CGT Loss Harvesting Calculator

Loss harvesting is the practice of deliberately realising capital losses to reduce the Capital Gains Tax (CGT) you owe on gains in the same tax year. In 2026/27, every UK taxpayer has an Annual Exempt Amount (AEA) of £3,000 — only gains above this are taxable. But before the AEA is even applied, any allowable capital losses in the same tax year are netted against gains. This means a £10,000 gain combined with a £5,000 loss produces a net gain of £5,000, from which the £3,000 AEA is subtracted, leaving only £2,000 taxable. CGT rates for 2026/27 are: 18% (basic-rate taxpayers) or 24% (higher/additional-rate taxpayers) for residential property; 10% or 20% for other assets including shares, crypto, business assets and second homes. Unlike the old system that had different property and non-property rates, since October 2024 all assets except residential property use the same 10%/20% structure. This calculator allows you to input any number of disposals — shares, funds, crypto, property — and toggle each as a gain or loss. It computes total gains, total losses, net gain, taxable gain after the AEA, and the final CGT bill at your chosen rate. If your losses exceed your gains, the unused portion is shown as a carry-forward amount you can set against future gains (reportable to HMRC within 4 years of the tax year end). Strategic loss harvesting is particularly useful in the final weeks of the tax year (before 5 April). You might sell a fund sitting at a loss to offset gains from a profitable share disposal earlier in the year, reducing or eliminating your CGT bill. The 30-day bed-and-breakfast rule prevents you buying the same investment back within 30 days of selling, but you can buy a similar fund immediately or use a bed-and-ISA strategy to shelter the position going forward. This tool covers simple disposal scenarios. It does not handle Section 104 share pooling, HMRC matching rules for share buybacks within 30 days, Business Asset Disposal Relief calculations, Private Residence Relief on property, or non-resident CGT. Report UK residential property disposals within 60 days via HMRC online service; all other gains go on your Self Assessment return by 31 January following the tax year.