Add and Subtract Time Intervals : Hours, Minutes, Seconds

A dead-simple calculator that works as you type

Enter times in the format  10h 20m 30s  or  10h20m30s 

You may also like:

Shaun's Fill-in-the-Blanks Percentage Calculator is hands-down the easiest way to figure out percentages. If you've ever struggled with questions like "What percent larger is A than B?" this is the tool for you.

Shaun's Word Count Tool allows you to instantly get the word count, character count, and paragraph count of any string.

Shaun's No-Cruft Excel to HTML Table Converter is a simple utility that allows you to paste data from an Excel spreadsheet (or an HTML table) and convert it to a new HTML table that is free of extraneous formatting.

IntelliCAPS — Intelligently convert ALL CAPS text to small caps.

Shaun's urlencode/urldecode tool allows you to paste in a text string and convert it between normal text and a URL-encoded string. This tool uses PHP's urlencode() and urldecode() functions.

Shaun's Homeland Reassigner: We're born into our native countries by the luck of the draw. The Homeland Re-Assigner uses world population data to simulate this process. It produces statistically accurate representations of where else you might have ended up.

Shaun's Soulmate Seeker: As with the Homeland Reassigner, the Soulmate Seeker uses world population data to generate a statistically accurate "best guess" about where in the world your soulmate lives. Hint: It's probably far away.

Shaun's Chord Transposer: Drop in a bunch of chords, then specify which key you'd like to change them to. Very handy for guitar players, but useful for practically any instrument.