This online calculator adjusts the second dimension of a picture/video, given the new first dimension, keeping the original proportions

This online calculator estimates how much your time is worth given your hourly rate

This online calculator creates captivating photo negatives by inverting the colors of your images.

This article describes how to write calculators for an image manipulation

This online calculator helps estimate the duration required to earn a specific amount based on your hourly rate.

This calculator calculates the check digit from the other digits/alphabetic characters in the entered series. The calculation is done according to the algorithm used by ICAO for machine readable travel documents. The description of the algorithm can be found below the calculator.

This online calculator selects nouns based on word length (the number of letters in the word) and the known location of some of the letters. The calculator can be useful both for solving and creating crossword puzzles.

This calculator calculates the cost of travel by multiplying the distance traveled in kilometers (or miles) by the rate per kilometer (or mile).

Splitting bills in group settings—like dinners with friends, family gatherings, or team outings—can be tricky. Our intuitive Bill Splitter calculator eliminates the guesswork! Divide expenses equally, by percentages, fixed amounts, or custom shares, while accounting for individual extras (e.g., personal drinks). Perfect for restaurants, trips, or shared events, this tool ensures fairness in seconds. Enter your details below and let the calculator handle the math!

Track your dart matches with precision using our Dart Score Calculator! Perfect for two-player games of 501, standard 301, or competitive 301 Double-In. Click the virtual dartboard to log throws (including special "BULL" and "BE" zones), use "MISS" for failed attempts, and "UNDO" to correct errors. Real-time scoring shows remaining points and suggests professional checkout paths.

Coordinating in-game activities across different time zones presents a common challenge for international gaming teams. This tool converts server-based event schedules into localized times for each team member. Specify your game server's time zone and event time, add your team members' locations, and the converter automatically displays the equivalent local times for everyone.

If you knit or crochet, you’ve likely encountered leftover partial skeins of yarn. Knowing how much yarn remains helps plan future projects, but requires a bit of math. This tool estimates yardage quickly: weigh your partial skein, input the numbers below, and get an instant result. Note that this is an approximation; factors affecting accuracy are explained in the details below.