Calculator Hub

20 free calculators, each with a worked example and FAQs. Everything runs in your browser — no sign-up, no uploads.

All calculators

Biweekly Mortgage Payoff CalculatorSee how paying half your mortgage every two weeks (26 half-payments a year) cuts years off your loan and saves interest, versus standard monthly payments. Extra Mortgage Payment CalculatorSee exactly how much interest an extra monthly payment saves and how many months it cuts off your mortgage, with a standard-payment comparison. Mortgage Affordability CalculatorEstimate the maximum house price you can afford from your income, debts, down payment and rate, using the 28/36 debt-to-income rule lenders use. Compound Interest CalculatorGrow a lump sum plus monthly contributions at a fixed annual rate with monthly compounding, and see total invested versus interest earned. SIP CalculatorEstimate how a fixed monthly investment (SIP) grows at an expected annual return, with total invested versus returns shown separately. Step-Up SIP CalculatorSee how raising your monthly SIP by a fixed percentage each year grows your investment faster than a flat SIP, with invested versus returns shown. Debt Payoff Calculator — Snowball vs AvalancheCompare the snowball method (smallest balance first) with the avalanche method (highest rate first) for your debts, with months to debt-free and total interest for each. Credit Card Payoff CalculatorFind how long a fixed monthly payment takes to clear a credit card balance at a given APR, and how much interest you will pay along the way. Salary to Hourly CalculatorConvert an annual salary to an hourly, weekly, biweekly and monthly rate, with adjustable weeks per year and hours per week. Overtime Pay CalculatorCalculate weekly pay with overtime at time and a half: regular hours at the base rate, hours over 40 at 1.5 times the rate. Tip & Split Bill CalculatorWork out the tip, the total bill and what each person pays, for any bill, tip percentage and group size. Discount & Sales Tax CalculatorTwo tools in one: work out a sale price after a percent-off discount, or add sales tax to a price — with savings and totals shown. BMI Calculator for WomenCalculate body mass index for women from weight and height, with the WHO category and the healthy weight range for your height. TDEE CalculatorEstimate daily calorie needs from the Mifflin-St Jeor equation plus an activity multiplier, with targets for losing, maintaining or gaining weight. Body Fat Calculator — US Navy MethodEstimate body fat percentage with the classic US Navy circumference method: height plus neck and waist for men, plus hips for women. Water Intake CalculatorEstimate daily water needs from body weight, exercise and climate, in litres, glasses and ounces. Pregnancy Due Date CalculatorEstimate a due date from the first day of the last menstrual period using Naegele's rule, plus current week, trimester and conception estimate. Exact Age CalculatorWork out an exact age in years, months and days between any birth date and any reference date, plus total days lived and the next birthday. Working Days CalculatorCount Monday-to-Friday working days between two dates, inclusive, with the calendar-day total and weekends excluded shown. Weighted GPA CalculatorCalculate weighted GPA on a 4.0 scale with honors (+0.5) and AP/IB (+1.0) weighting, plus the unweighted GPA for comparison.