Time Duration Converter
Convert durations between 10 units — millisecond, second, minute, hour, day, week, month (30d), year (365d), decade, century. For calendar-exact date math, use the Date Difference tool instead.
What powers the Time Duration Converter
10 units from millisecond to century
All conversions simultaneous
Month = 30 days (average); Year = 365 days
Useful for back-of-envelope duration math
Instant
Why the Time Duration Converter is different
Browser-native
The Time Duration Converter runs entirely in your browser. Input is processed locally — never uploaded, never logged, never cached anywhere outside your device.
No artificial limits
No daily quotas, no character ceilings, no "upgrade for more" walls. Every feature is the complete feature — the same on the first use as the thousandth.
Production-grade quality
Built to the same engineering bar as paid SaaS tools — accurate algorithms, audited logic, responsive design and accessibility-tested interactions.
Common use contexts
- Project planning — converting weeks to days for sprints
- Estimating — hours to months for long projects
- Scientific — millisecond to second for performance data
- Comparing — seconds to years for long-running processes
Private and secure
Zero upload
All processing happens in your browser. Input is never transmitted, logged or cached.
Works offline
Once the page loads, the tool runs without an internet connection. No network calls happen during use.
No tracking
No accounts, no cookies for tool state. Only aggregate analytics count visits at the page level.