Free Online Converters
Three converters for the conversions that come up most often: world time zones, physical units (length, weight, temperature, volume), and color spaces (HEX, RGB, HSL, HSV). Everything runs locally in your browser.
All converters
When you'll reach for each
The three converters here cover three completely separate problem domains; the choice is usually obvious. But here's a quick guide if you're not sure.
Time zones — when you have a meeting or deadline
Use the time zone converter any time you need to coordinate across geographies. Common scenarios: scheduling a video call, translating a server log timestamp from UTC to your local time, sanity-checking when a CRON job actually runs in production. The tool handles DST automatically, so a 9am-PT meeting on a date that crosses the spring-forward boundary still displays the correct local times in every other zone.
Units — when the source uses a different system than the target
Use the unit converter when you're working between metric and imperial — recipe scaling, fitness goals (kg ↔ lb), travel (km ↔ mi), or international shipping (cm ↔ in). It also covers same-system conversions you might forget the factor for: kilojoules to calories, fluid ounces to milliliters, and the often-confused US fluid ounce versus Imperial fluid ounce (4% larger).
Colors — when designs cross format boundaries
Use the color converter when a designer hands you HEX but your tool wants HSL, or when you want to lighten a shade by adjusting just the L channel. A common workflow: paste a HEX code from a design file, then nudge the H/S/L values to derive a hover or focus state without leaving the tool.
Frequently asked questions
Why does my time zone converter sometimes show a date one day off?
That's correct behaviour — when you cross the international date line, dates legitimately differ by a day. A 9am-Sydney meeting on a Tuesday is a 6pm-Los Angeles meeting on the previous Monday. The converter shows both date and time so you can see the wrap.
Are kilograms exact when converting from pounds?
Yes — the SI defines 1 lb = 0.45359237 kg exactly. The converter uses the full precision, so round-tripping kg → lb → kg matches to within IEEE-754 double precision (about 15 significant digits).
Why does the same hex code look different in different apps?
HEX codes are sRGB by default, but some apps (especially design tools) interpret them in P3 or another wide-gamut space. The values are the same; the display is different. If colours look more saturated in one app, it's likely treating the input as P3.
Does the unit converter handle currency?
No — currency rates change minute by minute, so a static converter would be wrong by the time you used it. Use a financial site for currency conversion.