Free finance calculators that actually do the math.

Personal finance lives or dies on a few core formulas, and most of them are non-obvious. Compound interest turns small monthly contributions into six-figure portfolios — but the variables that drive it (rate, time, contribution frequency) interact in ways that are hard to intuit. The Rule of 72 says your money doubles in 72 ÷ rate years; at 7%, that's about a decade per double. APR vs APY are not the same thing — APR ignores compounding while APY includes it, which is why a 6% APR credit card actually costs you closer to 6.17% per year.

Mortgages add their own quirks. In Canada, the mortgage stress test forces you to qualify at your contract rate plus 2% (or the Bank of Canada qualifying rate, whichever is higher), cutting roughly 20% off your maximum borrowing power. Amortization is front-loaded with interest — on a $300,000 mortgage at 6%, your first payment of $1,932 sends about $1,500 to interest and only $432 to principal. Switching to accelerated bi-weekly payments can save $30,000+ over a 25-year amortization without changing your monthly cash flow much.

Debt payoff has two main strategies: avalanche (highest interest first, mathematically optimal) and snowball (smallest balance first, psychologically motivating). And on the savings side, the 2025 TFSA contribution limit is $7,000 with $102,000+ in cumulative room for someone who has been eligible since 2009; RRSP room is 18% of last year's earned income up to $32,490. These calculators run all of that math for you.