Rates & sources
UK company rates (Corporation Tax, VAT, payroll NI) as published by HMRC and Companies House.
Source: HMRC — Running a business — figures refreshed at the start of each tax year.
When to use this calculator
- Before pricing a job, setting margin targets, or reviewing hiring costs.
- When you want to test sensitivity around volume, VAT, markup, or overhead changes.
- When you need a practical estimate before committing to a budget or proposal.
- When you are modelling break-even volume and want to see how it shifts as overheads or prices change.
- When you are preparing a quote and need to verify that the margin holds after materials, labour, and VAT are accounted for.
A realistic South Africa planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Revenue (R)
50000
Total Costs (R)
R500
After entering these figures, review profit, margin and markup together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Profit
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Margin
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Markup
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator works on the standard gross profit margin formula: (Revenue − Cost of Goods Sold) ÷ Revenue × 100. Enter your sales revenue and the direct costs associated with producing or delivering your product or service. Direct costs typically include raw materials, stock purchased for resale, and any labour directly tied to production. The calculator does not factor in overheads such as rent, insurance, or administrative salaries — those belong in a net profit calculation.
UK businesses should enter VAT-exclusive figures if VAT-registered. Sole traders and limited companies may have different allowable cost definitions under HMRC rules, so consult your accountant when classifying costs for tax purposes. Use this tool for quick decision-making and pricing reviews rather than as a substitute for formal management accounts.
Common mistakes
- !Using optimistic assumptions without testing a more cautious scenario as well.
- !Comparing outputs from different tools without checking that the inputs match.
- !Treating the result as a final quote instead of a planning estimate.
- !Forgetting to include employer National Insurance contributions when modelling the true cost of a new hire.
- !Using revenue figures in place of gross profit when calculating margin percentage, which produces a misleadingly high result.
What to do next
- Try at least one more scenario with a lower price or higher cost so you can see the margin floor.
- Use the related calculators below to cross-check VAT, payroll, or break-even figures from another angle.
- Open one of the linked guides if you need more context before you finalise a quote or budget.
- If the margin is tighter than expected, identify which single input has the biggest impact and focus any negotiation there first.
- Keep a record of the assumptions behind this estimate so you can revisit and update it when costs or volumes change.
Frequently asked
Use arrow keys to navigate items, Enter or Space to expand/collapse.
End-of-article next steps
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