If you receive tax credits from HM Revenue and Customs then 31st July’s a really important day. It’s deadline day for renewing your claim, and if you miss it, it could mean your payments stop or are calculated incorrectly.

Tax credits are either Child Tax Credits – paid to working and non-working parents – and Working Tax Credits – paid to anyone eligible with or without children. Both are means tested. The amount of credit you can claim depends on your income (and household income), the number of kids you have, how many hours you work and if you’ve got a disability.  Clearly the more you earn, the less you’ll be paid in tax credits but they can still be worth thousands of pounds every year.

And not renewing properly could mean you no longer get those extra pounds. Every eligible household will get a renewal form – in a plain brown envelope – between April and July telling them what their new award will be. In many cases, you won’t need to do anything if your circumstances haven’t changed. But if they have, tell the Inland Revenue as quickly as you can so they can calculate your new claim.

You must inform the tax office if you get married or move in with a partner, reduce your working hours or your childcare costs go down, stop or you use childcare vouchers. And if you leave the UK for more than 8-weeks in a year, you must also let the revenue know. Failure to do any of these could result in you being fined £300. Most of these circumstances will lead to a reduction in your payments but you’re legally obliged to tell the tax office within 1-month of it happening regardless of whether you’ve had a renewal form.

At renewal time, you should call the helpline if you change your job or your income goes up or down, if you’ve had any other children since your last claim, your childcare costs increase or you change address.  Check any details held about you are correct too. And call them if they’re not. Keep notes of any conversations with the tax office. It’s not unheard of for there to be no record of your conversation when you subsequently contact them.

So, if you’ve had your form, make sure you check it straightaway, even if it says you’re not entitled to credits anymore. It may be that there’s a change in circumstances you need to let them know about. Claims are based on last year’s details so make sure they’ve got them right. Overpayments can come back to haunt you if the tax office finds out there’s been a mistake made, and you will have to pay them back unless it’s not your fault.

Renewing a claim’s easy – there’ll be a form in with the letter with thorough guidance notes. Read it all carefully and fill everything in properly. You must declare all your income, including any partners, and mark an X next to any mistakes. And remember to sign the form. Not doing so will cause a delay in your form being processed. If you’re unsure about any aspect of the form, call the helpline or watch one of the video tutorials on the direct.gov website.

Deadline day’s only a few weeks away. Take action now so you don’t miss out on what’s yours.