Everyday calculators
Practical day-to-day calculators: dates, tips, fuel cost, time math and more.
Add Days to a Date Calculator
Free "add days to date" calculator — pick a start date and a number of days (positive or negative) to find the resulting date. Handles leap years.
Age Calculator
Free age calculator — type a birthdate and a reference date and get exact age in years, months and days. Defaults to today. Runs in your browser.
Aspect Ratio Calculator
Free aspect ratio calculator — get the reduced ratio of a width × height, or resize a width or height while keeping a target ratio. Works in your browser.
Business Days Calculator (weekdays only, holidays optional)
Free business-days calculator — counts weekdays between two dates and subtracts holidays you list. Use for SLAs, deadlines, contract terms.
Days Between Dates Calculator
Free days between dates calculator — type two dates and get the exact number of calendar days between them. Works in your browser, no sign-up.
Days Until Calculator (countdown to any date)
Free days-until calculator — pick a future date and see how many days, weeks and remaining days until it. Works for past dates too ("passed N days ago").
Dog and Cat Years Calculator
Free dog years calculator using modern, size-adjusted aging — not the old "times 7" myth. Convert your dog's or cat's age to human years instantly in your browser.
Electricity Cost Calculator
Free electricity cost calculator — enter wattage, hours per day, and your rate to find out what any appliance costs to run. Instant, no signup.
Fuel Cost Calculator
Free fuel cost calculator — work out how much a trip will cost in fuel from distance (km), consumption (km/L), and price per litre. Runs in your browser.
GPA Calculator
Free GPA calculator — compute your weighted grade point average on the 4.0 scale from letter grades and credit hours. Handles +/− modifiers. Runs in your browser.
Percentage Change Calculator
Free percentage change calculator — find the % increase or decrease between two numbers. Perfect for price changes, growth rates, and comparisons. Runs in your browser.
Time Duration Calculator
Free time duration calculator — type a start time and end time and get the hours and minutes between them. Handles times that cross midnight. Works in your browser.
Unit Price Calculator
Free unit price calculator — divide price by quantity to find the cost per unit. Lets you compare grocery deals across different sizes. Runs in your browser.