Everyday Tools
Quick daily-life calculators: dates, times, travel budgets, tips and currency conversions.
Age Calculator
Calculate your exact age in years, months and days from your date of birth, plus total days, weeks, months lived and days until your next birthday.
Date Calculator
Calculate the number of days, weeks and business days between two dates, or add and subtract days from a date to find the resulting date and weekday.
Time Calculator
Add or subtract times and calculate the duration between two clock times in HH:MM format, with results in hours-minutes, total minutes and decimal hours.
Time Zone Converter
Convert a clock time between 17 major world time zones using IANA time zone data, with daylight saving handled automatically and the offset shown.
Hours Calculator
Work out hours between two times, deduct unpaid breaks, apply legal time rounding, and convert to decimal hours and gross pay. Handles overnight shifts.
Currency Converter
Convert any amount between currencies using an exchange rate you supply. Shows the converted amount and inverse rate, and explains mid-market vs bank rates.
Travel Budget Calculator
Estimate your total trip cost from daily accommodation, food, activities and transport plus flights. Includes per-day, per-person and 15% buffer figures.
Percent Off Calculator
Calculate the sale price after one or two stacked discounts. Stacked discounts multiply, not add — find your true effective discount and savings.
Tip Calculator
Calculate the tip amount, total bill, and cost per person for any party size. Includes an international tipping customs reference table.
Discount Calculator
Calculate the final price after a percentage discount plus optional sales tax. See how much you save. Handles stacked tax-and-discount order correctly.
Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin instantly with the exact SI-defined formulas, showing all three scales at once.
Length Converter
Convert length between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles using exact NIST/international definitions.
Weight Converter
Convert weight/mass between milligrams, grams, kilograms, tonnes, ounces, pounds and stone using exact avoirdupois definitions.
Speed Converter
Convert speed between kilometers per hour, miles per hour, meters per second and knots using exact SI and nautical-mile definitions.
Area Converter
Convert area between square meters, square kilometers, square feet, acres and hectares using exact NIST and international-foot definitions.
Volume Converter
Convert volume between milliliters, liters, cubic meters, US gallons, UK gallons, US cups and US fluid ounces with exact legal definitions.
Roman Numeral Converter
Convert numbers to Roman numerals or Roman numerals to numbers (1–3999), using standard subtractive notation with strict validation.
Energy Converter
Convert energy between joules, kilojoules, calories, kilocalories, watt-hours, kWh, BTU, therms and foot-pounds using exact SI definitions.
Angle Converter
Convert angles between degrees, radians, gradians, turns, arcminutes, arcseconds and milliradians. Every factor is exact by definition.
Time Unit Converter
Convert a duration between milliseconds, seconds, minutes, hours, days, weeks, months and years, with the month and year definitions stated explicitly.
Unit Converter
Convert length, mass, volume, area and speed between metric and imperial units using the exact NIST conversion factors. One value in, every unit out.