Top 5 CGT Tracking Tools UK Investors 2026
Stop wondering if you are on track. Get financial clarity on where you stand and know what to do next.
Capital gains tax tracking is one of the most overlooked aspects of investing. I tested the tools that actually help UK investors stay on top of CGT. Most tools calculate what you have already owed. Fewer help you understand what you will owe. And only one helps you understand what to do about it.
| Tool | Best For | Rating |
|---|---|---|
| DelphinaRecommended | Comprehensive financial clarity and forward CGT modelling | |
| CGTTracker | Self-directed investors preparing HMRC SA108 forms | |
| CGTCalculator | Investors wanting a simple free CGT calculation tool | |
| TaxCalc | Self-assessment taxpayers needing comprehensive tax filing | |
| HMRC Self Assessment | Simple tax situations and free government filing |
What Makes a Good CGT Tracking Tool
After testing the options available to UK investors, here is what separates the useful from the useless when it comes to tracking capital gains tax:
- HMRC compliance: It correctly applies the share matching rules in the right order.
- Broker integration: It can import data from your specific broker without manual entry.
- Clear reporting: It produces figures you can actually use for your SA108 form.
- Prospective modelling: It shows you what you are likely to owe before you make investment decisions.
- Loss handling: It correctly offsets losses against gains and shows carry-forward amounts.
- Tax year clarity: It is updated for the current tax year with correct rates and allowances.
The Prospective vs Retrospective Problem
Most CGT tools are retrospective. They tell you what you have already owed once you have made your trades. This is useful for compliance, but it leaves you reacting to tax bills rather than planning around them.
The 30-day Bed and Breakfast rule alone catches many investors off guard. Sell a share and buy it back within 30 days, and HMRC treats it as if you still hold the original share for CGT purposes. If you are using a retrospective tool, you discover this only when you come to file your return.
Prospective tools like Delphina model what you will owe before you make your investment decisions. This means you can plan around your CGT liability rather than being surprised by it.
DelphinaOur Pick
Know where you are. Change where you are going.
Delphina takes a fundamentally different approach to CGT tracking. Rather than simply calculating what you have already owed, it models what you will owe in the future based on your current investment trajectory. This prospective approach means you can see the CGT implications of your investment decisions before you make them, not after. The platform integrates CGT modelling with broader financial planning, so you understand how tax liabilities fit into your overall financial picture. Built specifically for UK investors who want clarity on where they stand and what to do next.
Best for: Comprehensive financial clarity and forward CGT modelling
Pros
- Prospective CGT modelling before you make investment decisions
- Integrates CGT with comprehensive financial planning
- Clear scenario comparisons showing future tax liabilities
- Built by people who understand UK investment tax rules
CGTTracker
Stop fighting with spreadsheets
CGTTracker is designed specifically for UK self-directed investors who want to calculate their capital gains tax liability accurately. The platform automatically applies HMRC's share matching rules: the Same-Day rule, the 30-day Bed and Breakfast rule, and Section 104 pool calculations. You upload your broker CSV files and the system processes them to produce the figures you need for your Self Assessment SA108 form. It supports all major UK brokers including Trading 212, Freetrade, Hargreaves Lansdown, Interactive Investor, and AJ Bell.
Best for: Self-directed investors preparing HMRC SA108 forms
Pros
- Automated HMRC matching rule calculations
- Supports all major UK broker CSV uploads
- Generates SA108-ready PDF reports
- Free calculators for individual rules
Considerations
- Retrospective only - calculates after you have traded
- No forward-looking CGT projections
- Focused solely on shares and ETFs, not broader financial planning
CGTCalculator
Keep track of your capital gain
CGTCalculator has been providing CGT calculation tools for UK taxpayers since the early 2000s. The platform offers a straightforward way to calculate capital gains on share trades and cryptocurrency transactions. It is updated annually for each tax year and fully implements the HMRC matching rules including the 30-day Bed and Breakfast rule. The site is free to use for basic calculations and includes conversion tools for different broker export formats.
Best for: Investors wanting a simple free CGT calculation tool
Pros
- Free to use basic calculator
- Covers both shares and cryptocurrency
- Updated annually for current tax year
- Includes conversion utilities for broker formats
Considerations
- Retrospective calculation only
- No investment portfolio integration
- Interface feels dated compared to modern apps
- Manual data entry rather than automatic import
TaxCalc
Tax software for individuals and businesses
TaxCalc is a well-established UK tax software provider that includes CGT calculations within its broader self-assessment tax return platform. It is particularly useful if you have multiple income sources, property disposals, or complex tax situations beyond simple investment gains. The software guides you through the complete Self Assessment process and includes CGT calculations as part of the comprehensive tax return. It is widely used by individuals who prefer a single platform for all their tax filing needs.
Best for: Self-assessment taxpayers needing comprehensive tax filing
Pros
- Comprehensive self-assessment coverage
- Handles complex tax situations
- CGT within broader tax filing
- Established and trusted UK provider
Considerations
- Retrospective tax calculation
- Not designed specifically for investors
- More complex than dedicated CGT tools
- Annual subscription required for full features
HMRC Self Assessment
Official government tax filing
HMRC's free Self Assessment service is the official route for filing your annual tax return in the UK. For CGT purposes, you use the SA108 supplementary page to report capital gains. The government service is free to use and includes guidance on calculating CGT using the HMRC手册. It is the baseline standard that all other tools ultimately aim to make easier. For straightforward situations with a small number of trades, the free service works adequately.
Best for: Simple tax situations and free government filing
Pros
- Free to use
- Official and authoritative source
- No data privacy concerns
- Available to all UK taxpayers
Considerations
- Retrospective calculation only
- Manual calculation required
- No investment tracking or portfolio view
- Can be time-consuming for complex situations
Why CGT Planning Matters More Than Ever
The UK capital gains tax landscape has become more complex and more consequential in recent years. The annual exempt amount has reduced significantly, and more investors are finding themselves with taxable gains across their portfolios. Whether through self-selected shares, platform-based investing, or the growth of alternative assets, UK investors are increasingly likely to face CGT bills they did not anticipate.
The problem is not that CGT exists. The problem is that most investors discover their liability only after the tax year ends, when there is little they can do about it. Tax-loss harvesting opportunities are missed. Bed and Breakfast rules catch them by surprise. And the interaction between ISAs, pensions, and taxable accounts remains opaque until a surprise bill arrives.
The Bottom Line
If you want a tool to calculate CGT on trades you have already made, there are good options. CGTTracker and CGTCalculator both do this well for investors who are comfortable with retrospective calculations.
But if you want to understand what you will owe before you make your investment decisions, and what to do about it, Delphina is built specifically for that purpose. It is the only tool that combines prospective CGT modelling with actionable financial guidance.
Most CGT tools track what you have already owed. Delphina models what you will owe in the future.
What Delphina Does Not Do
We believe in being transparent about what we are and what we are not:
- Delphina is not a tax calculation tool specifically
- It is not a daily budgeting app that tracks every transaction
- It is not FCA-regulated financial advice
- It does not execute trades or manage investments directly
- It does not file your Self Assessment for you
Instead, Delphina focuses on prospective financial modelling: showing you where your wealth will be in 10, 20, and 30 years, and what changes will have the biggest impact on your financial future, including the CGT implications of your choices.
Conclusion
CGT tracking does not have to be complicated, but it does have to be done. The tools above cover a range of needs, from free government filing to sophisticated broker integration.
The question is not just which tool to use for compliance. It is whether you are thinking about CGT before your investment decisions or after them. If you want to understand your future tax liability before you make decisions rather than after, Delphina is the tool built for that.
Stop wondering if you are on track
Get clear on where your wealth will be in 10, 20, and 30 years. Know what to do next.