Tax return question (UK)

I have never known how this work for sure and since it might effect me soon I thought I would ask. It's about tax returns. It concern the UK, but I am going to assume this works the same way everywhere else too.

If you have a full or part time job that deducts taxes from you, but you also make some extra money from other work [freelance], when you go to fill out your tax return, do you need to mention the earnings from the full or part time job as well as the freelance work, or just the freelance work, since they ought to already know my job earnings, as I already have taxes deducted from the payslips?

The tax return (UK) asks you for ALL your earnings that is from a full time job, part time job, freelance or any other earnings even interest on your taxed bank accounts or savings. Then on the form you can complete the part which states how much tax you have already paid. They will work out if you owe them or they owe you tax.

Remember that UK tax year runs April to April, so for this tax year it is 6th April 2018 to 5th April 2019.

Everything, but be careful - if the freelance work is more than just something very occasional, they might question why you didn't register as self employed.

There's a good link here that explains it -
freelanceuk.com/news/4027freelancers%E2%80%99_Questions_how_pay_tax_freelance_work.shtml

Okay I didn't realise that I need to declare all earnings, including already taxed ones. Thanks for the info folks.

I don't need to do the self assessment for this year anyway, as the freelance work didn't start until after April this year.