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Financial forecasting in Canadian business planning is a plan for cash, and the tax bills are the part most owners leave out. Sales, costs and profit are easy to guess. The GST/HST you collect, the payroll money you owe the CRA and the corporate tax due after year end are the lines that decide whether the forecast holds.
What should a small business forecast include?
Start with three numbers you can build from your own records: expected sales by month, the direct cost of those sales and your fixed costs. Then add the amounts that pass through your bank account without being yours. GST/HST collected sits there until the return is due. Payroll deductions held back from staff sit there until the 15th of the next month, or sooner if you remit more often.
That second group is where forecasts break. A bank balance that looks healthy on the 10th may already belong to the CRA.
Take Ontario sales of $50,000 in a month. At 13% HST, that’s $6,500 collected on top, and none of it is yours. If you spend the whole balance on the 10th, the return still has to be paid when it’s due.
How do you build a monthly cash plan?
Keep it to one page. A spreadsheet is plenty.
- List the next twelve months across the top.
- Put expected sales on the first row and the direct cost of those sales under it.
- Add fixed costs: rent, insurance, software, loan payments.
- Add the tax rows from the table below, in the month each one leaves your account.
- Finish with a closing balance for each month and mark any month that dips below zero.
The months that dip are the ones to fix first, whether by moving a purchase or arranging a line of credit before you need it.
How do you forecast profit from a price?
Price drives everything else, so check it first. Say an item costs you $60 and sells for $100. The profit margin calculator shows a 40% gross margin and a 66.7% markup. Forecast on margin. If you plan on 40% and sell $50,000 in a month, you have $20,000 of gross profit to cover rent, wages and the rest.
Mix the two up and it costs you. A 40% markup on that $60 cost gives an $84 price, which is only a 28.6% margin. That’s eleven points short on every single sale.
Which tax figures belong in the forecast?
| Item | What to forecast | When it is due (CRA) |
|---|---|---|
| GST/HST | Tax collected less tax paid on purchases | One month after a monthly or quarterly period, three months after an annual one |
| Payroll remittance | Amounts held back plus your CPP and EI share | 15th of the next month for regular remitters |
| Corporate tax | Tax on taxable income, paid by instalments | Balance two months after year end, or three for some CCPCs |
| Owner’s personal tax | Tax on salary, dividends or business profit | See your own return |
The CRA’s page on when to remit payroll deductions sets out the remitter types. Corporations usually pay instalments through the year, monthly unless they qualify for quarterly. So corporate tax shows up in the forecast as a regular outflow, not a single payment after the year ends.
A worked example with real payroll and tax numbers
Suppose a company in Ontario employs five people at $3,000 gross every two weeks. The payroll remittance calculator says $4,805.16 goes to the CRA each pay period, and the full cost of the payroll is $16,142.07 per period. Across 26 periods, that’s about $419,700 in payroll cost and about $124,900 remitted. Put the second figure in the forecast as cash out, separate from wages.
Now take $300,000 of taxable active business income. The corporate tax calculator gives $35,088 of combined federal and Ontario tax, an average rate of 11.7%. That’s an estimate. Ontario lowered its small business rate in July 2026, and the tool blends the old and new rates by days, which no government publishes. A corporation with another year end will land somewhere else. Use the figure for planning, then replace it with the real number from your accountant’s return.
Where does financial forecasting go wrong?
Three places, mostly. Owners forecast profit and forget that profit isn’t cash, they treat a growing bank balance as spendable without setting aside the tax that sits inside it, and they never update the plan. So it’s wrong by March.
A forecast is also only as good as the records under it. If your books are a month behind, so is your plan. Missing records are a separate problem, and our page on accounting system failures covers it. For a cash shortage that already exists, see cash flow problems in Canadian businesses.
What about growth? There are no growth rates or industry averages here, because none could be confirmed from an official source. Use your own last twelve months. They beat a borrowed benchmark.
How often should you update the forecast?
Monthly, when you close the books. Swap last month’s guess for the real figure, then push the plan one month forward so you always see a full year ahead. It takes twenty minutes once the habit sticks, and it’s the best early warning a small business has.
Where we got these figures
Due dates and remitter rules come from Canada Revenue Agency pages on payroll, GST/HST and corporate tax payments. The payroll and corporate examples are calculator output on 2026 data. Forecasts for 2026 dates that the CRA hasn’t published yet should be rechecked when they appear.
Frequently asked questions
What is a financial forecast for a small business?
It's an estimate of sales, costs and cash for the months ahead, with tax payments included.
Why include GST/HST in a forecast?
Because the tax you collect is owed to the CRA, so it isn't spendable cash.
How often are payroll deductions due?
For regular remitters, by the 15th of the month after you paid staff. Larger employers remit more often.
Do corporations pay tax once a year?
Usually not. Most pay instalments during the year and the balance two or three months after year end.
Should I forecast margin or markup?
Margin. It's profit as a share of the selling price, which is the number that pays your costs.
- Self-employed taxes in Canada: income, CPP and GST
How tax works when you are self-employed in Canada: reporting income and expenses, paying both halves of CPP, instalments and when to register for GST