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The UK Tax Year 2018/19: All The Key Dates You Need To Know And Plan For

A lot happens during a typical UK tax year. And more often than not, the big dates have a habit of creeping up on you without warning. That’s why it’s crucial to have a list of all the most important tax deadlines on hand. Being prepared doesn’t just save you from falling into last-minute panics as you scramble to complete all the necessary paperwork for the tax you owe – it also saves you a considerable amount of money in the long run.

To help you stay ahead of the curve, there are comprehensive tax guides to help you plan for the 2018/19 UK tax year and answer all your tax FAQs.

Use this as your go-to guide whenever you need to check the upcoming key tax dates in the United Kingdom. It could prove invaluable to the wellbeing of your business.

Key dates for the UK tax year:

  • 5th April 2018 – Last day of the 2017/18 tax year.
  • 6th April 2018 – First day of 2018/19 tax year.
  • 31st July 2018 – Second Payment on Account for the 2017/18 tax year.
  • 5th October 2018 – Deadline for Self Assessment registration for the self-employed and freelancers, or additional income earners.
  • 31st October 2018 – Paper tax return submission.
  • 30th December 2018 – Online tax return submission.
  • 31st January 2019 – Self Assessment online tax return deadline for 2017/18 and first Payment on Account for the 2018/19 tax year.
  • 6th April 2019 – 2018/19 tax year ends.
  • 31st January 2020 – Self Assessment online tax return deadline for 2018/19.



April key dates

5th April 2018 – Last day of the 2017/18 UK tax year

Thursday 5th April is the final day of the 2017/18 UK tax year – and the date by which you need to have all your documents issued to employees, statements, receipts and accounts in order. With a bit of luck, you’ll have done the vast majority of sorting for your Self Assessment submission back in January, (this is just one of the selfassessed key tax dates) so you should only have a few months of income and expenditure to organise.

Getting your PAYE tax codes (for all employees requiring income tax) and accounts in order at this time of year will serve you well moving forwards, making any tax rebate and return easier, and ultimately ensuring the taxman can get a full view of your yearly accounts if you’re ever subjected to an audit.

This date can also signify new changes for the year ahead – if you are a limited company registered in England – with the Government enforcing any new regulations they’ve floated over the past few months. These law modifications can be minor or major, so be sure to stay on top of the latest tax news and amend your processes accordingly so you don’t get stung by the next tax year date.


6th April 2018 – First day of the 2018/19 UK tax year

The first day of the new UK tax year 2018/19 is when any of the aforementioned changes come into effect, but it can also function as the perfect starting point for better income tax and national insurance practices.

Use the 6th April, and new tax year, as an opportunity to take better care of your accounts and implement processes that make recording your income and expenditure significantly easier. Make the shift from paper returns over to digital records as best as possible to start calculating tax as you go, and have organised trays at the ready for any physical receipts you need to keep hold of when the deadline for submitting expense claims comes around.

This is also a good point at which to change over to tax software if you haven’t already – which will make submitting your future online return much easier (plus, it readies you for the Government’s Making Tax Digital initiative, which is being rolled out from April 2019 onwards). When you’re always up to date, there’ll be less room for surprises later down the line.



July key tax dates

31st July 2018 – Second Payment on Account for the 2017/18 UK tax year

Alongside your online selfassessment tax returns, you’ll also be required to make two separate payments for HMRC to collect in January and July. These are known as Payments on Account, and essentially serve as advanced payments to cover you for the upcoming tax year.

Each of the Payments on Account are 50% of your previous tax bill. So, for example, if you paid £4,000 in tax, you’d make one Payment on Account of £2,000 in January, and another in summer.

The deadline for your second Payment on Account is July 31st 2018. Remember: this is for the 2017/18 UK tax year, based on the tax liability for 2016/17.



October key tax dates

5th October 2018 – Deadline for Self Assessment registration for the self employed and freelancers, or additional income earners

If you have recently become self employed or have received additional income/personal allowance in the last tax year (2017/18) but have yet to make HMRC aware of your change in employment status or income, you must notify them and register for Self Assessment by Friday 5th October – so they can accurately calculate the next amount of tax you owe.

Missing this deadline for submitting your Self Assessment will incur penalties. These can be up to 30% of the amount of tax that you owe, so it pays to be prepared.

Register online on the GOV.UK website to receive your 10-digit Unique Taxpayer Reference (keep this safe, you’ll need it when you submit your tax returns). The process can take up to 10 working days to complete – you’ll receive a letter with a code that is required for activation.


31st October 2018 – Paper tax return submission

If you have income from PAYE and a tax bill of less than £3,000 and want this to be collected by wage deductions over 12 months from April 2019, you must submit your paper tax return by 31st October 2018. This is subject to you having enough earnings to deduct the tax due.

If you prefer to do this online, you have slightly longer to submit your tax return.



December key tax dates

30th December 2018 – Online tax return submission

GOV.UK’s online service is not only useful for completing and submitting your tax return, you can also use it to check your details, look at your previous returns and print out a hard copy of your tax calculation. This will also provide insight to all activities relating to, capital gains tax, income tax, corporate taxes and tax refunds.

Check out the GOV.UK website for more information about paying your Self Assessment tax bill through your tax code.



January key tax dates

31st January 2019 – Self Assessment online tax return deadline and first Payment on Account for the 2018/19 UK tax year

This is the biggest date of the whole year for many self employed people and small business owners. If you’re earning any income outside of PAYE tax, you’ll need to submit what is known as a Self Assessment tax return, which is the document that tells HMRC what you earned, what you need to pay in tax, and the amount of money you need to pay back.

Self Assessment submissions for the self employed are due by midnight on 31st January. Miss it, and you could end up being forced to pay a considerable penalty for HMRC to collect. You’ll also need to submit your first Payment on Account for the 2018/19 tax year on this date, with the second to follow six months down the line. If you owe any money for the previous tax year, the balancing payment will also be due on this date.

There are several ways to complete and submit your Self Assessment tax return. The first, and historically the most popular, is filling your document out by hand and sending it through the post. This submission method is slowly being phased out as people turn towards tax software instead.

You can also hire the services of an accountant to complete your online return for you, and they will correspond with HMRC on your behalf if there are any issues or discrepancies.



April key tax dates

6th April 2019 – 2018/19 UK tax year ends

And then we come full circle. The 2018/19 tax year draws to a close, and you’re ready to do it all over again!

Keeping a close eye on all the key tax year start dates is extremely important when you’re self-employed. Successful business owners have more money to invest in their companies because they meet all their tax obligations and keep their accounts organised. When you know which dates you need to be prepared for, you’ll have more time to spend focusing on your company rather than worrying about HMRC.

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