Starting a self employed business alongside paye employment

[WhyNotMe40]

I'm thinking of starting a little business alongside my very part-time PAYE employee work.
What do I need to know? Do I need to get permission from work? When I inform HMRC will my tax code change? I'm assuming I will have to do a tax return...
Any advice from anyone gratefully received!

Thanks

I do this. Your employer might have something in their contract regarding this, particularly around conflict of interest or working hours so best to check.

I registered as a sole trader with HMRC and do a self assessment every year. My tax code hasn't changed but I put both earnings and PAYE tax paid into the self assessment and the tax is calculated on my SE earnings. I save about a quarter of my SE earnings every month and usually have enough to cover my tax bill.

I could use an accountant and probably pay less tax than I do (not illegally/immorally - I probably dont claim for as much as I can) but for me I feel that the cost of the accountant would negate any savings.

Im not an expert, but found HMRC very helpful so far. They even did a free one day workshop locally that I attended that covers the basics, it was very useful.

I cocked up my return in the first year, and when I went through it with HMRC we realised where I had made the mistake. I paid what was owing (about £100) and that was that.

That's really helpful thanks.
Would you register with HMRC first , or find some potential work first? I'm aiming to start getting self employed work when my youngest goes to preschool in September and I get the 30 free hours childcare, I'm hoping to get organised at least by then!

It doesn't really make much difference when you register. You're supposed to register by a certain point, but as long as you declare income and keep up with tax returns, it doesn't matter whether you do it now or later in the year. Doing it too early may increase your NI payments, I'm not 100%, NI is one thing I don't really understand.

When you do your tax return it asks you what sources of income you have, so you just tick the employed and self employed boxes and it shows you the questions for each section.

If you start as SE this tax year, you won't have to do your first tax return until after the end of the tax year, so somewhere between 6 April 2020 and end Jan 2021, but I recommend not leaving it until the last minute, because you have to register and they have to send you stuff through the post and it takes time to sort out.

I was doing the part time work PAYE and then went SE so it was already lined up and i just continued with it. I stopped PAYE 31st dec and went SE on 1st jan. I did the self assessment for the first time after the following april so my first self assessment was only for three months SE work, altho IIRC i had to include the full years PAYE.

Once your registered you have to do the self assessment at year end whether youve worked or not, so probably easier to start work then do then register. I think theres a box that asks when you started and its not a problem to back date it.

I dont think I pay extra NI as I pay it through PAYE and my SE work earnd below the threshold for extra.

I pay my NI through my job where I am an employee, nothing through self-employment.
I’m sure other posters will give you more details but I know there is a new rule that if you earn under £1000 a year as extra cash, the rules about it are quite casual - I am not sure if you have to even declare it?