All Calculators
Every CalcKits calculator in one place — free, no sign-up, and each one shows the working behind the answer. Pick a category below, or jump straight to a tool.
Finance
Money maths: what you pay, what you save, and what it grows into.
- Mortgage Calculator — monthly payment, extra payments, and payoff time.
- Compound Interest Calculator — how savings grow when interest earns interest.
- Loan Calculator — monthly payments and total interest on any loan.
- Retirement Calculator — what your savings could be worth when you stop working.
- Simple Interest Calculator — interest on a flat amount, no compounding.
- Savings Goal Calculator — the monthly deposit that hits your target.
- Discount Calculator — sale prices and what you actually save.
- Sales Tax Calculator — tax and total on any purchase.
Health
Body numbers, explained plainly — no judgement, just the maths.
- BMI Calculator — body mass index from height and weight.
- Calorie Calculator — daily calories for loss, maintenance, or gain.
- Body Fat Calculator — body fat percentage from simple measurements.
- Water Intake Calculator — how much water you actually need a day.
- Pregnancy Due Date Calculator — due date and key dates from your last period.
- Ideal Weight Calculator — healthy weight range for your height.
- BMR Calculator — calories your body burns at rest.
Math
Everyday arithmetic, solved step by step.
- Percentage Calculator — percentages, increases, decreases, and change.
- Fraction Calculator — add, subtract, multiply, and divide fractions.
- Average Calculator — mean, median, mode, and range.
- Ratio Calculator — simplify ratios and split amounts fairly.
- GPA Calculator — weighted GPA on a 4.0 scale.
- Unit Converter — length, weight, and temperature.
- Area Calculator — area of rectangles, circles, triangles, and more.
Everyday
The small sums that come up in daily life, answered in seconds.
- Age Calculator — exact age in years, months, and days.
- Tip Calculator — tip, tax, total, and each person’s share.
- Fuel Cost Calculator — what a trip will cost in fuel.
- Days Between Dates Calculator — days between any two dates.
- Date Calculator — add or subtract days, weeks, or months from any date.
- Time Duration Calculator — hours between two times, including overnight.
- Speed Calculator — average speed and running pace.
- Cooking Converter — cups, tablespoons, ml, and grams.