First time self-assessment... help!

may91

Hi, sorry if this seems like a silly question but this is my first time doing a self-assessment and my head is swimming!

Basically, I earnt a small amount from my previous job just after the new financial year (I left the job to go freelance on the 13th April 2018). On my P45 document, this small amount is the only number listed in 'total pay' and has been taxed as PAYE.

On my first pass of the self-assessment form, I left the following two boxes empty:

Pay from [employer] - total from your P45 or P60. Enter the amount before tax taken off: (Optional)

and

UK tax taken off BBC pay: (Optional)

This was as I wasn't sure if it meant my ENTIRE pay I'd been at the company (6 years), or just this financial year. Also, as it said 'optional' I wondered if it was important - maybe they already have this info so don't need it?
I finished the form and calculated my tax - all fine. Then I went back to this section, and on second thoughts I assumed that it means total pay from this financial year, and entered the small amount, and the tax that had been taken off into the relevant boxes. When I then went back, the next calculation of tax was a LOT higher.
I'm so confused by this, as the small amount (under £1500) hasn't affected my tax bracket, and was already taxed as PAYE. Why would I then have to pay tax AGAIN on this? Am I missing something really obvious?

Any help would be massively appreciated!

TheCyclingProgrammer

You need to post the calculations. You are supposed to include all of your income for the tax year including earnings from your P45.

may91

OK thank you. Do you have any ideas as to why it might add up to so much more on my tax bill when the tax for this particular payment has already been payed as PAYE?

BoGoF

Without seeing the figures it's impossible to say.

How much is a 'lot' higher with the PAYE income?

may91

It's the difference of about £300. It might not sound huge but my total earnings were only around £23,000 so it does make a big difference.

BoGoF

Even though you paid tax on the PAYE income you still used some of your tax free personal allowance against it. When you didn't include it you would have been getting the full tax free allowance of £11,850 against your freelance income.

may91

Ah! That makes complete sense. I knew there would be something simple I was missing. Thanks so much!

BoGoF

I would say an increase of £300 seems high for an income of 'under' £1500. Are you sure you put the PAYE tax deducted in the box? What were the P45 figures.

A £300 difference would be about correct for £1500 income that had no tax deducted.

may91

Ok so I've just been on the phone to HMRC after a long stint of being 'on-hold'... and apparently it seems that I was undercharged tax temporarily (on the incorrect tax code) and owe more. I still can't say I understand the situation 100%, but it seems a bit clearer now.

TheCyclingProgrammer

I will repeat - nobody can really help you understand what is happening unless you are willing to post the full calculation. Otherwise it’s all just guesswork.

may91

Of course. And guesswork has worked fine and pointed me in the right direction. So thanks, again.