How do I work out my taxable profits?

Updated on 12 July 2016

There are many steps to working out your taxable profits. We take you through the process.

How do I work out my taxable profits?

In order to do this, there are a series of steps to take:

  1. Prepare a set of accounts for your business. You can find guidance in the section below .
  2. Once you have your accounts, you make tax adjustments for business expenses that are not allowable and capital allowances.
  3. You then need to work out in which tax year the profits shown in those accounts are to be taxed. This depends on the basis period.

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How do I prepare accounts?

You do this from the records that you have. Your accounts should show all of the income and expenses from your business for the period of the accounts. After that you can decide whether the expenses are allowable or not.

Normally accounts are prepared on an accruals basis, but you may be able to prepare them on a cash basis.

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What is the accruals basis?

This is the usual way that accounts are prepared in the UK. In general terms this means that all income earned and all expenses incurred during the accounting period are included in the accounts, whether they are paid or not.

For example, if you invoice a customer on 31 December 2015 and draw up accounts to 31 December 2015, this invoice would be included, whether the customer had paid it or not.

Similarly, if you paid your annual insurance bill on 1 July 2015 to cover the period from 1 July 2015 to 30 June 2016, you would only include half of the cost in the accounts to 31 December 2015 even though you had paid the full amount; the other half would be included in the accounts for the following year.

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What is the cash basis?

Whereas the accruals basis looks at income earned and expenses incurred, the cash basis looks at income actually received and expenses actually paid in the accounting period.

If you meet certain criteria, you can choose to use the cash basis instead of the accruals basis.

You can read about more about this on our page 'what is the cash basis?'.

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What is my accounting date?

Normally accounts are prepared to the same date in each year (the accounting date), so you want to choose a date that is convenient for you. You can have any day in the year as your accounting date although from a tax point of view, the easiest date to choose is 5 April, but any date from 31 March to 5 April inclusive will be treated as 5 April to make things as easy for you as possible.

If you make up your accounts to 31 December each year, this is your accounting date and the 12 months to 31 December are your accounting period.

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Can I change my accounting date?

It is possible to change your accounting date for tax purposes but you will need to explain to HM Revenue & Customs (HMRC) in your tax return why the change is necessary. They may not accept your explanation in which case you will have to keep your existing date.

However if you have a reasonable argument it is likely to be accepted. For example, you have two businesses and you want the same accounting date for each. You cannot just keep changing the date each year to suit yourself.

If you want the change to be temporary – you can ignore it for tax purposes. Otherwise if you have:

  • Made up accounts to a date different from that used for your tax in the previous year; or
  • You intend to draw up a set of accounts for more than 12 months so that no accounting date falls into the current tax year; or
  • If you changed your accounting date last year but this was not accepted by HMRC and you are using the same date again

You will be treated as having changed your accounting date.

Changing your accounting date will mean that you will have a new basis period for your taxable profits. See the section below for how this is calculated.

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How long do I have to keep my business records?

In order to prepare your accounts and fill in your tax return you will need to keep records of income and expenses.

You must keep these records for at least 5 years and 10 months after the end of the year of assessment. A tax year starts on 6 April and finishes the following 5 April. So the tax year 2016/17 starts on 6 April 2016 and ends on 5 April 2017. Records for that tax year need to be kept until 31 January 2023.

If you do not keep proper records, you may be given a penalty by HMRC. You can find out more about what records you should keep and the penalties for failure to keep records in our section ‘business records checks’.

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I have prepared my accounts and decided which expenses are not allowable. What do I do next?

You take the profit per your accounts and add to it any business expenses that are not allowable for tax purposes. This is because you may incur expenses that reduce your profit in your accounts but which HMRC do not allow you to deduct for tax purposes. You must therefore add them back in so that you pay tax on them.

Example

Bernard’s accounts for the year to 31 March 2016 show a profit of £17,300. The accounts include all of his motoring expenses of £12,000, but Bernard estimates that only 60% of his costs are actually business costs.

Profits per accounts £17,300
Add: private motoring expenses £4,800 (ie 40% of £12,000)
Adjusted profits £22,100


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How do I get relief for capital allowances?

Some expenditure will be treated as capital expenditure rather than a trading expense. An item will generally be a capital expense rather than a trading expense if it is an item you need for your business and it is likely to have an enduring benefit. There are some exceptions to this (such as cars, vans and motorcycles).

If you are using the accruals basis you cannot deduct capital expenditure from your trading profits. Instead you may be able to claim a capital allowance for that expenditure.

Once calculated, capital allowances page are treated as a trading expense and are deducted from the adjusted profits as noted above. You should note that deduction of capital allowances may create a loss for tax purposes or increase a loss.

Example

Continuing the example of Bernard from above: Bernard bought a new machine in January 2016 for £2,500. That will qualify for 100% capital allowances (annual investment allowance).

Bernard's taxable profits become:

Adjusted profits (from above) £22,100
Less: capital allowances £2,500
Taxable profits £19,600


See our capital allowances page for more information on calculating capital allowances.

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I know my taxable profits, but how do I know when they will be taxed?

They will be taxed according to the relevant basis period.

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What is a basis period?

This is the period for which you will be charged tax in a particular tax year. Normally, for a continuing business this is the 12-month period of accounts that ends in that tax year.

Example

Trevor makes up accounts to 31 October each year. His basis period for 2016/17 is the year ended 31 October 2016. This means that the tax Trevor will pay for the 2016/17 tax year is the tax on his taxable profits for the basis period 1 November 2015 – 31 October 2016.

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How do I know my basis periods when I first start self-employment?

For the first tax year, your basis period is always the period from the date you started trading until the following 5 April.

Remember that if your accounting date falls from 31 March to 5 April inclusive, this will be treated as 5 April for these purposes.

Example

Gunther starts trading on 1 July 2016. His basis period for the 2016/17 tax year is the period from 1 July 2016 to 5 April 2017.

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How do I work out my basis periods after that?

For the second tax year that you are self-employed you may fall into one of three different categories:

  1. If you have prepared a set of accounts for at least 12 months that end in that second tax year, then the basis period for that tax year is the 12 months ending on the accounting date.


    Example

    George starts trading on 1 September 2015. He draws up accounts to 31 December 2016 and to the same date each year after that. The basis period for his first year (2015/16) is the period from 1 September 2015 to 5 April 2016. The basis period for his second year (2016/17 tax year) is the year from 1 January 2016 to 31 December 2016. The basis period for his third year is the year to 31 December 2017.

    You will see that to arrive at these figures George will have to split the figures for his 16 month period of accounts. This is done on a strict time basis. For example, if George’s accounts for the 16 month period to 31 December show a profit of £16,000, then it is assumed he made a profit of £1,000 each month evenly over the period, so for the basis period from 1 September 2015 to 5 April 2016, he would be assumed to have profits of £7,000 – equivalent to profits for seven months.
     

  2. You may have no accounts that actually end in the tax year: if that is the case, the basis period is from 6 April to the following 5 April.


    Example

    Alexander starts trading on 1 February 2015 and draws up accounts to 30 April 2016 and to the same date each year after that. The basis period for his first year (2014/15) is the period from 1 February 2015 to 5 April 2015. The basis period for his second year (2015/16) is the period from 6 April 2015 to 5 April 2016. The basis period for his third year is the 12 months to 30 April 2016.
     

  3. You may prepare a set of accounts that end in the tax year, but they are not at least 12 months long. In that case, the basis period is your first 12 months of trading.


    Example

    Louis starts trading on 1 January 2015 and draws up accounts to 30 June 2015 and to the same date each year after that. The basis period for his first year (2014/15) is the period from 1 January 2015 to 5 April 2015.The basis period for his second year (2015/16) is from 1 January 2015 to 31 December 2015. The basis period for his third year is the year to 30 June 2016.

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I seem to be taxed twice on some profits. Is that right?

The tax system operates so that overall all business profits are only taxed once but, as you can see from the examples above, sometimes at the start of a business profits are taxed more than once. These profits that are taxed twice are called overlap profits.

Example

Consider the Louis example above.

In year 1 (2014/15) he is taxed on the profits from 1 January 2015 to 5 April 2015.

In year 2 (2015/16) he is taxed on the profits from 1 January 2015 to 31 December 2015.

In year 3 (2016/17) he is taxed on the profits from 1 July 2015 to 30 June 2016.

You will see that in year 2 he is taxed on the profits from 1 January 2015 to 5 April 2015 that were already taxed in year 1.

In year 3 he is taxed on the profits from 1 July 2015 to 31 December 2015 that were already taxed in year 2.

If we assume that Louis’s taxable profits for the 6-month period to 30 June 2015 were £6,000 and his profits for the year to 30 June 2016 were £18,000, then his taxable profits and overlap profits would be as follows:

Tax Year Taxable profits Overlap profits
2014/15 £3,000 (3 months) nil
2015/16 £15,000 (12 months being 6 months to 30 June 2015 plus 6 months to 30 June 2016) £3,000 (3 months to 5 April 2014)
2016/17 £18,000 (12 months to 30 June 2016) £9,000 (6 months)


Total overlap profits are £12,000.

 

As you should only be taxed once on income, you can use these overlap profits at a later date to reduce the tax you pay.

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When can I use overlap profits?

You can use overlap profits either when you cease to trade or if you change your accounting date to a date closer to the end of the tax year, that is 5 April. See below for an explanation of how each of these works.

You will need to keep a note of the amount of overlap profit you have and what number of months it relates to. You carry your overlap profit forward on your tax return until you are able to use it.

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What happens to my basis period if I change my accounting date?

If you change your accounting date you will need to work out your new basis period using the following rules:

  1. If your new accounting date in 2016/17 is more than 12 months after the end of your basis period for the previous year (2015/16), your new basis period will be from the end of that basis period to your new accounting date.


    Example

    Susan has a basis period in 2015/16 that ended on 30 June 2015. She decides her new accounting date will be 30 September 2016. Her basis period for 2016/17 is the 15 months from 1 July 2015 to 30 September 2016. At this time she can use overlap relief equivalent to 3 months of profits to reduce the tax she has to pay for the tax year 2016/17. If she was carrying forward overlap profits of £4,000 that equated to 4 months profits, then she would use overlap profits of £3,000 now and still carry forward £1,000.
     

  2. If your accounting date in 2016/17 is less than 12 months after the end of your basis period for the previous year to 2015/16 your new basis period will be 12 months ending on the new accounting date.


    Example

    Tom has a basis period for 2015/16 that ended on 30 September 2015. His new accounting date is 30 June 2016. His basis period for 2016/17 will be the 12 months to 30 June 2016. He is creating a further 3 months of overlap profits that will be carried forward.

If you have changed accounting date and your basis period is more than 12 months, you can use your overlap profits to reduce the basis period to 12 months – see the example Susan above.

Further example on use of overlap profit

You have unused overlap profit of £6,000 which came about because 6 months of profits overlapped when you started your business. You then change your accounting date and your new basis period for 2016/17 is 15 months. You can only be taxed on 12 months profits.

You have 6 months overlap relief available and you need to reduce the 15-month basis period to 12 months so you use 3 months of your relief up.

Overlap relief used

3/6 x £6,000 = £3,000

Your profits for 2016/17, which are based on a 15-month basis period will be reduced by £3,000 and you still have 3 months overlap profits to carry forward.

If you wish to find more information on change of accounting date, you can look on the GOV.UK website.

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What is my basis period in my last year of trading?

This basis period starts just after the previous period ended and stops on your final day of trading.

Example

You have been trading for many years making accounts to 31 October. You cease trading on 31 August 2016. Your accounts for the year to 31 October 2015 would form your basis period for the tax year 2015/16. Your final tax year of trading is 2016/17 and your basis period is the period from 1 November 2015 to 31 August 2016. Remember you can deduct any overlap relief that is still being carried forward when you cease trading.

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How do I get relief for overlap profits when I cease trading?

Any previously unrelieved overlap profits are deducted from your profits in the last tax year.

Example

Louis is carrying forward overlap profits of £12,000. He makes up his last set of accounts for the year to 30 June 2017 that show a profit of £28,000.

Louis ceased trading on 30 June 2017, that is in the tax year 2017/18. If he had not ceased trading he would have been assessed to tax on profits of £28,000. But he can deduct his overlap profits from his taxable profits for the year to 30 June 2017 because he has ceased trading. His assessable profits for 2017/18 become £16,000 (£28,000 less overlap profits of £12,000).

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