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What is box 235 on the CT600? (and where trading losses actually go)

Reviewed by Lee Jones, Founder · Updated 16 July 2026
The short answer

Box 235 is called "Profits before other deductions and reliefs". It is a running total: all the different kinds of money your company made in the year, added together, before the last few tax reliefs are taken off. One thing it is not: it is not where a loss goes. If your company lost money this year, the loss is recorded in box 780, and box 235 will often just say £0.

Official source. This guide is a plain-English summary of official GOV.UK guidance, not advice. The authoritative source is The Company Tax Return guide on gov.uk. Always rely on that over our summary.

What goes in it?

By the time you reach box 235, the form has already asked about each kind of income separately: your trading profit after old losses (box 165), any bank interest (box 170), any rental income (box 190), and a few rarer kinds. Box 235 simply adds those lines together, minus a couple of specific deductions that sit just above it.

For most small companies it is one easy sum. Say your company made a £20,000 trading profit and earned £150 of interest on its savings. Box 235 is £20,150. If trading profit is your only income, box 235 is just your trading profit again.

It is "before other deductions and reliefs" because the section straight after it takes things off; a later box (box 315) holds the figure your tax is worked out on.

What if my company made a loss?

A trading loss means that, after the tax rules have adjusted your accounts, your company's costs for the year were bigger than its sales. Plenty of healthy companies have one, and the form has a proper home for it. In a loss year you put £0 in the trading profit box (box 155) and the full loss in box 780. If the loss was your only activity, box 235 ends up at £0 too.

Recording the loss is genuinely worth doing, because a loss is not nothing. It is a credit against future tax. If it is not used any other way, it carries forward while the trade keeps going and shrinks a future year's bill. A £5,000 loss this year knocks £5,000 off a future profit, and at the 19% rate for small profits that is £950 off a future tax bill. You can also set the loss against other profits made in the same year (box 275), or carry it back against last year's profits.

One plain warning: the claim for a loss forms part of your tax return. If you file and only later realise the loss never went on, you can usually still claim it by amending the return or writing to HMRC, but only within two years of the end of the loss year, so the safe move is to record it now. Box 780 is you telling HMRC "remember this £5,000, it is mine".

What usually goes wrong?

The big trap is the sentence "we made a loss, so there is no tax, so there is no return". The first two parts may be true. The third is false and expensive. You must still send a Company Tax Return if you make a loss or have no Corporation Tax to pay. Skip it and the late penalty is £200 from the very first day.

The quieter mistake is filing at a loss but leaving box 780 empty, so the loss is never claimed. You lose nothing today, but a future profitable year pays more tax than it needed to.

Do I have to work this out myself?

No. Any filing software adds up box 235 for you, and it should route a loss to box 780 without you knowing the box numbers exist. SimpleReturns works the loss boxes out for you from your bank statement and a few plain-English questions, loss years included, and shows you every figure to check before anything is sent to HMRC. It is £99 flat, and that covers both filings: the tax return to HMRC and the accounts to Companies House.

If your company is part of a group, or you want to share losses between group companies, an accountant is the right call for that, plainly.

Common questions

My company made a loss. Do I still need to file a return?

Yes. A loss year still needs a Company Tax Return, even though there is no tax to pay. Filing it is also how the loss gets recorded so it can save you tax later.

Can a loss get me money back from HMRC?

Sometimes. If your company paid Corporation Tax last year, you can usually carry this year's loss back against last year's profits, which can mean a repayment. An accountant is a sensible choice if the numbers are large.

Does the loss disappear if I do not use it straight away?

No. If you do not use it this year or carry it back, it carries forward to future years while the trade keeps going. Just make sure it goes on a return; loss claims generally need sorting within two years of the end of the loss year.

Filing at a loss and want it done right?

SimpleReturns works out the loss boxes for you, from your bank statement and a few plain-English questions, and lets you review the lot before anything goes to HMRC or Companies House. Free to start, no card needed, £99 flat when you file.

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And if you are carrying a loss back for a refund or sharing losses in a group, we will say plainly when an accountant is the better route.

General guidance, not advice. This guide explains how the rules generally work for small UK limited companies. It isn't tax advice for your specific situation, if you're unsure, check with us or an accountant.