Profit Margin Calculator for UK Businesses

Last reviewed: 17 May 2026

Calculate UK gross, operating, and net profit margins with HMRC corporation tax built in. Free, browser-based, sterling-ready for small businesses.

Profit margin equals profit divided by revenue. Gross margin uses cost of goods sold; net margin subtracts all costs and tax. A healthy small-business net margin is ten percent.

A UK profit margin calculator returns gross, operating, and net margins after VAT (20%), Corporation Tax (25% main / 19% small profits, with marginal relief between £50k-£250k), and employer NI (15% above £5,000). Enter VAT-exclusive revenue. HMRC's CT600 guidance and VAT Notice 700 are the authoritative references.

Margin and markup get confused constantly in UK SME finance — a 50% markup is only a 33.3% margin, and that 16.7 percentage-point gap is the difference between a healthy business and one quietly losing money on every unit sold. This calculator separates the three margin layers (gross, operating, net) using your VAT-exclusive revenue figure — the HMRC standard for accounts filed with Companies House — so you're not inflating the top line by 20% of VAT you collect on HMRC's behalf.

Costs go into two buckets. Cost of goods sold (COGS) is everything that scales with the unit sold: supplier invoices, import duty since the EU-UK Trade and Cooperation Agreement changes, freight, payment processing (Stripe, GoCardless, Worldpay), and packaging. Operating overheads are rent, payroll including 15% employer National Insurance above the £5,000 secondary threshold, software, professional fees, and marketing.

Realistic UK net-margin benchmarks (HMRC sector ratios + FAME small-company data): - Professional services: 12-25% - Trades and construction: 4-8% - Ecommerce: 5-12% depending on category and ad spend - Hospitality: 2-7% (London rents compress this further) - SaaS post-scale: 20%+ once customer acquisition cost normalises

If gross margin lands under 30%, you're in a high-volume model where price discipline and tight inventory turns are the strategic levers — not cost-cutting. If gross is above 60%, customer acquisition cost is the binding constraint.

The calculator also flags when your Corporation Tax estimate (using the marginal relief formula between £50,000 and £250,000 profit) suggests pulling forward capex or pension contributions before year-end. For the underlying rules, HMRC's CT600 guidance, VAT Notice 700, and the Employer Helpbook on gov.uk are the authoritative sources.

Worked example

UK retail example — VAT-exclusive figures.

A Manchester homewares shop records £600,000 of VAT-exclusive revenue. Cost of goods sold (supplier invoices, import duty, freight, packaging) is £360,000. Operating expenses — rent, salaries including 15% employer NI, software, and marketing — come to £150,000. Corporation Tax is set at 25%.

Gross margin: (600,000 − 360,000) ÷ 600,000 = 40%, a healthy product-business figure.
Operating profit: 240,000 − 150,000 = £90,000, an operating margin of 15%.
Net profit after 25% CT: 90,000 × 0.75 = £67,500, a net margin of 11.25%.

That 11.25% net sits comfortably inside the HMRC small-company retail range. The gap between 40% gross and 11.25% net shows overhead and tax doing most of the damage — the lever here is OpEx control, not deeper COGS cuts.

See the formula

See parent calculator at /profit-margin-calculator for the full formula reference.

Frequently Asked Questions

Should I enter VAT-inclusive or VAT-exclusive revenue?

Enter VAT-exclusive revenue. The 20% VAT you charge is collected on HMRC's behalf, not income, so including it overstates your top line and inflates every margin. VAT-exclusive turnover is the figure that ties to your CT600 and the accounts filed at Companies House, so the calculator's gross, operating, and net margins line up with what you actually report.

Which UK Corporation Tax rate should I put in the Tax Rate field?

Use 19% if your profit is under £50,000 (small profits rate) and 25% above £250,000 (main rate). Between those thresholds your effective rate sits in the 19-25% band because of marginal relief, so estimate the blended figure rather than picking one extreme. The field is editable for exactly this reason — override the regional default to match your own effective rate.

Does this calculator account for employer National Insurance?

Not as a separate field. Employer NI (15% above the £5,000 secondary threshold) is part of your payroll cost, so fold it into Operating Expenses alongside salaries, rent, and software. Once it sits in OpEx it correctly pulls down your operating and net margin, which is where wage-related costs belong in the gross-to-net waterfall.

My UK gross margin is under 30% — is that a problem?

Not necessarily. Under 30% gross signals a high-volume model where price discipline and tight inventory turns are the strategic levers, not blanket cost-cutting. Trades and construction routinely run 4-8% net on thin gross. Compare your net margin to the HMRC sector benchmark for your industry rather than judging the gross figure in isolation.

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Methodology & sources

Rates last verified: May 2026

Read the full methodology →

Tax rate defaults reflect each region's headline corporate tax rate. Override the rate if your effective rate differs (e.g. UK small profits rate, US state tax additions).

Primary sources

Rates are reviewed annually or when a region changes its headline rate. If you spot one that's out of date, email [email protected].

For information only. This calculator does not constitute financial, accounting, or tax advice. Consult a qualified professional before making business decisions.

Try these scenarios

Pre-filled examples — click any chip to load the inputs and result.

How to calculate profit margin

Pick your regionToggle USA, UK, or South Africa to load the right currency symbol and pre-fill the corporate tax rate.
Enter total revenueType your sales or revenue for the period in the Revenue field.
Enter cost of goods sold (COGS)Add the direct costs to produce or buy what you sold.
Add operating expenses (optional)Add rent, salaries, marketing, and overhead to unlock the operating margin result.
Read your margin tierGross, operating, and net margin display with color-coded interpretation — green is healthy, amber is caution, red needs action.

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Written by

James Blanckenberg

Founder, BusCalcTools

Founder of BusCalcTools and FinnCalc. Builds practical financial calculators for small business owners and freelancers across the US, UK, and South Africa.

Editorial review by: James Blanckenberg, Founder & Editor

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