What is the Buy / Borrow / Die Calculator?
The Buy / Borrow / Die Calculator is an illustrative UK planning tool that compares two ways of funding yearly spending from an investment portfolio.
One path models borrowing against investments while allowing the portfolio to continue growing. The other models selling investments each year and applying a simplified capital gains tax treatment. The calculator then compares how the two approaches may diverge over time under the assumptions you choose.
It also includes an optional rough inheritance tax sketch and an end-of-horizon comparison between the borrow and sell approaches.
How the Calculator Works?
The calculator starts with a single investment portfolio and applies the same yearly cash draw under two different approaches.
In the borrowing scenario, yearly spending is funded through rolled-up borrowing, with interest added over time. The investment pot continues to grow based on the return assumption entered.
In the selling scenario, investments are sold gradually to fund spending, with a simplified capital gains tax treatment applied to disposals.
At the end of the chosen time horizon, the calculator compares the two paths using the same assumptions. An optional inheritance tax illustration can also be switched on to provide a rough estate comparison.
This is deliberately a simplified educational model. It is designed to help users explore trade-offs and ask better questions, not recreate the UK tax system in detail.
Step 1: Enter Your Portfolio Details
Add your starting portfolio value, original cost basis, yearly cash draw, expected growth rate, and time horizon.
Step 2: Set Borrowing and Tax Assumptions
Choose loan interest assumptions, capital gains tax assumptions, and whether you want to include the optional inheritance tax sketch.
Step 3: Compare Borrowing Versus Selling
Review the year-by-year results, compare debt growth against investment disposals, and explore the end-of-period comparison between the two approaches.
Disclaimer: This calculator provides illustrative projections only and should not be taken as financial, tax, legal, or inheritance planning advice. UK tax rules are heavily simplified and real-world outcomes will vary significantly.
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How different investors might explore Buy, Borrow, Die
Buy, Borrow, Die strategies often sound straightforward online, but the trade-offs can change dramatically depending on portfolio size, spending needs, growth assumptions, and borrowing costs. These examples show how different people might use the calculator to test real-world scenarios.
Daniel, easing into retirement
Daniel wants to understand whether borrowing against his investments for part of retirement could leave more money invested compared with selling assets every year.
- Compares £70k yearly borrowing versus disposals
- Tests 6% growth against 4.5% borrowing costs
- Checks the difference in final estate value
Priya, focused on long-term compounding
Priya wants to see how keeping more of her portfolio invested could affect long-term growth if markets perform reasonably well over decades.
- Models different investment return assumptions
- Explores how rolled-up interest grows over time
- Uses the comparison panel to stress-test outcomes
Marcus, thinking about inheritance
Marcus is less concerned about maximising spending and more interested in how borrowing versus selling could affect what may eventually pass to family.
- Turns on the rough IHT illustration
- Compares estate values under both approaches
- Uses the model before speaking to advisers
What is the Buy / Borrow / Die Calculator?
The Buy / Borrow / Die Calculator is an illustrative UK tool that compares borrowing against investments with selling investments over time to fund yearly spending. It helps users explore how portfolio growth, borrowing costs, capital gains tax, and simplified inheritance tax assumptions may interact under different scenarios.
What does the Buy / Borrow / Die Calculator compare?
It compares two simplified ways of funding yearly spending from investments: borrowing against the portfolio or selling investments gradually over time.
What does “Buy, Borrow, Die” mean?
The phrase is commonly used to describe a strategy where investors buy assets, borrow against them rather than selling, and eventually pass remaining assets to their estate. This calculator explores parts of that idea in a simplified UK context.
Does the calculator model UK tax rules fully?
No. Capital gains tax and inheritance tax are simplified heavily. The model does not fully include exemptions, spouse relief, trusts, gifts, reporting requirements, or detailed estate planning rules.
What happens in the borrowing scenario?
The borrowing path assumes spending is funded through rolled-up borrowing, with interest added over time while investments remain invested.
What happens in the selling scenario?
The selling path assumes investments are sold gradually to fund yearly spending, with a simplified capital gains tax treatment applied to disposals.
Does the calculator include inheritance tax?
It includes an optional rough inheritance tax sketch using simplified assumptions. It should not be used for estate planning decisions.
Does the calculator recommend borrowing instead of selling?
No. The purpose is educational. It is designed to help users explore trade-offs and compare outcomes under different assumptions.
Does this include lender rules or borrowing limits?
No. The model does not include affordability checks, amortisation, margin calls, or lender-specific rules.
Does it include inflation or fees?
No. The calculator does not fully model inflation, platform fees, adviser charges, or detailed tax reporting.
Can I export the results?
Yes. The calculator includes CSV export functionality and may optionally use an email signup flow depending on site configuration.
Is my information stored?
Inputs may be remembered locally in your browser. CSV export and email signup are separate from the calculation itself.
Trust and education
Certified Money First Aider®
These calculators are built by a Certified Money First Aider to help you think more clearly about money and time. Money First Aid® is about practical, non-judgemental support for financial wellbeing. The calculators can certainly help you make informed decisions, but they are not regulated financial advice.
