What is gross profit margin?

Gross profit margin is your gross profit divided by revenue, shown as a percentage. It tells you how much of every £1 of sales is left after the direct costs of delivering your product or service.

How do you calculate break-even turnover?

Break-even turnover is your fixed overheads divided by your gross profit margin (as a decimal). It's the level of revenue at which your business covers all its costs and makes neither a profit nor a loss.

What are debtor days?

Debtor days estimate the average number of days your customers take to pay you: trade debtors divided by revenue, multiplied by the number of days in the period. Lower debtor days means cash reaches your bank faster.

Cash runway estimates how many months your available cash would cover your operating costs at current levels. It's a simple gauge of financial resilience if income paused.

What is customer concentration?

Customer concentration is the share of your total revenue that comes from your single largest customer. The higher it is, the more exposed your business is if that customer leaves.

Interactive tool

The CASS Key Business Numbers Calculator

Know your numbers. Understand what they're telling you.

Most business owners don't need hundreds of reports. They need a handful of numbers they understand, review regularly and use to make better decisions. Enter a few figures from your business and we'll calculate some of the key numbers every business owner should understand.

This calculator is the interactive companion to Workbook 2 — The 10 Numbers Every Business Owner Should Know.

Your figures

Financial period

VAT basis

Profit & Loss

Turnover / RevenueTotal sales income for the period, before costs.

Direct Costs / Cost of SalesCosts directly associated with supplying your products or services (including any direct payroll). Do not include general overheads such as office rent or accountancy fees.

Direct payroll (within cost of sales)The wage cost of the people who directly deliver your products or services. This sits inside your Direct Costs above.

Total OverheadsYour fixed running costs — rent, software, insurance, admin salaries, etc. (including overhead payroll).

Overhead payroll (within overheads)The wage cost of management and admin staff — not tied to delivering a specific sale. This sits inside your Total Overheads above.

Net ProfitProfit after all costs (direct costs and overheads). Enter a negative figure if you made a loss.

Cash & Balance Sheet

Cash in BankMoney currently available across your business bank accounts.

Trade Debtors (unpaid customer invoices)The total your customers currently owe you in outstanding invoices.

Trade Creditors (unpaid supplier bills)The total you currently owe your suppliers.

Current AssetsAssets you expect to turn into cash within 12 months — cash, debtors, stock.

Current LiabilitiesAmounts due within 12 months — creditors, short-term loans, tax due.

Monthly Recurring CostsYour regular fixed monthly commitments (subscriptions, rent, salaries).

Customers

Number of CustomersRoughly how many customers generated the revenue above.

Revenue from Largest CustomerHow much revenue came from your single biggest customer.

Recurring RevenueRevenue you can reasonably rely on repeating (retainers, subscriptions, contracts).

People

Number of Employees / FTEAverage full-time-equivalent staff over the period.

Last Period (for growth)

Previous Period RevenueYour revenue for the previous comparable period.

Previous Period ProfitYour net profit for the previous comparable period.

Your Business Numbers Dashboard

Start entering your figures on the left and your key numbers will appear here instantly — with plain-English explanations of what each one means.

Go further

Your numbers tell you what's happening financially. These tools help you understand the wider picture.

Business Growth Health Check

Your numbers tell you what's happening financially. This checks whether the wider business is healthy.

Growth Readiness Assessment

See whether your business is ready for its next stage of growth.

Owner Independence Assessment

Find out how much the business depends on you personally.

You know your numbers. Now understand what they're telling you.

Calculating the numbers is the first step. The real value comes from understanding why they are changing, what they mean for your business and what you should do next.

Let's Talk About My Numbers Download The 10 Numbers Every Business Owner Should Know Workbook

This calculator is designed to help you understand common business metrics and explore potential scenarios. Results are based entirely on the figures you enter and should not be treated as accounting, tax, investment or financial advice. Individual businesses and industries differ, so results should always be considered in the context of your own circumstances.