Calculators
Browse local math, statistics, finance, health, geometry, date and time calculators, plus random number generation. Clear inputs, formulas and explanations.
Education
- GPA Calculator: Calculate a credit-weighted GPA from course grades and credit hours using grade-point values you can edit.
- Grade Calculator: Calculate the weighted grade on completed assessments and the average score needed across remaining work for a chosen final target.
Construction / Measurement
- Concrete Calculator: Estimate concrete volume for a rectangular slab, footing/block or cylindrical column, with separate dimension units and an optional extra allowance.
- Conversion Calculator: Convert a value between supported units of length, area, volume, mass, temperature, speed or time, with swap and copy controls.
- Square Footage Calculator: Choose a rectangle, square, circle or triangle and enter dimensions in feet to calculate square feet, square meters and square yards.
Developer / Networking
- Subnet Calculator: Calculate an IPv4 network and address range from a dotted-decimal address and CIDR prefix, including mask, wildcard and host-count interpretation.
Math
- Scientific Calculator: Evaluate an arithmetic or scientific expression with parentheses, powers, roots, logarithms and trigonometry in degrees or radians.
- Fraction Calculator: Perform addition, subtraction, multiplication or division on two signed fractions, with simplified and mixed-number results alongside an approximate decimal.
- Standard Deviation Calculator: Enter a numeric dataset to calculate mean, variance and standard deviation, with population and sample results shown separately.
- Triangle Calculator: Solve sides, angles, area and perimeter from three sides, two sides with their included angle, or one side with two angles.
- Random Number Generator: Generate random integers or decimals on a chosen precision grid between your bounds, with quantity, uniqueness and sorting options.
- Percentage Calculator: Calculate percentages, percentage increase, decrease and difference instantly. See clear formulas and examples with local browser calculations.
Date & Time
- Date Calculator: Find the elapsed days between two dates, or add and subtract calendar years, months, weeks and days from a starting date.
- Time Calculator: Add or subtract a duration from a 24-hour clock time, or find the duration between two clocks with an explicit same-day or next-day choice.
- Hours Calculator: Calculate gross shift duration, break time and net hours from start and end clocks, with overnight handling and decimal-hour output.
- Age Calculator: Calculate age in calendar years, months and days. See elapsed months, weeks and days, plus your next birthday, with local browser calculations.
Health & Fitness
- BMI Calculator: Calculate body mass index from height and weight in kilograms and centimeters or pounds, feet and inches. View the result and general adult category.
- Calorie Calculator: Estimate daily maintenance energy from your age, height, weight, equation parameter and activity assumption. See the resting-energy baseline alongside the activity-adjusted estimate.
- Body Fat Calculator: Estimate adult body-fat percentage from height and circumference measurements using historical U.S. Navy equations. The required tape measurements depend on the equation selected.
- BMR Calculator: Estimate resting energy expenditure using the simplified Mifflin–St Jeor equation and your adult age, height, weight and selected equation parameter.
- Ideal Weight Calculator: Compare four height-based reference-weight formulas in kilograms and pounds. The page shows their differences rather than choosing a single personal target.
- Pace Calculator: Solve pace, elapsed time or distance for running and walking, with kilometer and mile equivalents and speed in both units.
Pregnancy
- Pregnancy Calculator: Estimate gestational weeks and days, approximate stage and due date from the first day of the last menstrual period (LMP) and an as-of date.
- Pregnancy Conception Calculator: Explore an approximate conception date from an estimated due date or LMP. This calendar assumption cannot determine the exact day conception occurred.
- Due Date Calculator: Estimate a due date from LMP or a known conception date, then view gestational age and time remaining for your chosen as-of date.
Finance, Pay & Tax
- Retirement Calculator: Use your current age, retirement age, savings, monthly contribution and assumed return to project a balance at retirement.
- Inflation Calculator: Enter an amount, years and your assumed annual inflation rate to compare future equivalent cost and purchasing power. No live CPI data is used.
- Finance Calculator: Choose the unknown present value, future value, payment, periodic rate or number of periods, then enter the remaining cash-flow values.
- Salary Calculator: Convert gross pay between hourly, daily, weekly, biweekly, monthly and annual equivalents using your stated work schedule. Taxes are not deducted.
- Interest Rate Calculator: Enter loan principal, equal monthly payment and payment count to infer the monthly rate and its annual equivalents.
- Sales Tax Calculator: Add your sales-tax rate to a pre-tax price or extract included tax from a total to see price, tax and after-tax amount.
- Income Tax Calculator: Estimate progressive tax using taxable income and brackets you enter. The example brackets are not official rates, and no jurisdiction’s tax law is applied automatically.
- Mortgage Calculator: Enter a home price, down payment amount, annual rate and years to estimate the monthly principal-and-interest payment.
- Loan Calculator: Use principal, a fixed annual rate and a term in months or years to compare monthly repayment and total loan interest.
- Auto Loan Calculator: Enter vehicle price, down payment, trade-in, sales tax, annual loan rate and term to estimate the financed amount and monthly payment.
- Compound Interest Calculator: Enter a starting balance, nominal annual rate, years and compounding frequency to calculate ending balance and interest earned.
- Simple Interest Calculator: Calculate interest on the original principal from an annual rate and a time in years, including fractional years.
- Investment Calculator: Project a starting amount and regular contributions over a chosen number of years using your assumed effective annual return.
- Amortization Calculator: Create a monthly fixed-rate loan schedule showing each payment, principal repaid, interest charged and remaining balance.
- Payment Calculator: Find the required monthly payment from principal, annual rate and an explicit count of monthly payments.