Business Budget Calculator

A business budget is not a household budget

Two things make this a different exercise from planning personal spending. Revenue is uncertain rather than a fixed pay cheque, so the plan has to survive a bad month rather than merely allocate a known amount. And costs split usefully into fixed and variable rather than into needs and wants, because that split is what tells you whether growth helps or hurts you.

Fixed costs (rent, salaries, software, insurance, loan payments) are owed whether you sell anything or not. Variable costs move with volume: materials, payment processing, shipping, contractor time, commissions. Knowing which is which gives you two numbers a household budget never needs.

The two numbers to pull out of your expense list

Contribution margin is revenue less variable costs, as a percentage. It is the share of every incoming dollar that survives to pay for the fixed base. If your contribution margin is 40%, every dollar of new sales contributes 40 cents toward covering fixed costs, and only after those are fully covered does anything become profit.

Break-even revenue follows directly: total fixed costs divided by the contribution margin. Fixed costs of $12,000 a month at a 40% contribution margin means you need $30,000 in monthly revenue to break even. That single figure is more actionable than a surplus or deficit total, because it is a target you can put in front of a sales team. The break-even calculator works it through, and the profit margin calculator separates gross from net margin.

The reason the split matters strategically: a business with high fixed costs and a high contribution margin scales beautifully past break-even and dies fast below it. A business that is mostly variable cost is far more resilient in a downturn and never gets the same leverage on the way up. Neither is better, but they need different amounts of cash in reserve.

What a monthly surplus does not tell you

A budget that shows a healthy monthly surplus can still run a business out of money, because a budget is not a cash flow forecast. Four gaps to close:

• Timing. Revenue invoiced in March at net-30 arrives in April, or in June if the client is slow. Your rent and payroll do not wait. Most small businesses that fail while profitable fail here. Model it in the cash flow calculator.
• Sales tax is not revenue. The GST/HST on your invoices is money you are holding for the CRA. Budgeting it as income means the remittance date arrives and the money is spent. Which rate you collect depends on the customer’s province, not yours: see which sales tax to charge.
• Payroll remittances are not optional. Income tax, CPP and EI withheld from staff must be remitted to the CRA on schedule, and directors can be held personally liable for failures. Treat remittances as a separate, untouchable obligation rather than a line in the general expense pool.
• Staff cost more than salary. CPP and EI employer shares, workers’ compensation premiums, provincial employer health tax and vacation pay all land on the employer. Budgeting a hire at their salary understates the commitment: the employee cost calculator gives the loaded figure.

Building a budget that survives contact with reality

Three habits that separate a useful budget from a spreadsheet nobody reopens. Budget revenue conservatively and costs generously: if you are going to be wrong, be wrong in the direction that leaves you solvent. Build the seasonality in explicitly rather than dividing an annual figure by twelve, because almost no business earns evenly and the flat version hides exactly the months that will hurt. And re-forecast monthly against actuals rather than setting the budget once a year; the value is in the variance, which tells you which assumption was wrong while it is still cheap to fix.

Planning personal money rather than a business? The personal budget calculator uses the 50/30/20 framework on take-home pay. Sizing a business from scratch? Start with startup costs to establish the capital needed and the runway it buys.