About dhh5.com
dhh5.com is a small collection of free online converters and calculators. The idea is simple: when you need to convert one value into another, you should not have to sign up, sit through ads, or upload your data to a stranger's server.
What makes these tools different
Everything runs in your browser
No value you type ever leaves your device. The conversion happens in JavaScript on the page itself, which also means the tools work instantly and keep working if your connection drops.
No signup, no paywall, no artificial limits
Every tool is free and unlimited. There is no account to create and nothing is locked behind a "pro" tier.
Show the maths, not just the answer
Each tool explains the formula behind it and includes a reference table of common values. If you want to check the result by hand, you can.
Who the tools are for
- Developers — text/binary, JSON/XML, epoch timestamps, number bases
- Designers — RGB/HEX and RGBA/HEX color conversion
- Musicians and audio engineers — BPM, note lengths, delay and reverb timing
- Pilots, sailors and weather watchers — knots, MPH and other unit conversions
- Anyone working across time zones — UTC to US Eastern time, with daylight saving handled
Accuracy and corrections
We aim for correctness over convenience, and we would rather be told about a mistake than leave it in place. Time zone rules in particular change more often than people expect, and unit definitions vary between countries.
If a tool gives you a result you believe is wrong, please get in touch with the input you used and what you expected. Bug reports are genuinely appreciated.
A note on the numbers
These tools are provided for general use. They are not a substitute for certified reference data in safety-critical contexts such as flight planning, navigation or medical dosing. Always confirm critical figures against an authoritative source.
Last updated: August 31, 2026