UK Pension Bridge Calculator: Early Retirement ISA & GIA

Bridging to your Pension Drawdown Age

This calculator models how an individual can accumulate savings and subsequently draw a target net income from a taxable investment account and a tax-free ISA across a defined bridge period, year by year, until a chosen retirement age.

1. Accumulation phase: If the individual's current age is lower than the age their work stops, the calculator projects the compound growth of their current capital alongside any stated monthly contributions up to the age work stops. This projected value forms the starting capital for the bridge period.

2. Bridge period: Determined by the gap between the age active employment ends (when the bridge starts) and the target retirement age (when pension access begins).

3. Guaranteed income: State Pension income (from State Pension age) and any part-time net salary are applied first, reducing the amount that must be drawn from savings.

4. Personal Allowance harvest: The taxable pool is drawn up to any remaining income tax Personal Allowance not already consumed by guaranteed income. This portion is withdrawn tax-free.

5. ISA drawdown: Any remaining income shortfall is met from the tax-free ISA.

6. Taxable top-up: If a deficit persists, further funds are drawn from the taxable pool. The gross amount required to deliver the specific net sum is calculated after accounting for income tax at the applicable marginal rates.

7. Portfolio growth: Remaining balances in each pool grow at their respective assumed annual rates before the next year begins.

The results panel displays the annual withdrawal from each pool, the income tax paid on taxable withdrawals, and the remaining pool balances for each year of the bridge period.

Calculator Assumptions

All statutory figures (tax rates, band thresholds, the Personal Allowance, State Pension amount and age) are shown in the Standard Calculator Assumptions panel displayed above the calculator and should be reviewed before relying on any output.

The following methodological assumptions also apply:

• Drawdown strategy: An allowance-harvesting approach is used in all scenarios, prioritising the taxable pool up to the remaining Personal Allowance before drawing from the ISA.

• Pool growth: A single fixed annual growth rate is applied to each pool throughout both the accumulation and bridge periods. Actual investment returns will vary.

• Part-time income: Income tax on part-time gross salary is deducted before crediting the net amount against the income target. No National Insurance contributions are modelled.

• Contributions cease at drawdown: Any monthly contributions entered are assumed to cease at the age work stops. No further contributions to either pool are modelled during the drawdown bridge period.

• Life expectancy default: Where no life expectancy is entered, the simulation defaults to age 90.

Calculator Limitations

• Estimates only: All figures are illustrative projections and do not represent guaranteed outcomes.

• Single individual: The simulation models one individual only. Joint or couple planning scenarios are not supported.

• Other income sources: Rental income, dividends, and other taxable income are not modelled. Their presence would affect marginal tax rates and the tax due on any taxable withdrawal.

• Capital Gains Tax: Gains realised within the taxable pool are not assessed for Capital Gains Tax, which may be payable in addition to any income tax shown.

• No benefit interactions: The effect of drawdown income on means-tested state benefits is not modelled.

• No personal advice: This tool is provided for illustrative purposes only and does not constitute financial, tax, or legal advice. Independent guidance from a qualified financial adviser or HMRC is recommended.

Privacy & Data Security

All calculations are executed locally within your browser. We do not track, store, or monitor the figures you enter into this tool.