GIA + ISA Total Tax (20yr)
Dividend tax + CGT, after ISA sheltering
Bond Total Cost (20yr)
Fees + commission + eventual tax
Better Route
Lower lifetime cost wins
A GIA is just a standard UK brokerage account, the kind you'd get from Interactive Brokers, Vanguard, Hargreaves Lansdown or AJ Bell. You hold the ETFs and shares yourself, with no contribution cap and none of the exit penalties or hidden commissions you get with packaged products.
The catch: dividends and reportable income are taxed each year above your £500 allowance, and gains are taxed when you sell above the £3,000 Capital Gains Tax allowance.
An offshore investment bond is technically a life assurance policy, issued from somewhere low-tax like the Isle of Man, Dublin or Luxembourg. Investments inside grow without UK income tax or CGT being applied each year. That's the "gross roll-up" you'll hear pitched.
But the wrapper costs real money: usually 0.5–1.5% per year on top of fund charges, plus 4–8% of your lump sum paid as upfront adviser commission and clawed back through early-year penalties. And when the bond is eventually cashed in, the gain is taxed as income, not as a capital gain.
What you have available to invest today. Defaults to £1,000,000.
If you sold and rebought before becoming UK-resident, this often equals today's portfolio value. A lower basis means more CGT later.
Long-run return for a global equity ETF. VWRA has done around 9% per year since inception; 7% is a sensible planning number.
The slice of total return that arrives as dividends. VWRA pays around 1.8%. The rest comes from the share price going up.
Withdrawals start halfway through the model for every route; the first half is accumulation. £40k on a £1m pot is a 4% withdrawal, the classic rule of thumb.
£20,000 per person per tax year. This model is for one person; a spouse has a separate allowance. Each £1 moved into the ISA is sheltered from dividend tax and CGT for life.
Up to £60,000 gross per year (or 100% of UK earnings). With no UK earnings the limit is £3,600 gross (£2,880 net cost). Basic-rate tax relief is added automatically by the provider.
Minimum access age is 57 from 2028. If retiring at 50, that's 7 years of contributions before you can touch it.
After other pension contributions, tapering or the money purchase annual allowance. Assumes UK residence and age under 75. Keep earnings and this headroom fixed only if that matches your plan.
Carry-forward never increases the earnings limit. Enter only unused allowance you have checked.
Enter any other UK taxable income so the GIA dividend tax is banded properly. Use the buttons to set the tax rate you'd face on an eventual offshore bond surrender.
Pension, rental income, salary, interest: anything taxable before we add the portfolio income.
Expected tax band when the bond is surrendered:
Basic rate: total income up to £50,270
Edit HMRC rates (2026/27 defaults)
Set the ongoing costs for each route. GIA defaults reflect Interactive Brokers plus VWRA. Bond defaults reflect typical offshore bond all-in costs.
Typical offshore bond commission runs 4–8% of the lump sum. The adviser gets paid on day one; you pay for it through higher early-year charges and surrender penalties.
Bond all-in cost: 2.0% + 5% upfront
GIA + Stocks & Shares ISA
Low-cost ETFs held in your own name, with the ISA filled up each year to shelter what it can from tax.
Offshore Investment Bond
Insurance wrapper with gross roll-up, but heavy fees and eventual income tax on the gain.
How each route plays out over time. The GIA's Capital Gains Tax bill creeps up year-on-year as the embedded gain inside each withdrawal grows, though the ISA absorbs a steadily bigger share of the portfolio, which softens the blow. The offshore bond looks tax-free during years 1–20, but the deferred tax surfaces at the end.
| Year | GIA value | ISA value | SIPP value | Tax this year | Bond value | Bond fees this year | Bond deferred tax |
|---|
A Self-Invested Personal Pension (SIPP) can do a lot of work in the years before you retire. If you return to the UK at 50, you have up to 7 years before you can access the pot (minimum age 57 from 2028). During those years, every pound you move from your GIA into a SIPP gets automatic basic-rate tax relief: the provider claims 20% from HMRC and adds it to your pot. A £48,000 transfer from your GIA becomes £60,000 inside the SIPP. Higher-rate taxpayers can claim an additional 20%–25% back via Self Assessment, making the net cost even lower.
Pension carry-forward is easy to miss. If you have UK earnings on return, you can use unused annual allowances from the previous 3 tax years. Your first-year gross contribution is limited by both confirmed available allowances and current relevant earnings, which can move a large part of your taxable GIA into the pension in one go. Even with no UK earnings, you can contribute £2,880 net each year, which the government tops up to £3,600.
At age 57, the drawdown sequencing matters:
- ISA first: withdrawals are completely tax-free and do not count toward your income tax bands.
- SIPP tax-free cash: 25% of whatever you draw from the SIPP is tax-free. The other 75% is taxed as income, but only when you need it.
- GIA up to CGT allowance: sell shares to realise gains up to the £3,000 annual exempt amount.
- Taxable SIPP drawdown: only after exhausting the above, draw the taxable 75% portion, keeping total income within the basic-rate band where possible.
Done in this order, your taxable income stays low and the tax-free pots last longer. The calculator models this automatically: Bed-and-ISA runs every year, SIPP contributions happen during the accumulation phase, and withdrawals follow the sequence above once drawdown begins.
This calculator uses HMRC's published 2026/27 tax rates for the UK General Investment Account route (CGT 18%/24%, dividend tax 10.75%/35.75%/39.35%, CGT allowance £3,000, dividend allowance £500), the £20,000 Stocks & Shares ISA annual subscription limit, the £60,000 SIPP annual allowance (with basic-rate relief at source and confirmed carry-forward, constrained by relevant earnings), and standard offshore bond mechanics (5% tax-deferred withdrawal allowance for 20 years, gain taxed as income at marginal rate on full surrender). It is a planning tool, not regulated financial advice. Bond top-slicing relief, the personal savings allowance, residence-based time apportionment, and remittance basis interactions can all change the picture in specific cases. If you're making a significant decision, get advice from a fee-only chartered tax adviser, not from a salesperson with commission baked into the product.