Tax year 2025/26 · Last updated 22 September 2026
Capital Gains Tax Calculator UK
Capital Gains Tax Calculator UK helps UK accountants and clients estimate a common tax figure before turning the work into a managed Remindoo workflow. Figures are for guidance only and should be checked against the latest HMRC rules for the client.
Use the calculator
Template estimate
£20,000
After estimate
£80,000
Worked example
Full detail from the live Remindoo page is shown below.
Calculator FAQs
No. It is a practical estimate for planning and client conversations, not formal tax advice.
Yes. Remindoo turns recurring client obligations into tracked workflows with owners, dates and reminders.
The Capital Gains Tax Calculator UK by Remindoo helps individuals, landlords, and investors estimate how much Capital Gains Tax (CGT) they may need to pay when selling assets such as property, shares, or other investments.
If you sell an asset that has increased in value, you may be required to pay tax on the profit (known as the “gain”). This calculator provides a quick and simple way to estimate your taxable gain and potential CGT liability based on current UK tax rules.
It is an essential tool for financial planning before selling property or investments.
How to Use the Capital Gains Tax Calculator
Using the Capital Gains Tax Calculator is simple:
1. Enter Purchase Price
Input the original price you paid for the asset.
2. Enter Sale Price
Add the price you sold (or plan to sell) the asset for.
3. Add Allowable Costs
Include costs such as:
- Legal fees
- Estate agent fees
- Improvement costs (not maintenance)
- Purchase/sale expenses
4. Select Tax Band
Choose your Income Tax band (basic, higher, or additional rate).
5. View Instant Results
The Capital Gains Tax Calculator shows:
- Capital gain amount
- Tax-free allowance (Annual Exempt Amount)
- Estimated Capital Gains Tax
- Net profit after tax
What Capital Gains Tax Calculator Helps You Do
This Capital Gains Tax Calculator UK helps you:
- Estimate CGT before selling assets
- Understand taxable profit clearly
- Plan property or investment sales
- Avoid unexpected tax bills
- Improve financial decision-making
Who Should Use Capital Gains Tax Calculator?
This Capital Gains Tax Calculator is suitable for:
- Property owners selling second homes
- Buy-to-let landlords
- Share and stock investors
- Business asset sellers
- High-income individuals
- Anyone disposing of chargeable assets in the UK
Key Features of Capital Gains Tax Calculator
- Fast CGT estimates
- Works for property and investments
- Includes allowance calculations
- Easy-to-use interface
- Helps with tax planning
- Free online calculator
How Capital Gains Tax Is Calculated
A simplified calculation:
Capital Gain = Sale Price, Purchase Price, Allowable Costs
Then:
Taxable Gain, Annual Exempt Amount = Taxable Amount
Finally:
Taxable Amount × CGT Rate = Capital Gains Tax
CGT rates depend on your income tax band and type of asset.
Why Use Capital Gains Tax Calculator?
Capital Gains Tax can be complex, especially with property and investment rules. This calculator helps you:
- Plan asset sales efficiently
- Reduce risk of underpaying tax
- Understand real profit after tax
- Improve investment timing decisions
- Stay financially prepared
Use the Capital Gains Tax Calculator UK
Use the Capital Gains Tax Calculator UK by Remindoo to estimate your tax liability, plan asset sales wisely, and make informed financial decisions.
FAQs about Capital Gains Tax Calculator UK
What is a Capital Gains Tax Calculator?
It is a tool that estimates tax payable on profit made from selling assets like property, shares, or investments.
When do I pay Capital Gains Tax?
You pay CGT when you sell an asset that has increased in value and exceeds your tax-free allowance.
What assets are subject to CGT?
Common assets include second homes, buy-to-let properties, shares, and investments.
Is my main home subject to CGT?
Usually not, if it qualifies for Private Residence Relief. However, some exceptions may apply.
What is the CGT allowance?
It is the tax-free amount you can gain each year before paying Capital Gains Tax.
Is this calculator free to use?
Yes, Remindoo Capital Gains Tax Calculator UK is completely free.
Is the result accurate?
It provides reliable estimates, but actual tax depends on HMRC rules and personal circumstances.
Why recording every task matters in an accountancy practice
Accounting firms run on deadlines: VAT returns, payroll, confirmation statements, accounts and Self Assessment. Recording every job as a task, with an owner and a date, is the simplest way to make sure nothing is missed.
Avoid penalties
HMRC and Companies House charge penalties for late filing. A task for every deadline, with an internal date before it, gives the team a buffer.
Nothing depends on memory
Recorded tasks mean work continues when someone is off sick, on leave or has left the firm.
Consistent quality
Subtask checklists make every job follow the same steps and reviews, whoever does the work.
Visibility for managers
Filters by owner, status and deadline show at a glance what is late, what is due and who needs help.
Practical tips from UK practice
- Set an internal deadline two to four weeks before every statutory deadline.
- Use recurring tasks for repeat work such as VAT, payroll and bookkeeping.
- Break larger jobs into subtasks, including a review step.
- Comment on the task instead of by email, so the history stays with the work.
Related Remindoo features
Written and reviewed by Annie, Product Lead at Remindoo. Guidance is general; check current GOV.UK and professional body guidance for your firm.
What UK practices say about Remindoo
Read all reviews on Trustpilot“With Remindoo, everything from the first enquiry to onboarding and ongoing client management is tracked in one place… It saves us hours and gives me, as a practice owner, complete visibility of where the firm stands.”
“The biggest benefit is having clients, tasks, deadlines, workflows, proposals and communication all organised in one place.”
“During my trial, the team were absolutely amazing. They helped onboard my clients, set up my settings and made sure everything was ready for me to use… they made the whole process completely stress-free.”
“It brings client information, tasks, recurring deadlines, workflows and reminders together in one place, giving us much better visibility across the team.”
