CII R03 Personal Tax Calculations: Income and Gains Workflow

Table of Contents

• • Income tax: use one computation order
• • Worked income-tax example
• • Capital gains: separate the gain from the tax
• • What to write beside every figure
• • Common R03 calculation traps
• • Limits of the tool and example

For R03, the order matters as much as the arithmetic. First identify the taxpayer and tax year. Then classify the income or disposal, calculate the taxable amount, apply allowances in the correct place, allocate bands and only then apply the rates.

The official CII R03 unit page should be your starting point for the syllabus edition that applies to your exam. CII states that its 2026/27 R03 edition applies to exams from 1 September 2026 to 31 August 2027. If your exam is before that window, use the edition assigned to your sitting even where a figure happens to be unchanged. For 2026/27 reference figures, use the current GOV.UK Income Tax rates and allowances and GOV.UK Capital Gains Tax rates. Do not mix these with figures from an earlier study text.

Income tax: use one computation order

For a simplified non-savings-income calculation:

1. total the relevant income;
2. deduct any reliefs that produce net income;
3. establish adjusted net income for allowance tests;
4. calculate the available personal allowance;
5. deduct the allowance to find taxable income;
6. allocate taxable income across the rate bands; and
7. apply the appropriate rates.

For 2026/27 in England, Wales and Northern Ireland, the standard personal allowance is £12,570. The basic-rate band is £37,700, followed by higher-rate tax up to the additional-rate threshold. The non-savings rates are 20%, 40% and 45%.

The allowance taper is:

reduction in personal allowance = (adjusted net income − £100,000) ÷ 2

Apply it only when adjusted net income exceeds £100,000, and do not reduce the allowance below zero. The standard allowance is fully lost at adjusted net income of £125,140.

Worked income-tax example

Assume an individual in England has £55,000 of non-savings income in 2026/27, no deductible reliefs and the full personal allowance.

1. Taxable income: £55,000 − £12,570 = £42,430
2. Basic-rate portion: £37,700 × 20% = £7,540
3. Higher-rate portion: (£42,430 − £37,700) × 40% = £1,892
4. Illustrative income tax: £7,540 + £1,892 = £9,432

This example intentionally excludes savings income, dividends, the High Income Child Benefit Charge and other adjustments. Adding those facts can change the computation order or the available bands.

Capital gains: separate the gain from the tax

First calculate the gain:

disposal proceeds − allowable acquisition and disposal costs − allowable enhancement expenditure

Then apply the tax steps:

1. combine gains and allowable losses as instructed;
2. apply any reliefs in the required order;
3. deduct the available annual exempt amount;
4. place the remaining taxable gain above taxable income; and
5. apply the rate to each part of the gain.

For an individual in 2026/27, the annual exempt amount is £3,000. The main individual CGT rates are 18% and 24%. The lower rate applies only to the part of the taxable gain that fits within the unused basic-rate band.

Continue the income-tax example and assume a chargeable gain of £10,000 after allowable costs and losses, with no relief available.

1. Taxable gain: £10,000 − £3,000 = £7,000
2. The individual’s taxable income already exceeds the £37,700 basic-rate band.
3. The full £7,000 is therefore charged at 24%.
4. Illustrative CGT: £7,000 × 24% = £1,680

The income tax and CGT liabilities are calculated separately, but taxable income determines how much of the basic-rate band remains for the gain.

Use the tool as a checking sheet for a deliberately simple 2026/27 scenario. Enter the requested income and gain figures, inspect the allowance and band allocation, and then reproduce the result on paper. If your answer differs, check the sequence before checking the multiplication.

What to write beside every figure

Numbers become easier to retrieve when the label travels with them. Do not write “£3,000” on a flashcard by itself. Write “2026/27 individual CGT annual exempt amount: £3,000.” Apply the same rule to:

• the tax year;
• the jurisdiction;
• the type of income;
• the taxpayer type;
• the allowance, rate or band; and
• any condition that changes its availability.

This prevents confusion between the CGT annual exempt amount, the inheritance-tax annual gifts exemption and unrelated limits with similar values.

Common R03 calculation traps

• Deducting the personal allowance from tax: it reduces income before rates are applied; it is not a tax credit.
• Ignoring adjusted net income: the standard allowance cannot be assumed above £100,000.
• Charging the whole income at the marginal rate: each slice remains in its own band.
• Applying CGT to the gross disposal proceeds: calculate the gain and deduct the available exemption first.
• Giving the gain a fresh basic-rate band: taxable gains sit above taxable income.
• Mixing jurisdictions: Scottish non-savings bands differ, even though other UK rules may still be relevant.
• Mixing years: a correct old figure is still wrong when the examined tax year has changed.

The broader CII R03 Personal Taxation study plan explains how to organise the full syllabus, including inheritance tax, National Insurance, investment taxation and advice application. Use this workflow for calculation practice inside that plan.

Limits of the tool and example

This is an educational revision aid, not tax, legal or financial advice. The calculator is simplified and does not cover Scottish non-savings rates, savings and dividend ordering, every allowance or relief, residence, trusts, jointly owned assets, business disposals, carried-forward losses, reporting deadlines or all rounding conventions. Use the facts supplied in the question and verify current law through official sources before any real-world action.