How to complete a self-assessment tax return
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- If you're self-employed, a sole trader or a company
director you pay your tax using a self-assessment tax
- You need to complete your tax return by 31st
- (Limited companies pay corporation tax through a corporation
tax return, and deadlines are different. If you need to work out
the tax for your limited company, find out what you need to in our
guide on how to calculate
the tax for a limited company.)
- You'll automatically get sent a self-assessment tax return
after you've registered as self-employed.
- You can use accounting software to complete your tax return.
Make sure it's approved by HMRC by checking this
- It can be well worth getting an accountant on board to help
with this, or at least to check what you've done yourself. Read our
guide on how to find an
What you need to fill out
- If your business' annual turnover was less than
£70,000, you fill out the 'short' form, which is only a few
- If turnover was more than £70,000, you need to
complete the longer and more detailed 'full' form.
- If you're unsure which return you should be filling out, call
the HMRC self-assessment helpline on 0845 900 0444.
- You can complete a paper tax return and post it to
HMRC, or do it online.
- If you do it online, you have to complete the full form, but
the deadline is three months later.
- You may also need to fill out additional pages,
for things such as pension contributions or income from renting
land or property. The booklet called 'How to fill in your Tax
Return' that HMRC sends you along with your paper return (which you
will get whether or not you want to complete your return on paper
or online) will explain which additional forms you need and how to
obtain them. (You can also find a link to this booklet below in the
- For the short form, you then need to provide
details of any employment you've had in the last tax year, details
of self-employment and your business' financial records, *allowable
business expenses*, net profit or loss, tax allowances for vehicles
and equipment, losses, Class 4 NICs and CIS deduction, and any
other income you have received (such as dividends, benefits,
and so on.)
- For the full form, you'll also need details of any
UK savings and investments, UK pensions, annuities and benefits,
life insurance gains and AVC refunds and any other taxable
Follow the steps below to make filling out your tax return as
painless as possible:
- Read through booklet called 'How to fill in your Tax
Return' that HMRC sends you along with your paper return
- Work out if you need to fill out any additional
pages - request them from HMRC if necessary.
- Collect your financial records for the tax year
that's just ended (starting and ending on 4th April), including
your profit and loss account, business records and business
- Get together any relevant bank statements, dividend
counterfoils, personal pension schemes and so on that you
need - use HMRC's booklet 'How to fill in your Tax Return' to
figure out what exactly you need.
- Get together any relevant forms such as P60, P45, P11D,
PAYE notices of coding that you need - use HMRC's booklet
'How to fill in your Tax Return' to figure out what exactly you
- Stick to the deadlines below to avoid getting
fined for a late return or payment.
- Make sure you've signed and dated a paper
Paying your business tax bill: how much and how
- If you fill out a paper return, HMRC
send you a letter telling you how much tax you owe.
- If you do it online it's calculated
- Your total tax bill takes account of the financial year ahead
as well as the one you've just reached the end of. So in
addition to what you owe for this tax year (your 'balancing
payment'), you have to pay the same amount again to have it on
account for the following tax year - since HMRC predicts you
will owe the same in tax from one year to the next. (You need to
notify your tax office if you expect to owe a very different amount
in the following tax year.)
- The payment on account (for the year ahead) is split equally
and paid in two instalments - the first combined with your
balancing payment for the tax year that's just finished and due by
31st January, the second by July
- When you get to the end of the next tax year, any balance owed
to you or that you owe, according to what you paid on account the
previous year, is added to or deducted from your balancing payment
for that year. In other words, if your tax bill is different from
the previous year's tax bill, you will either have to pay HMRC the
extra bit you owe on top of what you paid last year on account (if
you owe more tax than you did last year), or they will knock what
they now owe you off your current bill (if what you paid on account
the previous year was more than you actually owe).
If you owed £1,000 for the tax year 2008/09, HMRC assume that
you'll owe another £1,000 in 2009/10. That means you have to pay
£1,500 by January 31st 2010 - your balancing payment for 2008/09
plus the first instalment of your payment on account for 2009/10.
Then you pay another £500 by July 31st 2010 - the second instalment
of your payment on account for 2009/10. If, say, you then got to
the end of 2010 and realised that you actually owed £1,200 for tax
year 2009/10, you'd have to pay £200 by January 31st 2011 as your
balancing payment for 2009/10 (£1,200 less the £1,000 you'd already
paid on account).
- You can pay by debit card, by phone, cheque, post office, or online - you'll need
your taxpayer reference number.
- Paper returns: in by October 31st
- Online returns: completed by January 31st
- Penalty for late return is £100
- First instalment for tax payment: by January 31st
(which means if you fill out your online return on 30th January,
you'll have to pay on the same day)
- Second instalment for tax payment: by July
What do I do as a limited company?
You need to pay corporate tax. Find out more in this guide on how
to calculate tax for a limited company.
I'm part of a partnership - who fills out what?
Each partner needs to complete partnership pages as part of their
individual tax return, but only one partner has to complete the
partnership tax return.
What happens if I didn't make any profit or I made a
Unfortunately, if you registered as self employed, you still need
to complete a return and send it off in time. The return shows you
where to indicate whether you've made a net profit or loss.
What if I don't know the exact figures I need to put
HMRC advises you to use an estimate - a figure you want HM Revenue
& Customs (HMRC) to accept as your final figure - or a
provisional figure - one you want to use until you can confirm the
actual amount (you must tell HMRC it is a provisional figure).
But it's best to give them a call on 0845 900 0444 to check
What if I don't know whether I was paid through PAYE or
not for work I did?
Your first stop would be to get in touch with the person who paid
you for the work, but if that's not an option, call HMRC on 0845
900 0444 for advice, as there are different solutions for different
What if I don't have my P45?
As above, your first stop would be to get in touch with your
former employee, but if that's not an option, call HMRC on 0845 900
0444 for advice.
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- The 27-page booklet 'How to fill in your Tax Return', that HMRC
sends you with your paper tax return, really is invaluable. It
takes you through the different stages and boxes and helps you
figure out what you need to fill in. It also points you towards any
additional pages you need to fill out, and helps you work out
things like allowable business expenses.
- HMRC's guide to doing your self assessment tax return online.
- You can also get the notes online here:
- HMRC self assessment helpline - 0845 900 0444 (open from 8 am
to 8 pm every day, except Christmas Day, Boxing Day and New Year's