Builder on £45,000

Sole Trader. Age 38. Pension preference: modest.

Every figure on this page is computed at build time by the same engines that power the live salary–dividend split, take-home and SIPP optimiser calculators. Inputs come from a single CSV row; outputs come from the engines. No static lookup tables, no hand-coded numbers.

Net cash

£34,724

Pension

£0

Effective rate

17.8%

Marginal rate

26%

Worked example: Builder, 38, £45,000 of turnover

Picture a builder aged 38 for the 2026/27 tax year, trading as a sole trader with £45,000 of turnover. The optimisation goal for this profile is a balance of cash and pension contribution (modest pension preference, treating £1 of pension as £0.50 of cash for the search).

Running the engine for this exact profile:

Taxable profits after the trading-allowance choice: £42,750
Income tax: £6,036
Class 4 NI: £1,811
Class 2 (voluntary): £179
Net cash: £34,724 (17.8% effective on turnover)
Same turnover as a Ltd Co (no pension): £34,081 — a gap of £643 in favour of staying a sole trader

The vignette is hypothetical but the numbers are not — every figure above was produced by the same engine code that powers the live BracketMath calculators, run at build time on inputs drawn from a single CSV row.

The numbers, line by line

Turnover	£45,000
Taxable profits	£42,750
Trading allowance vs actual expenses	Actual expenses
Income tax	£6,036
Class 4 NI	£1,811
Class 2 NI (voluntary)	£179
Net cash (year)	£34,724
Net cash (monthly)	£2,894
Hours-equivalent at NLW (£12.21/hr)	2,844 hrs
Effective rate	17.8%
Same turnover as Ltd Co (no pension)	£34,081
Incorporate vs stay sole trader	£643 for staying sole trader

Why this scenario is different

Compared to the closest peer profile — Freelance writer at £45,000 — this scenario sits £0 higher on gross income. That moves net cash by +£0, the pension contribution by +£0, and the effective rate by +0%. The effective rate moves only modestly — both scenarios sit inside the same binding tax band. Taxable profits change from £42,750 to £42,750 (after the trading-allowance / actual-expenses choice).

Questions this scenario raises

What expenses can I deduct as a sole trader?

"Wholly and exclusively" business costs — equipment, software, professional insurance, travel to non-permanent workplaces, training that maintains existing skills, a proportionate share of home-office costs (HMRC simplified flat rates available), and accountancy fees. Personal commuting, entertainment, training to acquire new skills, and clothing (unless protective / uniform) are not deductible.

How much can I put into pension this year?

The 2026/27 pension Annual Allowance is £60,000. Below £260,000 of adjusted income the full £60,000 Annual Allowance is available. Carry-forward of unused AA from the last three tax years is available subject to membership-in-each-year rules.

How do I avoid the 60% taper?

For a salaried employee: salary sacrifice into pension. For a Ltd Co director: employer pension contribution. For a sole trader: personal pension contributions (which reduce adjusted net income). The taper-zone marginal of 60% means each £1 of pension contribution effectively costs the saver 40p of foregone cash — the strongest tax shelter the UK code currently offers.

Does this calculation include student loan repayments?

No. Student Loan repayments (Plan 1 / 2 / 4 / 5 / Postgraduate) are not modelled in the BracketMath engines. Plan 2 repayments at 9% above £27,295 add roughly 9p of marginal cost to each £1 of taxable income above the threshold. Add this to the marginal rate quoted on this page if you have an outstanding student loan.

What if I have rental income alongside this self-employment?

Add it to the `otherIncome` field of the calculator. Property income is taxed at non-savings, non-dividend rates (so stacks alongside salary in the band schedule). The first £1,000 of rental income can also be sheltered by the separate Property Allowance under FA 2017 s.16.

Methodology

Income tax, National Insurance and Corporation Tax bands taken from HMRC's 2026/27 rates and allowances tables (gov.uk/.../income-tax; corporation-tax). Pension Annual Allowance and taper rules from Finance Act 2004 / 2023. Trading allowance per ITTOIA 2005 s.783A. Voluntary Class 2 figure (£179.40/yr = £3.45/wk × 52) from HMRC voluntary NI guidance.

Style: 2026/27 tax year throughout; figures rounded to whole pounds in the user-facing prose; effective rates computed as (deductions / gross). The voice is methodological — no first person, no claimed credentials, no marketing fluff.

This page is not personalised advice; for advice regulated by the FCA, consult an adviser registered with the Financial Conduct Authority. See the full disclaimer.