How to Calculate Cash Flow on a Rental Property in Canada

Rental property cash flow is the rent you collect minus everything you pay to run and finance the property: vacancy, operating expenses and mortgage payments. If the number is positive, the building pays for itself and puts money in your account. If it is negative, you top it up from your own pocket every month.

Cash flow is measured before income tax. It counts real cash in and out, so it includes the full mortgage payment, principal as well as interest, even though only the interest is deductible on your tax return. It leaves out appreciation and the equity you build by paying down the loan, because neither reaches your bank account until you sell or refinance.

That makes cash flow the most practical test of a rental: it tells you whether you can afford to hold the property through a bad year, not just whether it looks good on paper.

To calculate cash flow, start with gross rent, subtract vacancy and operating expenses to get net operating income (NOI), then subtract your mortgage payments.

Cash flow = NOI − Annual debt service

1. Gross potential rent: every unit at its rent for 12 months, plus parking, laundry and storage income.
2. Minus vacancy and bad debt = effective gross income (EGI). Use at least 3–5% even if the building is full today.
3. Minus operating expenses: property taxes, insurance, owner-paid utilities, repairs and maintenance, management, snow removal and admin. The result is net operating income.
4. Minus debt service: 12 months of mortgage payments, principal and interest.
5. Minus a capital reserve (recommended) for big replacements that come every 10 to 25 years.

Getting steps 2 and 3 right matters most. Our guide to vacancy and operating expense assumptions covers what to use when the seller’s numbers look too good.

Take an 8-unit building at $1,950,000 with rents of $1,750 per unit, bought with 35% down: a $1,267,500 mortgage at an illustrative 4.9% over 25 years. Canadian fixed rates compound semi-annually, so the payment is $7,299.85 a month.

Operating expenses are taxes $14,000, insurance $9,600, utilities $12,000, repairs $9,600, management $6,720 and snow, landscaping and admin $4,000. After reserves the building clears about $153 per unit per month. On $727,500 of cash invested (down payment plus $45,000 of closing costs), that is a 2.0% cash-on-cash return.

A capital reserve sets aside money each month for large replacements, such as roofs, boilers, windows and appliances, so they don’t wipe out years of cash flow when they arrive. These costs are not operating expenses, so they are not in NOI, but every building has them.

The Canada Revenue Agency draws the same line for tax. A current expense recurs after a short period, such as repainting or fixing a step. A capital expense gives a lasting benefit, such as new siding or a new refrigerator, and is deducted gradually through capital cost allowance. Your cash leaves either way, so plan for both.

There is no official reserve figure. Many investors set aside 3–5% of rent or a fixed amount per unit, and more for older buildings or ones with original mechanicals. Our example uses $50 per unit per month, about 3% of rent. Ask for the roof, boiler and window ages before you buy: a building with all three near the end of their lives needs a bigger reserve, or a lower price.

Calculate cash flow annually, then divide by 12 for a monthly figure, because many costs arrive once or twice a year rather than every month. Property taxes, insurance renewals, snow contracts and heating bills are lumpy. A building can look excellent in a July bank statement and run short in a January one.

Annual figures are also what lenders, appraisers and sellers use. NOI, cap rate and DSCR are all quoted on a 12-month basis, so working annually keeps your numbers comparable with theirs.

Monthly figures are still useful for one thing: judging your cushion. Cash flow per unit per month tells you how much room you have. At $153 per unit, one month of vacancy on a $1,750 unit uses up nearly a year of that unit’s cash flow. Keep several months of operating expenses and mortgage payments in a separate account so the building never has to borrow from you on short notice.

Positive cash flow means the rent covers every cost and leaves a surplus; negative cash flow means you pay the difference out of pocket. The same building can be either, depending on how it is financed.

Borrow 75% of the price instead of 65%, and the 8-unit building’s cash flow falls to $5,965 a year, or $1,165 after reserves: about $12 per unit per month. If the rate were 5.9% instead of 4.9%, payments would rise to $111,245 a year and cash flow would be −$4,205, or −$750 a month after reserves.

A useful check is break-even occupancy: operating expenses plus mortgage payments, divided by gross potential rent. At 65% loan-to-value it is 85% (88% with the reserve), so the building covers its costs before reserves even with one of eight units empty all year. At 75% loan-to-value and 5.9%, it is 99.5% before reserves and 102% after: the building cannot break even fully rented. Some investors accept negative cash flow in exchange for principal paydown and expected appreciation, but that is a bet on the future that needs a cash buffer to survive.

Good cash flow is positive after a realistic vacancy allowance, full operating expenses and a capital reserve, with enough margin to absorb a rate increase at renewal. There is no universal dollar target, because it depends on the price, the rent level and how much you put down.

Three ratios turn cash flow into something you can compare across deals:

• Cash-on-cash return: cash flow ÷ cash invested. See cap rate vs. cash-on-cash return.
• DSCR: NOI ÷ mortgage payments. Conventional lenders want 1.20 or more on most 5+ unit loans, which forces some cash flow into the deal. See what is DSCR.
• Break-even occupancy: below about 85–90% leaves room for a bad year.

Your down payment is the biggest lever on all three. Our guide to down payments on Canadian rental properties explains how much lenders require.

PropStack runs this calculation for every deal you enter. You set the rent, vacancy rate, property management percentage, taxes, insurance and maintenance reserve, and it shows monthly cash flow, cap rate, cash-on-cash return, DSCR and break-even occupancy, using Canadian semi-annual compounding. A 10-year projection shows how cash flow changes as rents grow and the mortgage renews.

Expenses start from regional benchmarks, and you can save scenarios to compare down payments, rates and amortizations side by side. Try it on a listing, no account needed.