How Losses Brought Forward Work

How do losses brought forward work in TinyTax? If your company made a loss in previous years, you can use those losses to reduce this year's tax bill. This guide explains how to enter losses, how they reduce your tax, and what carries forward.

What Are Brought Forward Losses?

When your company makes a loss, you can carry it forward to future years. These "brought forward losses" offset future profits, reducing your corporation tax.

Example:

• 2023-24: Company made a £20,000 loss
• 2024-25: Company made a £50,000 profit
• Brought forward loss: £20,000
• Taxable profit: £30,000 (£50,000 - £20,000)

Where to Enter Losses

In the Tax computation section of the form, find the Losses heading near the top and click Show ▾ next to it. You'll see:

Enter the total losses from previous years that you want to use this year. The Losses chevron opens automatically next time if it has any data inside (and shows a small count badge — e.g. "Losses (1)" — so you can see at a glance that there's a value stored).

How Losses Reduce Your Tax

Key Box Numbers for Losses

First Year Companies

On a company's first accounting period in TinyTax, the losses field is hidden — a genuine first-year company has no prior period to bring losses from.

Filed your first period elsewhere? (e.g. another software package or accountant)

If your first period was filed outside TinyTax, we won't have a record of it, so your second period may show as a first year and hide the losses field. What to do depends on whether this period makes a profit:

• This period is loss-making: you don't need the field yet. Brought-forward losses can only be set against a profit, so there's nothing to enter on a loss return. Your earlier loss stays available, and this period's loss is recorded automatically (Box 780). Once this return is filed and accepted, TinyTax will recognise the next period as a continuation and the losses field will appear.
• This period is profitable and you need to use an earlier loss now, but the field is hidden: reply to support and we'll help — there's a way for us to register your prior filing so the field unlocks.

Partial Use of Losses

You don't have to use all your losses at once:

Example:

• Losses available: £100,000
• This year's profit: £30,000
• Losses used: £30,000 (reduces profit to zero)
• Remaining losses: £70,000 (carry forward to next year)

Current Year Losses

If your company is making a loss this year:

1. Your profit figures will show a negative number
2. TinyTax calculates the loss automatically

1. Use these losses in future profitable years

• Use current year losses against past profits (via TinyTax)
• Get a tax refund for losses (special rules apply - ask an accountant)

Loss Restrictions

You can only offset losses against profit

If your profit is £30,000, you can only use £30,000 of losses - not more. The rest carries forward.

Group relief

If your company is part of a group, losses can sometimes be surrendered between companies. TinyTax doesn't handle group relief - speak to an accountant.

Where to Find Your Loss Figures

Check these sources for your brought forward loss amount:

Extended Periods (>12 months)

For accounting periods longer than 12 months, TinyTax splits into two CT600s:

1. Period 1: Uses your brought forward losses first
2. Period 2: Uses any remaining losses, plus any losses generated in Period 1

What If Losses Were Not Entered in a Previous CT600?

If you filed a CT600 without entering losses brought forward that were available, the computations document for that period will correctly show zero losses carried forward — because no losses were recorded in the return. The two options below apply when you want to correct this.

Option 1: Amend the prior CT600 (recommended)

Amend the earlier return to enter the losses in the Losses brought forward from prior years field. This will:

• Reduce that period's taxable profit (potentially to zero)
• Correctly show the carried-forward balance for the following period
• Potentially generate a corporation tax refund if you paid CT on a higher profit than necessary

Option 2: Enter the full original loss balance in the next CT600

If you prefer not to amend, enter the full original loss balance (not a reduced amount) as losses brought forward in the current period. Because the losses were not officially used in the prior return, the complete amount remains available.

Common Questions

"The losses field is hidden"

This happens when:

• It's your company's first accounting period in TinyTax (including a second period where the first was filed elsewhere — see "First Year Companies" above)
• You're filing as Dormant (no losses for dormant companies)
• The field hasn't loaded - try refreshing the page

"Box 160 is showing 0 in red and won't let me type in it"

That's expected. Box 160 is a calculated field, not an input. It's 0 because the period you're filing has no taxable profit to set the loss against — you can't use a brought-forward loss when there's no profit. Enter brought-forward losses in the editable Losses brought forward from prior years field (in the Tax computation section), and only in a period that makes a profit. If this period is itself a loss, you don't need to enter anything — your losses stay available.

"I've entered my loss but it isn't showing on the CT600 form"

"I entered losses but my tax didn't change"

Check that:

• You have profits to offset (losses can't make tax negative)
• The figure saved correctly (check it's still showing)
• The tax computation section updated

"How do I know what losses I have?"

"Should I enter pre-April 2017 and post-April 2017 losses separately?"

No — there is a single field for all trading losses brought forward, and you enter the total of your pre-April 2017 and post-April 2017 losses combined.

The April 2017 loss reform (Finance (No. 2) Act 2017) changed how HMRC allows those losses to be used — post-April 2017 losses are more flexible and can be set against total profits, not just same-trade profits — but the CT600 form and TinyTax's input both still use a single field for the combined total. TinyTax applies the post-2017 flexibility rules automatically based on the total figure you enter.

For the vast majority of small companies (profits well below £5 million), the pre/post-2017 distinction makes no practical difference to the tax saved, as there is no restriction on full relief.

"Can I claim losses from many years ago?"

Verification

After entering losses, check the Tax Computation shows:

• Losses brought forward: Your entered amount
• Losses applied: Amount used against this year's profit
• Losses remaining: What carries forward to next year

Loss-Making Company This Year?

If you're making a loss this year (profit is negative):

1. Enter your P&L figures as normal (showing the loss)

1. The loss appears in "Losses to carry forward"
2. Use it in future years when you're profitable

Still Have Questions?

Last updated: February 2026