The Best CGT Calculator UK
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CGT Payable
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You shouldn’t need a tax advisor on speed dial just to estimate your gains. FinCalc’s CGT Calculator puts the levers in your hands, fast, private, and crystal clear. In one pass, the Capital Gains Tax Calculator turns messy transactions into clean numbers you can act on: net gain or loss, allowance usage, loss offsets, and an estimated liability for your filing year. No emails. No paywalls. No guesswork. We translate disposals, fees, and improvements into a simple outcome so you can decide whether to sell now, stagger across tax years, or harvest losses before the deadline. It’s built for real investors, shares, ETFs, property, crypto, business assets, who want rigor without the headache.
Results are guidance, not advice; you’ll still verify with official rules. But when the math is this clear, you make better calls, faster. Most people overpay or under-plan because they eyeball gains and ignore allowances, timing, and costs. Markets move, tax years roll, and “I’ll sort it later” gets expensive. This tool forces discipline: exact inputs, transparent outputs, and immediate what-ifs, sell today vs next April, split disposals, or use carried-forward losses. A concise summary showing proceeds, allowable costs, net gain/loss, allowance applied/remaining, taxable gain, and an estimated CGT figure, plus reminders about typical reporting/payment timelines for your jurisdiction. Export the snapshot for your records or accountant and iterate scenarios in seconds.
CGT in Plain English
Taxes shouldn’t feel like a riddle. Before we crunch numbers, let’s align on what’s actually taxed, what costs you can deduct, and how rates/allowances change the bill. Once these pieces are clear, the CGT Calculator becomes a straight, decision-making tool, not a guessing game.
What Counts as a Capital Gain
A capital gain happens when you dispose of an asset for more than its cost basis. “Asset” here can mean shares, ETFs/funds, crypto, residential or investment property, business assets, and sometimes collectibles. Your basic formula is: proceeds – allowable costs – cost basis = gain (or loss).
Allowable costs typically include purchase/sale costs (brokerage, exchange fees, legal/agent fees, transfer taxes/stamp duty) and, for property, capital improvements (not routine maintenance). Buying again after you sell property? Price the upfront cost with the Stamp Duty Land Tax Calculator before you reinvest. Dates matter: acquisition and disposal dates determine which tax year you’re in and, in some countries, whether your holding period triggers different rates. Good records are non-negotiable: contracts, statements, invoices, and any improvement proofs.
Allowances & Losses
Most systems include an annual tax-free allowance (or exempt amount). Use it or lose it. You can offset realised capital losses against gains; unused losses often carry forward to future years (rules vary). Timing is strategy: realising a small loss this year can protect a larger gain within the same tax year; splitting disposals across two tax years can preserve more allowance. Where permitted, spouse/civil partner transfers can help utilise two sets of allowances and rate bands, provided they’re genuine transfers, not last-minute paper shuffles. Order of offsets, anti-avoidance rules, and documentation standards differ by jurisdiction, so keep it clean and verifiable.
Tax Bands & Rates (Jurisdiction-Aware Basics)
Rates aren’t one-size-fits-all. Some countries differentiate short- vs long-term holdings; others apply income-based bands (basic/higher/additional) or asset-specific rates (e.g., certain property disposals). The principle is constant: your taxable gain is what’s left after allowances and allowable losses. The CGT Calculator adapts labels, bands, and thresholds by the tax year and region you choose, so you can model reality without memorising tables. Treat its output as an estimate for planning; always verify final figures against official guidance or your accountant before filing. Want a quick personal-side read before you sell? Use the Take Home Pay Calculator to see where your monthly net sits if a disposal changes your tax band.
What the Calculator Actually Does
You bring messy transactions; the CGT Calculator returns clean, decision-ready numbers. It translates buys, sells, fees, and timing into a single snapshot you can act on: net gain or loss, allowance usage, loss offsets, taxable gain, and an estimated bill for your chosen tax year. No fluff, just the financial truth you need to plan, defer, or proceed.
Problems It Solves
Guesswork around allowances, loss offsets, and timing is where people overpay. This section centralises it: sell-now vs next-tax-year scenarios, splitting disposals, harvesting losses before the cut-off, and checking whether spouse transfers (where allowed) actually reduce your bill. Planning a property switch after disposal? Check purchase costs with the Stamp Duty Land Tax Calculator so CGT and SDLT are both budgeted. You’ll see the cash you should ring-fence for tax, and whether a small tweak saves a big number.
Inputs You’ll Use
Asset type, quantity/units, acquisition date/price, disposal date/price, currency/FX (if relevant), and allowable costs (brokerage, exchange fees, legal/agent fees, transfer taxes; for property, improvement, not maintenance, costs). Then add residency/jurisdiction, filing status, the tax year, current-year allowance usage, and any carried-forward losses. Optional fields cover joint ownership splits and spouse/civil partner transfers (where permitted).
Outputs You Get
- Proceeds, cost basis, and allowable costs line-itemed
- Net gain/loss per disposal and aggregated.
- Allowance applied/remaining.
- Loss offsets applied/remaining (with carry-forward visibility)
- Taxable gain by asset class/holding period (where applicable)
- Estimated CGT liability and typical reporting/payment timelines
- A printable/exportable summary for records or your accountant
Sensitivity & What-Ifs
Model the levers that move your liability: sell the same holding in two tranches across tax years; realise a small loss today to shield a larger gain; test spouse transfers to utilise both allowances and bands; compare “hold 12+ months” rules where long-term treatment exists; adjust FX to reflect actual conversion rates. Each scenario shows deltas so you can choose the lowest-cost path, not just the most convenient.
Guardrails & Assumptions
Results are planning estimates, not filings. Jurisdictional rules on allowance ordering, anti-avoidance (e.g., wash-sale–style rules), improvements vs maintenance, and deadline mechanics vary. Keep documentation tight and verify outputs against official guidance or a professional before you submit.
How to Use It + Worked Examples
Two minutes. Five inputs. Clarity. The CGT Calculator is built for rapid what-ifs: you add disposals and costs, we return a clean snapshot, net gain/loss, allowance usage, offsets, and an estimated liability for your chosen tax year. Start simple, then iterate. The goal isn’t a “perfect” forecast; it’s confident decisions before you trade or file.
Quick 5-Step Flow
- Enter your asset and quantity (shares/ETF, crypto, property, business asset).
- Add acquisition date/price and disposal date/price (we’ll place it in the right tax year).
- Input allowable costs: brokerage/exchange fees, legal/agent fees, transfer taxes; for property, add capital improvements (not maintenance).
- Select jurisdiction/tax year, declare allowance usage, add any carried-forward losses, and ownership split/spouse transfer if applicable.
- Review outputs: proceeds, costs, net gain/loss, allowance applied/remaining, taxable gain, and estimated CGT. Save the scenario, then change one lever at a time to see deltas.
Worked Example, Shares/ETF Disposal
Buy: 100 units at £50 = £5,000 cost basis; purchase fee £10.
Sell: 100 units at £70 = £7,000 proceeds; sale fee £10.
Allowable costs total: £20.
Net gain = £7,000 − £5,000 − £20 = £1,980.
The tool then applies your annual allowance (for the selected year), subtracts any carried-forward losses, and estimates tax based on your bands/rates for that jurisdiction. Your summary shows: allowance used/left, taxable gain (if any), and estimated liability, plus a reminder of typical reporting/payment timelines.
Worked Example B, Residential Property
Buy: £220,000 (legal + stamp/transfer: £2,800 added to basis).
Improvements (qualifying capital only): £6,200 over ownership period.
Adjusted cost basis: £220,000 + £2,800 + £6,200 = £229,000.
Sell: £265,000 (agent/legal on sale: £2,500).
Net gain = £265,000 − £229,000 − £2,500 = £33,500.
Rates for property can differ from financial assets in some regions. The calculator applies your allowance, offsets any losses, then estimates liability per local rules for the chosen year. You’ll see a one-page breakdown ready to export for records or your accountant.
What-Ifs That Actually Save Money
- Timing: Split a disposal across two tax years to use two allowances, compare one sale today vs half now/half after the year-end.
- Loss Harvesting: Realise a small loss before the deadline to shield a larger gain, watch the taxable gain drop in the summary.
- Spouse/Civil Partner Transfers: Move part ownership ahead of disposal to utilise two allowances/bands; model both versions to confirm the benefit. After reallocating ownership, verify each partner’s remaining band space using the Tax Bracket Calculator.
- FX Reality: For foreign assets, test a realistic exchange rate vs a conservative one; the tool shows how FX shifts your gain in home currency.
- Improvements vs Maintenance: For property, toggle expenses between “improvement” and “maintenance” (non-capital) to see what truly changes the taxable amount, then keep documentation to match.
Save, Compare, Decide
Lock a baseline scenario, duplicate it, and change one variable, timing, losses, ownership split, or costs. The side-by-side deltas highlight the cheapest compliant path to your goal (reduce tax, smooth cash flow, clean records). Export a PDF/CSV of inputs, assumptions, and results. When the math is transparent, you stop winging it and start managing it.
Real-World Scenarios
Real tax bills come from messy lives, not textbook examples. Use the CGT Calculator to pressure-test moves before you sell, split, or defer. These quick vignettes show how timing, costs, and losses change the liability you actually pay, not the one you fear.
First-Time Investor
You’ve built a small position that’s up nicely. If you dump it all this year, you might blow past your allowance; if you split the sale across tax years, you could stay mostly sheltered. Add brokerage/stamp costs, check any carried-forward losses, and model two scenarios: “all now” vs “half now, half next year.” The delta often pays for itself in minutes of planning.
Property Seller
Your sale price looks great until you realise you didn’t separate capital improvements from routine maintenance. Only improvements increase your cost basis. Enter legal/agent fees on both sides, list qualifying improvements, and see how the taxable gain drops. Then, test completion dates straddling a tax-year boundary, timing can change allowance availability and cash flow.
Crypto Holder
High volatility turns guesswork into overpayment. Batch disposals; attach exchange fees; capture FX where relevant. Harvesting a modest loss today can shield a larger gain tomorrow. Duplicate your baseline, toggle one variable (timing, quantity, loss), and let the summary show the impact, no narratives, just numbers.
Business Asset Sale
Selling equipment or a stake? Documentation drives outcomes. Enter acquisition/disposal details, professional fees, and the ownership split. Where rules allow, simulate pre-disposal transfers to a spouse/civil partner to utilise two allowances/bands, before the sale, not after. Compare “solo sale” vs “split ownership” to see if the structure actually reduces taxable gain.
Deductions, Allowances & Gotchas
Small details move big numbers. This is where most DIY calculations go sideways, mixing up costs, missing allowances, or tripping anti-avoidance rules. Use the CGT Calculator to model both the conservative and the likely reality, then keep documents to prove every input.
Allowable Costs Checklist
Acquisition and disposal costs usually reduce your gain: brokerage/exchange fees, platform dealing charges, legal and agent fees, valuation costs tied to the transaction, and transfer taxes/stamp duty. For property, only capital improvements (extensions, structural upgrades) add to basis; routine maintenance (repairs, cleaning, repainting) does not. Record dates, invoices, and amounts. If a fee is bundled, split it reasonably and note your method. Enter each item line-by-line so the totals in your scenario are audit-ready.
Loss Harvesting & Carry-Forward
Realised losses can offset gains; unused losses often carry forward. Order is key: many systems net current-year gains/losses first, then apply brought-forward losses, and only then touch allowances. Harvesting a small loss before year-end can shield a larger gain, unless anti-avoidance rules bite (e.g., wash-sale/bed-and-breakfast-style rules around quick repurchases). Model both paths: (1) sell/repurchase within the restricted window vs (2) wait out the window or use a close substitute. The calculator will show the taxable delta, so you don’t “save tax” only to disallow the loss.
Ownership, Splits & Spouse Transfers
Who owns what determines who uses which allowance and band. If you hold assets jointly, allocate disposals and costs in the same proportions. Where allowed, spouse/civil partner transfers before disposal can legitimately use two sets of allowances/bands, provided they’re real transfers with matching records (not paper shuffles on settlement day). In the tool, duplicate your baseline, flip the ownership split, and compare liabilities side-by-side.
Timing Nuances You Can Exploit
Tax years create cliffs. Splitting one sale across two tax years can unlock a second allowance and smooth cash flow. For assets with holding-period tiers, crossing the threshold (e.g., from short- to long-term) can materially cut the rate, only if you actually meet the day count and documentation standards. For foreign assets, FX rates at acquisition and disposal affect the home-currency gain; test a realistic vs conservative rate to see sensitivity.
Documentation & Evidence
Keep: trade confirms, broker statements, wallet/exchange logs, legal/agent invoices, contracts, transfer-tax receipts, improvement invoices with dates and descriptions, valuation reports, and FX evidence. Save a scenario export from the calculator (inputs + assumptions) so you can reconstruct your figure later. If you can’t prove an input, treat it as non-allowable in your conservative scenario and see if the liability still fits your plan.
Common Mistakes
Counting maintenance as improvements; ignoring fees; repurchasing too soon and losing a harvested loss; misallocating joint costs; forgetting carried-forward losses; using optimistic FX; and missing the filing/payment deadline. If your plan relies on every optimistic assumption lining up, it’s not a plan; it’s hope. Pressure-test the pessimistic case in the CGT Calculator and make sure you’re still comfortable.
Conclusion
Tax planning shouldn’t be a leap of faith. With FinCalc’s CGT Calculator, you translate trades, costs, allowances, and losses into a simple, decision-ready summary before you sell or file. Model timing across tax years, test spouse transfers where permitted, and see the cash you should ring-fence for payment. Export a clean breakdown for your records or accountant, and rerun scenarios in seconds when markets move. We’re not giving advice; we’re giving clarity, so you avoid missed allowances, disallowed losses, or deadline penalties. The right move is usually obvious once the numbers are honest. Load your disposals, duplicate the baseline, change one lever, and choose the cheapest compliant path. Five focused minutes today can save real money and real stress on filing day. Start now and turn uncertainty into precise, defensible tax planning today.
FAQs
How long should I keep CGT records?
Keep documentation for at least 5–7 years after filing (longer for property/complex cases). That includes trade confirmations, broker/platform statements, legal/agent invoices, transfer taxes, capital improvement receipts, FX evidence, joint-ownership or spouse-transfer records, and loss carry-forward proofs. Export your scenario from the CGT Calculator and store it with receipts so every figure is traceable.
Do gifts or inheritances trigger CGT?
Gifts are often treated as a disposal at market value, which can create a gain even without cash changing hands. Inheritances typically aren’t taxed on receipt, but CGT may apply when you later dispose of the inherited asset. Always obtain valuations and model both baseline and conservative scenarios before acting.
Can I defer CGT just by reinvesting the proceeds?
Generally, no automatic deferral exists for simple reinvestment. Some jurisdictions offer specific reliefs (e.g., business asset rollovers) with strict criteria, time limits, and documentation. Unless a relief explicitly applies, CGT is due on the disposal. Use the CGT Calculator to compare “sell now and rebuy” vs “defer to next tax year.
How are multiple share purchases matched when I sell?
Cost basis depends on local rules: specific identification, FIFO, average cost, or pooling. The method determines which lots you’re deemed to sell and, therefore, your gain. Enter per-lot data using the correct method for your jurisdiction; mismatching rules to inputs can distort results and invite queries.
What affects my CGT the most?
Holding period, tax bands/rates, your annual allowance, and whether you’ve got losses to offset. Costs (brokerage, legal, transfer taxes) reduce the gain if they’re allowable. Run a baseline in the CGT Calculator, then test timing (this year vs next), loss offsets, and spouse transfers (where permitted). Tiny changes in sequence can move the final bill meaningfully.
Can I offset losses from prior years?
In many systems, yes, carried-forward losses reduce current gains after current-year netting. Rules differ on ordering and evidence, so keep confirmations. Add your brought-forward figure to the CGT Calculator and watch the taxable gain drop; if nothing changes, you’ve either misordered the inputs or the loss is not eligible under local rules.
Do fees and improvements really matter?
Absolutely. Allowable transaction costs cut your gain; for property, only capital improvements (not maintenance) add to basis. Itemise each cost in the calculator. If a fee was bundled, apportion it sensibly and keep the invoice; no receipt, no relief.
How do spouse/civil partner transfers help?
Where allowed, a pre-disposal transfer can enable two allowances/bands. It must be genuine (ownership really changes) and correctly documented. Duplicate your scenario, switch the ownership split, and compare liabilities. If the saving is negligible, skip the complexity.
Why are property gains sometimes taxed differently?
Some jurisdictions apply higher or distinct rates to residential property, and reporting windows may be shorter. Model with the right asset type and tax year. If your estimate swings a lot, timing the completion date around the year-end can be a legal, high-impact lever.
Do I owe CGT on foreign assets?
Often yes, but FX and treaty rules matter. Enter proceeds and costs in the original currency; the tool converts to the home currency for the gain. Keep bank/exchange records tied to the dates. If FX sensitivity is high, test a conservative rate and decide whether to defer.