🇨🇦 Canada Interest Calculator

Model simple or compound growth in CAD using your own HISA or GIC rate assumption.

Final amount

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Simple interest—

Simple Final amount—

Compound interest—

Total contributions—

Estimated after-tax interest—

Estimated real purchasing power—

This calculator uses your assumptions, not current product rates. Tax and deposit coverage depend on the account and institution. Bank of Canada · CDIC HISA · CRA interest income

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Calculator inputs

Starting balance is the CAD amount already on deposit. Nominal annual rate is the rate assumption you want to test, not a rate fetched from a bank. Time period is entered in years. Monthly contribution is the amount the model adds after each month's interest calculation. Compounding frequency tells the calculator to treat the annual rate as compounded monthly, quarterly, or annually. Inflation assumption is a constant annual rate used only to restate the after-tax balance in today's purchasing power. Marginal tax assumption is a single percentage applied to the interest at the end of the projection. Calculation type controls whether the page shows simple interest, compound interest, or both. Use Compound for a deposit whose credited interest stays in the account. Use Simple only for a comparison in which earned interest does not itself earn interest. When Both is selected, the large Final amount and the tax and inflation outputs follow the compound result, while separate rows show both interest methods.

Calculation formulas

Let P be the starting balance, r the entered annual rate as a decimal, f the selected compounding periods per year, m the number of months, and C the month-end contribution. The compound path first calculates a monthly growth rate as (1 + r / f) raised to the power f / 12, minus 1. Each month it multiplies the existing balance by one plus that monthly rate, then adds C. This conversion makes twelve monthly steps reproduce the annual result implied by the selected nominal rate and frequency. The simple path calculates interest as P × r × m / 12 + C × r × m × (m - 1) / 24. The second term gives earlier month-end contributions more time and the final contribution no interest. In both paths, total contributions equal P + C × m. The calculator converts years to months by multiplying by twelve and rounding to the nearest whole month. Negative principal, rate, time, or contribution entries are treated as zero.

Worked CAD example

Enter a CAD 10,000 starting balance, a 4% nominal annual rate, 5 years, a CAD 100 monthly contribution, monthly compounding, 2% inflation, and a 30% marginal tax assumption. The JavaScript runs 60 monthly steps and counts CAD 16,000 of total contributions. Its compound path produces CAD 18,839.86, so compound interest is CAD 2,839.86. Applying the entered tax percentage leaves CAD 1,987.90 of estimated after-tax interest and an after-tax balance of CAD 17,987.90. Discounting that balance for five years at the entered inflation assumption gives CAD 16,292.20 of estimated real purchasing power. Under the Simple path, the same entries produce CAD 2,590.00 of interest and a CAD 18,590.00 final amount. Estimated after-tax interest is CAD 1,813.00, and estimated real purchasing power is CAD 16,133.78. These are calculator outputs from the stated inputs, not forecasts of a HISA or GIC offer.

Result meanings

Final amount is the gross ending balance before the tax and inflation adjustments. If you choose Both or Compound, it is the compound balance. If you choose Simple, it is the simple balance. Simple interest and Simple final amount disappear in Compound mode; Compound interest disappears in Simple mode. Total contributions includes the starting balance and every modelled month-end deposit, so it is not interest earned. Estimated after-tax interest is calculated interest multiplied by one minus your tax percentage. The calculator does not display the full after-tax balance, although it uses that balance for the purchasing-power calculation. Estimated real purchasing power is total contributions plus after-tax interest, divided by the cumulative effect of your constant inflation assumption. Currency results are displayed to two decimal places, but the calculation keeps unrounded values internally. The bar chart appears only in Both mode and compares gross simple interest with gross compound interest. It does not compare final balances, taxes, or purchasing power.

HISA and GIC terms

A Canadian high-interest savings account, or HISA, usually keeps deposits accessible while its posted rate can change. A guaranteed investment certificate, or GIC, normally applies an agreed rate for a stated term. A non-redeemable GIC can restrict access until maturity, while a cashable or redeemable GIC may permit earlier access under its contract. The calculator does not price that difference in liquidity. It also assumes the same entered rate throughout the full time period. That can suit a fixed-rate GIC held to maturity, but it is only a scenario for a variable-rate HISA. Some GICs are funded with one purchase amount and do not accept monthly additions to the same certificate. For a single GIC, set Monthly contribution to zero. A nonzero contribution can instead represent regular HISA deposits or a simplified series of future GIC purchases, but the tool treats every deposit as if it earns under one shared rate and schedule. It does not create a GIC ladder or track separate maturity dates.

Posted rate details

Match the Nominal annual rate and Compounding frequency entries to the product disclosure. A rate labelled annual does not by itself tell you when interest is calculated, credited, or paid. A HISA may calculate interest from daily balances and credit it monthly. A GIC may compound interest inside the certificate or pay interest out instead, depending on its terms. This calculator has monthly, quarterly, and annual compounding choices only. It has no daily-balance option and assumes credited interest remains in the modelled balance. If GIC interest is paid to another account, the Compound result can overstate the amount remaining in the certificate. Promotional HISA rates also need care. Entering a temporary bonus rate for the whole term assumes that bonus never ends. Run separate scenarios with the ordinary rate and promotional rate, or shorten the period to the offer window. Do not enter both an effective annual yield and a separate compounding setting unless the institution describes the quote that way, because that can count compounding twice.

Deposit protection

The Canada Deposit Insurance Corporation, or CDIC, insures eligible deposits held at each CDIC member institution. Coverage is organized by insured category, so deposits in different categories at the same member can be treated separately. Deposits at different member institutions are also assessed separately. The account label alone is not enough: confirm that the institution is a member, the deposit is eligible, and the ownership category is recorded correctly. A HISA or GIC sold through a financial group may legally be a deposit of a particular member institution, which matters when you total deposits for coverage. CDIC insurance protects eligible deposits if a member fails; it does not guarantee the interest assumption entered here, remove a GIC's redemption conditions, or protect products that are not eligible deposits. Provincially regulated credit unions may use a provincial deposit-protection system instead of CDIC. The Financial Consumer Agency of Canada supervises federally regulated financial institutions for compliance with federal consumer-protection requirements, including complaint-handling rules. A bank must make its complaint process available, while FCAC can explain that process and monitor compliance but does not resolve an individual claim. The calculator does not identify the issuer, ownership category, beneficiary structure, or insurance system, and it does not divide a balance among institutions.

Canadian tax treatment

Interest in a non-registered HISA or GIC is generally income for Canadian tax purposes. A financial institution may issue a T5 information slip, but the reporting obligation can still apply when no slip arrives. For a GIC that runs longer than one reporting period, tax rules may require interest to be reported as it accrues rather than only when cash is paid at maturity. The calculator does not model that timing. It applies your marginal tax assumption once to all calculated interest after the final month. Your actual marginal rate can combine federal and provincial or territorial tax and can change as income changes. Inside a TFSA, interest is generally tax-free, and withdrawals are generally not included in taxable income. Inside an RRSP, interest is not taxed as it accrues, but withdrawals are generally included in income. Setting the tax assumption to zero can model growth inside either plan, but it does not model TFSA contribution room, RRSP deductions, withdrawal tax, overcontributions, or transfers.

Offer comparisons

Use identical starting balance, time, contribution, tax, and inflation entries when comparing two offers, then change only the rate and compounding frequency. That isolates the mathematical effect of the quoted interest terms. Next, account separately for conditions the calculator cannot enter: monthly account fees, minimum-balance rules, transaction charges, a promotional-rate expiry, and GIC early-redemption terms. A slightly higher gross Final amount can be worse if fees consume the difference or if the money is unavailable when you need it. Check whether a GIC pays interest into the certificate or out to another account before relying on compound growth. For a HISA with a changing rate, test more than one entered rate rather than treating the current offer as permanent. Compare Estimated after-tax interest only when the deposits have the same tax treatment. A TFSA result with a zero tax assumption and a non-registered result with a marginal-rate assumption answer different questions. Finally, compare CDIC or provincial coverage by legal issuer and category, not only by the brand shown on an app or statement.

Model limits

This is a fixed-assumption projection, not an account statement or tax calculation. It does not fetch rates, change a HISA rate over time, end a promotional rate, or create separate GIC terms. It ignores leap years and daily balances because every projection uses rounded whole months. Contributions always arrive at month-end, after that month's growth, and cannot vary or stop partway through the term. There are no withdrawals, fees, withholding amounts, minimum balances, or early-redemption adjustments. Compound interest stays in the balance; the model cannot send GIC interest to another account. Tax is deducted once from total interest, so the Compound result does not reflect the smaller base that could result if annual tax were paid from the account. Inflation is one constant annual assumption applied to the estimated after-tax balance, including contributed principal. The tool does not cap the number of months entered. Long projections can magnify small differences in the rate, timing, and frequency assumptions. Read the institution's disclosure and the Canada Revenue Agency rules for the actual deposit before acting on the estimate.

Frequently asked questions

Does this calculator fetch current Canadian HISA or GIC rates?

No. It uses only the Nominal annual rate you enter. Copy the rate and compounding details from the offer you are comparing. If a HISA rate is promotional or variable, run separate scenarios rather than assuming that one rate continues for the entire period.

When does the calculator add each monthly contribution?

It first applies one month of growth to the existing balance and then adds the contribution. The first contribution therefore earns for one month less than the starting balance, and the final contribution earns no interest before the projection ends. There is no beginning-of-month option.

Which result is used for tax and inflation when I choose Both?

Both mode uses the compound result. Estimated after-tax interest is compound interest after the entered tax percentage, and Estimated real purchasing power starts with the compound after-tax balance. The simple rows remain visible for comparison, but they do not drive those two outputs.

Should I enter monthly contributions for a GIC?

Use zero for a single GIC that accepts only the purchase amount at opening. A monthly amount can approximate regular HISA deposits or repeated future GIC purchases, but the calculator applies one rate and one compounding rule to every contribution. It does not track separate certificates or maturities.

How should I model a TFSA or RRSP?

A zero tax assumption can show interest accumulating without current tax inside either registered plan. For a TFSA, the calculator still does not check contribution room. For an RRSP, it omits the contribution deduction and the income tax generally due on withdrawal, so the result is only the inside-plan balance path.

Does CDIC coverage follow the bank brand or the account?

Coverage depends on the eligible deposit, the CDIC member institution that issued it, and its insured category. Related brands can involve different legal issuers, while several products can belong to one issuer. Confirm those details directly because the calculator does not identify institutions or allocate balances among coverage categories.

TRUST & SOURCES

Methodology and official sources

the Canadian interest calculation explains its inputs, assumptions, and calculation scope.

Official status: Reference calculator; it does not make an official determination.
Effective date: 2026-08-07
Last reviewed: 2026-08-07

Method

It applies simple or compound interest from the entered principal, rate, and time to the entered values.

Worked example

CAD 1,000 at 5% for one year gives CAD 50 simple interest.

Limitations

Rates, rules, and individual circumstances can change the result.

Sources

Investment Calculator Bank of Canada · Official source
High Interest Savings Account (HISA) Canada Deposit Insurance Corporation · Official source
Interest and other investment income Canada Revenue Agency · Official source