High-Interest Savings Calculator Canada

What the high-interest savings calculator does

Many Canadians keep an emergency fund or short-term savings in a high-interest savings account, which pays a competitive rate with no risk to the balance. This calculator compounds your starting amount and monthly deposits at the rate you enter, reports the final balance, separates the interest from your own money, and shows what tax leaves behind. Interest in an ordinary account is taxed every year, so the headline rate overstates what you keep.

How the growth is calculated

• The annual rate is divided by twelve for a monthly rate.
• Your starting balance grows for the full number of months.
• Each monthly deposit grows for the months that remain, so early deposits earn more than later ones.

The final balance minus everything you put in is the interest earned, and your marginal tax rate applied to that interest gives the tax and the after-tax result.

A worked example

You start with $10,000 and add $200 a month for five years at 4%. The balance grows to about $25,469.76. You deposited $22,000, so the interest is about $3,469.76. At a 30% marginal rate, about $1,040.93 goes to tax, leaving $24,428.83. Held in a TFSA, the same account would keep the full $25,469.76.

Why tax treatment changes the answer

Two accounts paying the same rate can deliver different results. In a plain account, interest is added to your income and taxed each year at your marginal rate. In a TFSA, it compounds untouched. Enter your real marginal rate for a taxable account, or zero for a TFSA. If you have unused TFSA room, holding the savings there usually wins.

Combined federal and provincial marginal rates differ across Canada, so the same interest leaves different amounts in different provinces. The calculator does not store provincial rates; enter the rate that applies to you, and update it if your income or province changes.

When to use it

• Shopping for an account, to turn a quoted rate into dollars.
• Building an emergency fund, to see how monthly deposits add up.
• Comparing a taxable account with a TFSA by changing the tax rate.
• Working out how long a savings goal will take.

Common mistakes to avoid

• Entering a promotional rate as if it lasted the whole period. Many high-interest accounts pay an elevated rate for only three to six months, then drop to a lower ongoing rate.
• Setting the tax rate to zero for an account that is not inside a TFSA. Interest in a plain account is reported on a T5 slip and goes on line 12100 of your return.
• Forgetting that TFSA room is limited. You can check your room in CRA My Account.
• Treating the projection as a guarantee. Savings rates move with the Bank of Canada’s policy rate.

Things to keep in mind

The projection assumes the rate holds for the whole period and that deposits arrive steadily each month. The tax figure uses one flat marginal rate, while your actual rate can change from year to year. Run the same balance at two rates to value shopping around, and over two horizons to see what time adds. Keep a note of the rate and date you used so you can update the estimate later.

This information is general in nature and is not financial advice.

About This High Interest Savings Calculator

Use this high interest savings calculator to get an instant estimate based on the figures you enter. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.