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🇬🇧 UK£100,000Self Assessment

Self Assessment on £100,000 (UK 2026)

Self Assessment on £100,000 trading profit (UK). rUK, no expenses: Income Tax £27,432.00, Class 4 £3,256.60, total £30,688.60. With £1,000 trading allowance: total £30,268.60. Scotland (no expenses): total £33,988.65.

By Sammy S. · Founder · AuthorUpdated for 2026

£30,688.60
rUK total
£30,268.60
Allowance
£33,988.65
Scotland

Calculate from £100,000

Pre-filled with £100,000 turnover. Adjust expenses, region, or other income.

Your inputs

Turnover, expenses, region

£

Total trading income before expenses

Enter allowable business expenses below.

£
£

e.g. employment — affects Income Tax bands / PA taper only

Total tax + NI

rUK

£30,688.60

Effective 30.69% of trading profit £100,000

Trading profit£100,000.00
Income Tax£27,432.00
Class 4 NI£3,256.60
Class 2 cashTreated as paid
Take-home from trading£69,311.40
POA each (simplified 50%)£15,344.30
20% band£7,540.00
40% band£19,892.00

If payments on account apply, each instalment is usually half of last year’s Self Assessment bill (Income Tax + Class 4), due 31 January and 31 July. Planning estimate from this year’s figures: about £15,344.30 each. Confirm with HMRC.

Class 2 treated as paid (profits ≥ £7,105).

Sole traders & freelancers
Estimate tax and Class 4 before Self Assessment deadlines and set money aside.
Side-hustle earners
Model turnover with the £1,000 trading allowance when expenses are small.
Advisers (quick check)
Band-level sanity check against published HMRC rates — not a filing substitute.

UK Self Assessment for sole traders is estimated for tax year 2026/27: trading profit after expenses or the £1,000 trading allowance, then Income Tax (rUK or Scotland) plus Class 2/4 National Insurance. Income tax uses the same HMRC bands as our UK salary engine; NI uses the self-employed Class 2/4 engine.

Worked example — £100,000

Trading profit£100,000.00
Income Tax£27,432.00
Class 4 NI£3,256.60
Total tax + NI£30,688.60
Take-home from trading£69,311.40

£100,000 profits → Income Tax £27,432.00 + NI £3,256.60 = £30,688.60

Formulas

  • Trading profit
    Profit = Turnover − expenses OR Turnover − min(£1,000, Turnover) if claiming the trading allowance
  • Income Tax
    Tax on (trading profit + other income) after Personal Allowance (standard £12,570, taper above £100,000)
  • Class 4 NI
    6% between LPL and UPL; 2% above UPL — on trading profit only
  • Payments on account (simplified)
    Each instalment ≈ 50% of (Income Tax + Class 4) for planning — confirm HMRC rules
  1. Work out taxable trading profit — Use allowable expenses, or claim the £1,000 trading allowance instead (not both).
  2. Apply Income Tax bands — Other taxable income is added for banding and PA taper only.
  3. Add Class 2/4 NI — Same self-employed NI rules as the National Insurance calculator.
Personal Allowance£12,570gov.uk 2026/27
Trading allowance£1,000gov.uk trading allowance
Basic-rate band (rUK)20% to £50,270gov.uk Income Tax rates
Class 4 main / additional6% / 2%Self-employed NI

Key takeaways — £100,000

  • £100,000 rUK, £0 expenses → £30,688.60 tax+NI.
  • £100,000 with trading allowance → £30,268.60.
  • £100,000 Scotland → £33,988.65 (Income Tax £30,732.05).
  • Effective rate on trading profit (rUK, no expenses): 30.69%.
  • Add real expenses in the calculator for a closer estimate.

Self Assessment on £100,000

This page estimates UK Self Assessment for a sole trader with £100,000 turnover (modelled as taxable profit when expenses are £0).

rUK Income Tax £27,432.00 + Class 4 £3,256.60 = £30,688.60 (take-home from trading £69,311.40).

Claiming the trading allowance on £100,000 turnover reduces profit by £1,000 and changes the total to £30,268.60.

Estimates on £100,000

rUK total
£30,688.60

Tax £27,432.00 · Class 4 £3,256.60

Trading allowance
£30,268.60

Profit £99,000

Scotland
£33,988.65

Tax £30,732.05

rUK estimate for £100,000

Personal Allowance £12,570; taxable income £87,430.00; Income Tax £27,432.00.

Class 4 £3,256.60; total £30,688.60; take-home from trading £69,311.40.

Trading allowance on £100,000

Claiming the £1,000 allowance instead of expenses gives trading profit £99,000.00 and total tax+NI £30,268.60.

Scotland estimate for £100,000

Scottish Income Tax bands produce £30,732.05 tax on this amount (Class 4 still £3,256.60).

Checklist for £100,000

  • Budget about £30,688.60 if £100,000 is taxable profit with no expenses (rUK).
  • Decide expenses vs trading allowance.
  • Set aside payments on account if required.
  • Confirm Scotland vs rUK tax residency for Income Tax.
  • Keep records for Self Assessment.

Other amounts

Calculator hub£20,000£30,000£40,000£50,000£60,000£80,000

Self Assessment on £100,000 — FAQ

rUK with no expenses: Income Tax £27,432.00 + Class 4 £3,256.60 = £30,688.60.

Taxable profit becomes £99,000.00; total tax+NI £30,268.60.

Scotland Income Tax £30,732.05 + Class 4 £3,256.60 = £33,988.65.

rUK, no expenses: about £69,311.40 after Income Tax and Class 4 (modelled).

A simplified estimate is about £15,344.30 twice a year (50% of Income Tax + Class 4). HMRC rules may differ.

No. Figures use published gov.uk rates for modelling only.

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