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Frequently Asked Questions

Are these calculators free to use?

Yes — every calculator on Instant-Calculator.com is completely free. No account, subscription, or payment is ever required. Results are instant and work on any device. We support the site through advertising so that the tools themselves always remain free.

How accurate is the mortgage calculator?

Our mortgage calculator uses the standard amortization formula and accounts for principal, interest, property tax, home insurance, and PMI. For Canadian users it applies the mandatory semi-annual compounding rule under the Interest Act of Canada — the same convention used by major Canadian banks — and supports CMHC insurance, accelerated bi-weekly payments, and renewable interest terms. Results match major bank calculator outputs.

Does the mortgage calculator work for Canadian mortgages?

Yes. Select Canada using the country toggle at the top of any page. The calculator automatically switches to semi-annual compounding, shows CMHC mortgage default insurance premiums, supports amortization periods up to 30 years, and includes payment frequencies such as accelerated bi-weekly — one of the most effective ways Canadian borrowers shorten their amortization and save interest.

What is the difference between simple and compound interest?

Simple interest is calculated only on the original principal: I = P × r × t. Compound interest is calculated on both the principal and previously accumulated interest, so balances grow exponentially over time. For example, $10,000 at 5% simple interest for 10 years earns $5,000 in interest. At 5% compounded annually, the same balance grows to $16,289 — earning $6,289. Compounding frequency also matters: monthly compounding grows slightly more than annual compounding at the same rate. Use our interest calculator to compare any combination.

How do I calculate compound interest?

Use our interest calculator. Enter your principal, annual rate, compounding frequency, and term. The formula is A = P × (1 + r/n)^(n×t), where P is principal, r is the annual rate, n is compounding periods per year, and t is years. The calculator also shows a year-by-year breakdown and chart so you can see how your balance grows over time.

What BMI is considered healthy?

The WHO classifies 18.5–24.9 as normal weight, below 18.5 as underweight, 25–29.9 as overweight, and 30 or above as obese. Our BMI calculator shows your score, category, and the healthy weight range for your height. Note that BMI is a screening tool, not a diagnostic measure — factors like muscle mass and bone density are not captured by BMI alone.

What is TDEE and how is it calculated?

TDEE stands for Total Daily Energy Expenditure — the total number of calories your body burns in a day, including physical activity. It is calculated by first finding your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor equation — the calories your body needs at complete rest — and then multiplying by an activity factor based on your exercise level. A sedentary person might need 1,800 calories per day while a very active person of the same size might need 2,800 or more. Our calorie calculator does all of this automatically.

How much money do I need to retire?

A common rule of thumb is the 4% rule: save 25 times your expected annual expenses. For $50,000/year in spending that means $1,250,000 saved. For $80,000/year, it means $2,000,000. This assumes a balanced portfolio that historically supports a 4% annual withdrawal without running out over 30 years. Use our retirement calculator to personalise this based on your current age, existing savings, monthly contributions, expected return, and planned retirement age.

How do I find out how much house I can afford?

A common guideline is that your total monthly housing costs — mortgage payment, property taxes, and insurance — should not exceed 28% of your gross monthly income. All debt payments combined should stay under 36–43%. Use the mortgage calculator to test different home prices and loan terms until the monthly payment fits within those limits. For example, on a $6,000/month gross income, a target housing payment of around $1,680 is a reasonable starting point. Working backwards from that number is often easier than starting from a purchase price.

Is my data private when using these calculators?

Yes. All calculations run entirely within your browser. No financial figures, health metrics, or personal information you enter into any calculator is sent to a server, stored in a database, or shared with any third party. We collect standard anonymous analytics data — such as which pages are visited — to improve the site, but never the inputs you type. You can verify this by disconnecting from the internet after the page loads; the calculators will continue to work normally.