How to calculate employer's and employee's NI

[palatino winotype]

I'm weasonably confident to not be IR35 caught. I also have PCG plus membership and have had my contract vested by QDOS.

That said, I am going to hold some money back for the worst case scenario.

Is there some kind of ready weckoner or formula to use to calculate what NI would be due over the 18 months I've been on this project?

Would it be unreasonable for my accountant (NW) to do this for me?

[northernladuk]

Would it be unreasonable for my accountant (NW) to do this for me?

Well you pay them so I am sure it isn't too much to expect. NW are very helpful to people who are not their customers on the board so I am absolutely certain he would do it for you.

[Craig@Clarity]

It wouldn't be unreasonable and they will be able to help you out here.

Anyway, in advance, it's a simply calculation assuming you're a "standard" employee. Class 1 NIC is 12% on earnings between £146 - £770 per week (£634 - £3,337 per month or £7,605 - £40,040 per year) and then 2% thereafter.

Employer's NIC is 13.8% on earnings over £144 per week (£624 per month or £7,488 per year)

Here's a handy linky HM Revenue & Customs: Rates and thresholds for employers

[palatino winotype]

It wouldn't be unreasonable and they will be able to help you out here.

Anyway, in advance, it's a simply calculation assuming you're a "standard" employee. Class 1 NIC is 12% on earnings between £146 - £770 per week (£634 - £3,337 per month or £7,605 - £40,040 per year) and then 2% thereafter.

Employer's NIC is 13.8% on earnings over £144 per week (£624 per month or £7,488 per year)

Here's a handy linky HM Revenue & Customs: Rates and thresholds for employers

Thankyou Craig.

Another issue is expenses - under IT35 you can only claim 5%. Does thus mean that potentially some of what I have claimed will be disallowed and subject to NICs? I'm guessing this doesn't include travel and accommodation but I've claimed for books, computer equipment etc over the past couple of years.

[Craig@Clarity]

The 5% under IR35 is to cover expenses not allowable under the deemed salary calculation. If the total expenses come out to more than the 5% you create a loss.

Assuming travel and accommodation is allowable under the 24 month rule, these will count as allowable for IR35 i.e. isn't part of the 5%.