The capital gains tax allowance for the 2017/18 UK tax year (6 April 2017 to 5 April 2018) was £11,300 per individual. Gains up to that figure were tax-free, and only the profit above it was charged to CGT at rates that depended on the type of asset and your income band. If you’re filing a late return, amending an earlier one, or checking a past transaction, the numbers below are the ones that applied.
How the £11,300 Allowance Worked
The exempt amount covered your combined gains from every disposal in the year, not each sale separately. Sell shares in June 2017 for a £4,000 profit and a second home in January 2018 for a £9,000 profit, and your total gain is £13,000. Only £1,700 was taxable.1GOV.UK. Capital Gains Tax Rates and Allowances
Unused allowance could not be carried forward. If your gains for 2017/18 came to only £3,000, the remaining £8,300 disappeared on 6 April 2018. Personal representatives handling a deceased person’s estate received the same £11,300 for the tax year of death.
Rates on Gains Above the Allowance
Once your gains passed £11,300, the rate depended on the asset and on where your taxable income and gains sat relative to the basic rate band:
- Most assets, including shares, valuables, and business assets: 10% within the basic rate band, 20% above it.
- Residential property such as second homes and buy-to-lets: 18% within the basic rate band, 28% above it.
Many people paid a blended rate. A basic rate taxpayer with £5,000 of basic rate band left and a £10,000 taxable gain on a rental property paid 18% on the first £5,000 and 28% on the remainder. Gains on your main home were usually exempt under Private Residence Relief, so the residential rates mainly affected additional properties.
Entrepreneurs’ Relief for Business Disposals
Business owners who sold all or part of a qualifying business in 2017/18 could claim Entrepreneurs’ Relief and pay a flat 10% on qualifying gains, up to a lifetime limit of £10 million. It covered sole traders selling their business, company directors selling shares in their personal trading company, and partners disposing of their share of a partnership. Ownership and trading conditions had to be met for at least 12 months before the sale. A higher-rate taxpayer with a £500,000 qualifying gain paid £50,000 rather than £100,000.
Trust Allowances
Trusts had their own, smaller exempt amount. Most trusts received £5,650 for 2017/18, exactly half the individual figure. Where one settlor had set up multiple trusts, the £5,650 was divided equally between them, with a floor of £1,130 per trust.1GOV.UK. Capital Gains Tax Rates and Allowances
Trusts for disabled or vulnerable beneficiaries were the exception: trustees could use the full £11,300. Gains above the exempt amount were taxed at 20% for most assets and 28% for residential property.
Exemptions That Kept Gains Out of the Calculation
Your Main Home
You owed no CGT on selling your home if it was your only or main residence throughout ownership, you hadn’t let part of it out (a lodger was fine), no part was used exclusively for business, and the grounds were under 5,000 square metres. Private Residence Relief applied automatically with nothing to claim.2GOV.UK. Tax When You Sell Your Home
Partial relief was usually available where some conditions weren’t met. Under the rules in force for 2017/18, the final 18 months of ownership always counted as occupation, even if you had moved out.3GOV.UK. HS283 Private Residence Relief
ISAs and PEPs
Gains on investments inside an Individual Savings Account or a Personal Equity Plan were fully exempt. No reporting was needed and the gains did not count toward the £11,300 threshold.4GOV.UK. Capital Gains Manual – CG57600
Using Both Spouses’ Allowances
Spouses and civil partners living together each had their own £11,300. Where they jointly owned an asset, each share used its owner’s exempt amount, sheltering up to £22,600 from a single disposal.
Transfers between spouses happened on a no-gain, no-loss basis, so moving half an asset to the other person before selling brought both allowances into play without triggering CGT at the point of transfer.5GOV.UK. Capital Gains Tax – Gifts to Your Spouse or Charity The no-gain, no-loss treatment did not apply if the couple had separated and did not live together at all during the tax year, and it did not apply where goods were transferred specifically for the other spouse’s business to sell on.
Capital Losses
Losses did not expire the way the annual exempt amount did. A loss on a 2017/18 disposal first offset gains from the same tax year. Anything left over could be carried forward indefinitely and set against future gains.6GOV.UK. Capital Gains Tax – If You Make a Loss
Carried-forward losses only had to be used down to the annual exempt amount, preserving the rest. Current-year losses had to be fully offset even where that wasted part of the £11,300.
Reporting to HMRC
You needed to report gains through a Self Assessment return if your total gains exceeded £11,300 or your total sale proceeds exceeded four times that figure (£45,200). The deadlines for 2017/18 were:
- Paper returns: 31 October 2018.
- Online returns: 31 January 2019, which was also the payment deadline.
Missing either deadline brought an automatic £100 penalty, even if no tax was due, with further penalties and interest accruing on unpaid tax.7HM Revenue & Customs. 100 Days Left to File 2017/18 Tax Return
The return had to include the asset type, acquisition and disposal dates, sale proceeds, original cost, and any allowable deductions such as improvement costs or professional fees. HMRC required non-business individuals to keep the underlying records for at least 22 months after the end of the tax year, though CGT records often need to be kept far longer because the original acquisition cost may be needed years later when the asset is eventually sold.