Calculators & Converters tools

Everyday math, date and unit calculators. Everything runs locally in your browser.

📖 New to calculators & converters? Read our Best Free Online Calculators: A Complete Guide to Unit, Date, GPA, BMI and Other Everyday Math Tools for a full comparison of every tool below and which one to pick.

Age Calculator
Calculate your exact age in years, months and days from your date of birth, plus total days lived and the days until your next birthday, in your browser.
Aspect Ratio Calculator
Simplify any width and height to its lowest terms, or lock a ratio (16:9, 4:3, 21:9, 1:1, 9:16 or custom) and solve for the missing dimension.
Bandwidth Converter
Convert between data-rate units (Mbps, MB/s, Gbps, KB/s and more) with the bits-versus-bytes factor of 8 applied correctly, right in your browser.
BMI Calculator
Calculate your BMI from height and weight in metric or imperial units, and see the WHO category plus the healthy weight range for that height.
Body Fat Calculator
Estimate body fat percentage with the U.S. Navy tape method from neck, waist and height (plus hip for women). Metric or imperial, free, in your browser.
Budget Planner
Plan a monthly budget with income and categorized expenses, live 50/30/20 guidance, and a breakdown chart. Free, private, in your browser.
Calorie Calculator
Estimate daily calorie needs (TDEE) from age, sex, height, weight and activity level, with maintain, lose and gain ranges. Runs entirely in your browser.
Compound Interest Calculator
Project compound growth from principal, rate, term, compounding and contributions, with a growth chart and year-by-year table. Free and private.
Cooking Measurement Converter
Convert cups/tablespoons/teaspoons to grams/ounces by ingredient density, plus oven temperature (F/C/gas mark) and recipe scaling.
Days Between Dates Calculator
Count the exact days between two dates, with a years and months breakdown and a weekday count, or find the date a number of days before or after another.
Dog Age Calculator
Convert dog years to human years with the real, science-based logarithmic formula (not the 7x myth), plus a size-adjusted guideline and a cat mode.
Download Time Calculator
Calculate how long a download or upload takes from file size and connection speed, with the Mbps-to-MB/s conversion handled correctly.
Electricity Cost Calculator
Enter wattage, hours a day and your price per kWh to get daily, monthly and yearly running cost, plus a standby power comparison. Free, no signup.
Feels-Like Temperature Calculator
Heat index from temperature and humidity, wind chill from temperature and wind speed, using the two National Weather Service formulas and their real limits.
Fraction Calculator
Add, subtract, multiply or divide two fractions or mixed numbers and read every step, plus an optional decimal to fraction conversion, in your browser.
Fuel Cost Calculator
Work out the fuel cost of a trip from distance, consumption in L/100km or MPG, and fuel price, with an optional round trip and a per-person split.
Golden Hour Calculator
Golden hour, blue hour, sunrise, solar noon and sunset for a list of cities or your own coordinates, plus a seven-day planning table in local time.
GPA Calculator
Enter each course's credit hours and letter grade for a live semester GPA on the plus/minus 4.0 scale, then fold in the cumulative GPA you already have.
Grade Calculator
Enter your syllabus categories with their weights and scores for a live weighted grade, then solve for the exact score you need on the final to hit a target.
Heart Rate Zone Calculator
Get five training zones in bpm from your age with the Tanaka formula, or from your own max and resting rate with Karvonen, plus a printable PDF card.
Macro Calculator
Work out daily protein, carbs and fat from your TDEE and goal (cut, maintain or bulk), with three diet presets and an even per-meal breakdown.
Moon Phase Calculator
Moon phase today or for any date, with a drawn moon, illumination percentage, next full and new moon dates, and a phase glyph on every day of the month.
Mortgage Calculator
Estimate your monthly mortgage payment from loan amount, rate and term, with an amortization schedule, chart and total-interest breakdown. Free and private.
One Rep Max Calculator
Estimate your 1RM from a weight and rep count with three published formulas at once, plus a 60 to 95 percent training table. Free and local.
Running Pace Calculator
Work out running pace, time or distance from any two, in min/km or min/mile, with treadmill speed, 5K to marathon finish times and a full split table.
Percentage Calculator
Three percentage questions in one box. X percent of Y, X is what percent of Y, and the change from A to B. Arithmetic runs in your own browser.
Interactive Periodic Table
All 118 elements with search, category and occurrence filters, three colour-by modes, a detail panel per element and a printable landscape PDF.
Quadratic Equation Solver
Enter a, b and c and see the discriminant, both roots including complex ones, the vertex form and a plotted parabola, updating as you type.
Salary to Hourly Converter
Type into any one of the annual, monthly, weekly or hourly boxes and the other three follow, for your real hours per week and paid weeks per year.
Scientific Calculator
Type a whole expression with brackets, powers, trig and logs and watch the answer update live. Degrees or radians, plus a history of the last 20.
Shoe Size Converter
Convert between US, UK, EU and centimetre shoe sizes for men, women and children, with the full chart and the matching row highlighted as you type.
Sleep Calculator
Work backward from a wake-up time or forward from a bedtime, in 90-minute cycles, with an adjustable buffer for how long you take to fall asleep.
Speech Time Calculator
Paste a script and get its spoken length at 110, 130 and 160 words per minute, plus how many words fill a target duration. Runs in your browser.
Time Zone Converter
Add several time zones, slide one time and watch them all move together, with each zone's own date, offset and day difference. Runs in your browser.
Times Tables Practice
Practice multiplication tables 2-12 with a timed or untimed quiz, instant feedback, and streak tracking, plus a free printable worksheet PDF.
Timesheet Calculator
Log clock-in/out times and breaks for a week, get decimal hours, overtime, and gross pay automatically. Free, private, with CSV/PDF export.
Unix Timestamp Converter
Convert a Unix timestamp to a readable date, or a date back to epoch seconds/milliseconds, instantly in your browser, nothing uploaded.
Tip Calculator
Work out a tip at 15, 18, 20 or 25 percent or your own figure, then split the bill and the tip across up to 100 people. Runs entirely in your browser.
Unit Converter
Convert length, weight, temperature, volume, area and speed against exact defined constants, with a quick reference line for the one unit case.
Unit Price Calculator
Compare up to 12 products by true unit price. Mix grams, kilos, ounces, pounds, millilitres, litres, fluid ounces, gallons and counts. Free and private.
Week Number Checker
Find the ISO 8601 week number for any date, convert a week number back to its date range, or list every week of a year. Runs entirely in your browser.
World Clock
See live clocks for cities around the world side by side, add/remove cities, day/night indicator, 12h/24h toggle, fullscreen wall-clock mode.

Calculators & Converters tools in action

Screenshot of the Percentage Calculator tool with Calculation set to X% of Y (e.g. 10% of 200), Value A (X in the first two modes, the starting value for % change) set to 10 — Percentage Calculator mid-process: Calculation set to X% of Y (e.g. 10% of 200), Value A (X in the first two modes, the starting value for % change) set to 10.

Screenshot of the Unit Converter tool with Category set to Length, Convert from set to Centimeters (cm), length — Unit Converter mid-process: Category set to Length, Convert from set to Centimeters (cm), length.