National Insurance query

morgan1994 wrote: »

Hi there,

I was just wondering if I could get some advice/ information on NI.
I earnt £14,572 in the tax year 2016-17 (gross) and I paid £912.06 NI.
I queried this with HMRC; after checking three online calculators, they all said I should have paid £781.
HMRC got back to me saying that the deductions were correct- because I was paid weekly and my pay fluctuated I pay more NI...

Is this correct?

It is correct up to a point but has been a bit over-simplified.

You get an allowance before NI is due, for weekly paid employees it was £155 for 16/17. Each week your earnings have this £155 ignored for NI and you pay 12% of your earnings above that. So if your earnings had been spread out equally over the year you would have paid about £15 weekly. This is what the calculators you used assume, that your yearly earnings are spread out evenly or at least fairly evenly.
In fact as long as your earnings are always at or over £155 for every week of the year then the NI that is due will stay the same as the calculators give; the problem arises if your earnings fluctuate to an extent that some weeks you fall below the £155 figure or perhaps you have no earnings for some weeks. You then in affect loose that part of your allowance that your earnings fall below £155 or all of that week's allowance if you have no earnings. Any extra you earn in later weeks for example some overtime still only gets the £155 allowance so that extra has 12% NI deducted.

The difference that you have does suggest that you had quite a big variation with several weeks falling below the £155 or possibly several weeks when you had no income. Perhaps you started part way into the tax year.
Only way to really check your NI is if you list each week.

Also is it possible that sometimes you were paid late eg two weeks' wages paid together as there are special rules for this.