gives our current amount with our current figures.
Anyway so I am unsure how to find out how much we would get/not get.
I'm perfectly happy to work and lose family time if its worth it but we can't afford to live on less (hence the job)
How do I work out if its worth getting a Saturday job or not?

(Sorry if garbled, I'm on my phone and can't go back)

I wrote it all down on paper. Income now with tax credits vs income with job. Then write down bills, rent/mortgage etc and see how much you have left.

The only other way is to go to the job centre and get them to do a calculator for you, they don't mind doing 2/3 different scenarios with you.

Thanks for replying
I'm surprised you can understand what it says. Stupid phone app

I might see if I can speak to the job centre on the phone then as the nearest takes more time than I have while the children to get to and back