Capital Gains Tax on a Property Sale: Rates, Deadlines and the Reliefs Worth Checking

Capital Gains Tax is the bill that catches property sellers most by surprise — not because the rate is a mystery, but because the deadline is short, the reliefs are easy to miss, and the line between a capital gain and taxable trading profit is not always where people assume it is. Here is the shape of it.

What counts as a gain, and what does not

CGT is charged on the gain — sale proceeds minus original cost, minus qualifying costs of acquisition and disposal (legal fees, agent fees, SDLT paid on purchase), minus the cost of capital improvements (an extension, not a repaint). Routine maintenance and running costs are not deductible against the gain; they may already have been deducted against rental income if the property was let.

Your main residence is usually exempt under Private Residence Relief (PRR) — but only for the period(s) it was genuinely your only or main home, plus a final period of ownership regardless of use at that point. A second home, a buy-to-let, or a development property does not get this relief on the gain relating to periods it was not your main residence.

The rates, and why they are not one number

The rate you pay on a residential property gain depends on your total taxable income for the year the gain arises. Basic-rate taxpayers pay a lower rate on the gain up to the point their income and gain together use up the basic-rate band; anything above that — and all of a higher or additional-rate taxpayer's gain — is taxed at the higher residential property rate. Everyone gets an annual exempt amount before any CGT is due at all, though this allowance has been reduced significantly in recent years and is now modest.

Because the rate depends on your total income for the year, the timing of a sale relative to other income (a bonus, a pension lump sum, closing a business) can genuinely change how much tax is due on the same gain.

The 60-day reporting deadline

This is the point that catches the most people out. If you are UK resident and sell (or otherwise dispose of) a UK residential property with a taxable gain, you must report the disposal and pay an estimate of the CGT due within 60 days of completion, using HMRC's dedicated online CGT service — not your annual Self Assessment return, though the figures are reconciled there later.

Miss the 60 days and HMRC applies an automatic late filing penalty, plus interest on the tax, even if your eventual Self Assessment return shows the correct figure was paid in full. Solicitors do not generally handle this for you as part of conveyancing — it is the seller's own responsibility, and it needs a completed gain calculation in hand well before the clock runs out.

Property developers: gain or trading profit?

This is the distinction that causes the most disputes with HMRC. A property held as a long-term investment and sold occasionally is normally a capital gain. A property acquired with the clear intention to develop and sell at a profit — particularly where this is repeated, financed short-term, or run alongside other development activity — looks to HMRC like trading, not investing.

The consequences of getting this wrong are significant: trading profit is taxed as income (up to 45% for individuals, plus potentially Class 4 National Insurance), with no CGT annual exemption and none of the CGT-specific reliefs. HMRC applies a set of long-standing tests — the “badges of trade” — covering intention at purchase, frequency of transactions, how the purchase was financed, and what work was done before sale. Getting the structure and the paperwork right from the outset, before the first sale, is far easier than arguing the point after HMRC opens an enquiry.

Reliefs and planning points worth checking

• Private Residence Relief and the final-period exemption on a former home, including apportionment where part of the property was let (lettings relief is now far more restricted than it once was, so do not assume it applies).
• Spousal transfers — transfers between spouses and civil partners are generally at no gain/no loss, which can be used to make full use of both partners' annual exempt amounts and basic-rate bands before a sale.
• Timing the disposal across tax years where a sale can reasonably be delayed or brought forward, particularly around other income events.
• Capturing every allowable cost — genuine capital improvements are often under-claimed because records were not kept at the time.
• Incorporation relief for genuine property partnerships transferring a portfolio into a company — see our note on this in the Section 24 article, since the two questions usually arrive together.

None of these apply automatically, and several interact with each other in ways that change the answer — which is exactly why the calculation is worth doing properly rather than estimating.

Why this needs doing before completion, not after

Unlike Income Tax, where planning can often happen after the tax year ends, CGT on property is largely fixed by the terms of the sale and the 60-day clock starts the moment it completes. Reliefs that depend on structure — who owns the property, how it has been used, whether a transfer between spouses happens first — need to be actioned before exchange, not discovered afterwards. We see this most often with developers and investors across Liverpool, Manchester and Cheshire who come to us once contracts are already exchanged, by which point several of the better options are no longer on the table.

Common questions

How much Capital Gains Tax do I pay when I sell a rental property?

For UK residential property, individuals pay CGT on the gain after deducting the cost, buying and selling expenses, and qualifying improvement costs. The rate depends on your total taxable income for the year — basic-rate taxpayers pay a lower rate on residential property gains, higher-rate taxpayers pay a higher rate, and where a gain straddles the threshold, part is taxed at each rate.

What is the 60-day CGT reporting deadline?

UK residents who sell a residential property with a taxable gain must report and pay the estimated CGT within 60 days of completion, using HMRC's dedicated online service — separate from and in addition to your Self Assessment return. Missing the deadline triggers automatic penalties and interest, even if the tax itself is later confirmed correct on your return.

Do property developers pay Capital Gains Tax or Income Tax on profit?

It depends on intent and pattern of activity. A genuine long-term investment property sold occasionally is usually a capital gain. A property bought with the clear intention of developing and selling for profit — especially where this happens repeatedly — is more likely to be treated by HMRC as trading income, taxed as profit rather than a capital gain, with no CGT annual exemption and potentially National Insurance.

Can I get Private Residence Relief on a property I sometimes lived in?

Private Residence Relief covers the period(s) a property was genuinely your only or main residence, plus a final period of ownership regardless of use. Partial letting or periods of absence can restrict the relief, and the rules on what counts as genuine occupation (not just brief or nominal residence) are strictly applied. Each case needs its own calculation.

This article is general information, not personal tax advice, and tax rules change. Your own position depends on facts we cannot see from here — please take advice before acting on anything above.

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