Savings Interest Calculator: Compound Growth
See how your savings grow with compound interest. Adjust the compounding frequency, contributions, rate, and time horizon.
The amount you already have saved
How much you plan to add each month (set to $0 for a lump sum)
Your account's annual rate, before compounding
How often interest is calculated and added to your balance
How long you plan to leave the money growing
Final Balance
$36,904.12
Interest Earned
$7,904.12
Total You Put In
$29,000
Share of Balance From Interest
21.42%
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How compound interest works
Compound interest means you earn interest on your interest. Each period, the bank multiplies your balance by a small fraction of the annual rate and adds it to your balance — so the next period's interest is calculated on a slightly bigger number.
The formula
A = P(1 + r/n)^(nt)
- P — your starting balance
- r — the annual interest rate (as a decimal, so 4% = 0.04)
- n — compounding periods per year (1 annually, 12 monthly, 365 daily)
- t — number of years
A worked example
Start with $5,000 in a high-interest savings account at 4%, compounded monthly, and add $200 every month. After 5 years: your deposits total $17,000, and the balance grows to roughly $19,365 — about $2,365 of that is interest you didn't deposit. Leave it for 10 years instead and the balance reaches about $36,904, with $7,904 from interest. The second five years earns more interest than the first — that's compounding at work.
Savings interest in Canada: what to know
Interest income is taxable
In a regular savings account, every dollar of interest is added to your taxable income for the year — it's taxed at your marginal rate, just like employment income. Your bank issues a T5 slip once you earn more than $50 of interest in a year. The estimate above doesn't account for tax, so your after-tax growth in a non-registered account will be lower.
TFSA vs. non-registered
Inside a Tax-Free Savings Account, interest is completely tax-free — no T5, nothing to report, no tax on withdrawal. If you have unused TFSA room, holding your savings there instead of a taxable account keeps 100% of the interest. See our RRSP vs. TFSA calculator for a side-by-side comparison.
What's a realistic rate?
Savings rates in Canada move with the Bank of Canada's policy rate and change often, so we don't print a number here that could be stale next month. To check what's realistic right now, see the Bank of Canada's current rates or compare live high-interest savings offers on Ratehub . Online-only banks typically pay noticeably more than the big five's standard accounts.