What is a time units converter?
A time units converter translates between units of duration — seconds, minutes, hours, days, weeks, months, years, decades, centuries. It also handles smaller units (milliseconds, microseconds, nanoseconds) for software, physics, and electronics work.
Most time conversions are straightforward arithmetic (60 seconds = 1 minute), but the larger units carry traps: months have 28-31 days, years have 365 or 366, "business days" exclude weekends and holidays. This calculator handles fixed conversions; for date arithmetic ("how many days between two dates"), use the Date Difference calculator.
Unit conversion table
| Unit | In seconds | Notes |
|---|---|---|
| 1 nanosecond (ns) | 10⁻⁹ s | CPU clock cycles |
| 1 microsecond (μs) | 10⁻⁶ s | Network latency |
| 1 millisecond (ms) | 10⁻³ s | Web request times |
| 1 second (s) | 1 | SI base unit |
| 1 minute | 60 | |
| 1 hour | 3,600 | |
| 1 day | 86,400 | 24 × 3,600 |
| 1 week | 604,800 | 7 days |
| 1 month (avg) | ~2,629,800 | 30.44 days |
| 1 year (Julian) | 31,557,600 | 365.25 days |
| 1 year (common) | 31,536,000 | 365 days |
| 1 decade | ~315,576,000 | 10 years |
| 1 century | ~3,155,760,000 | 100 years |
Worked example
Convert 2 hours 45 minutes to seconds:
2 hours × 3,600 = 7,200 seconds
45 minutes × 60 = 2,700 seconds
Total = 7,200 + 2,700 = 9,900 seconds
Convert 86,400 seconds to days:
86,400 / 86,400 = 1 day
Convert 1 year to minutes:
365 × 24 × 60 = 525,600 minutes
(Yes — the "525,600 minutes" from the musical Rent counts a non-leap year.)
Common conversions
| Conversion | Result | Use case |
|---|---|---|
| 1 day → hours | 24 | Daily planning |
| 1 week → hours | 168 | Working hours per week |
| 1 month → hours | ~730 | Salary hourly conversion |
| 1 year → hours | 8,760 | Annual energy bills |
| 1 year → seconds | ~31.5 million | Roughly π × 10⁷ — a physics mnemonic |
| 1 century → days | 36,525 | Includes leap years |
Components and inputs
Source unit and target unit
Select what you have and what you want. The calculator does the conversion factor lookup automatically.
Value
The number in the source unit. Decimals are allowed (e.g., 2.5 hours = 9,000 seconds).
Result
Displayed in the target unit, with full precision and rounded display.
Variants and edge cases
Month — variable definition
- 30.44 days (avg) — used by financial calculations, Excel
- 30 days — used by simple-interest day-count conventions
- 30 or 31 days (actual) — for calendar-based date math
- 28 or 29 days (Feb) — leap year handling
When precision matters (interest accrual, contract durations), use actual days not average months. The Date Difference calculator handles that.
Year — variable definition
- 365 days — common year (most calculations)
- 365.25 days (Julian) — astronomy and physics
- 365.2422 days (tropical) — astronomy / Earth's orbit
- 365 or 366 days (Gregorian) — calendar reality
Working time
- Business day = 8 hours (typical) but varies by jurisdiction
- Working week = 40 hours (US), 48 hours (India statutory cap), 35 hours (France)
- Working month = ~22 business days (excluding weekends)
- Working year = ~250–260 business days (excluding weekends + public holidays)
For salary-to-hourly conversion: annual salary / (52 weeks × hours-per-week) = hourly rate. ₹6 lakh / (52 × 40) = ₹288/hour. Or use the Salary Calculator.
Common applications
| Use case | Conversion |
|---|---|
| Annual salary → hourly | Salary / (52 weeks × hrs/week) |
| Software request latency | ms or μs |
| Project duration | Days or weeks |
| Loan tenure | Months or years |
| Childcare / leave | Weeks or months |
| Cosmic timescales | Millions of years (Myr), billions (Gyr) |
| CPU clock | GHz = 10⁹ Hz → 1 cycle = 1 ns |
Worked example: project planning
A project is estimated at 6 weeks of work for 3 engineers (full-time). What's the total person-hours?
6 weeks × 5 working days × 8 hours = 240 hours per person
240 hours × 3 engineers = 720 person-hours
If you're billing at ₹2,000/hour for outsourced contractors:
720 hours × ₹2,000 = ₹14.4 lakh
This is why estimates compound — multiplying out weeks → hours → cost surfaces the magnitude quickly.
Software engineering specifics
Latency units developers care about:
| Operation | Typical time |
|---|---|
| L1 cache hit | 1 ns |
| L2 cache hit | 4 ns |
| Main memory access | 100 ns |
| SSD read (4 KB) | 150 μs |
| HDD seek | 10 ms |
| Network round-trip (same region) | 1–5 ms |
| Network round-trip (cross-continent) | 100–200 ms |
| Disk read (sequential, 1 MB) | 1 ms |
Remember: humans perceive >100 ms as laggy. Web pages should respond to interactions in <100 ms. Page loads should be <3 seconds. Anything in microseconds or nanoseconds is invisible to users — that's CPU / memory territory.
Considerations
- Leap seconds. UTC has had 27 leap seconds inserted since 1972. Most code ignores them; high-precision astronomy does not.
- Time zones don't affect duration. "2 hours from now" is 2 hours regardless of timezone. Time zones only affect clock readings (date and time-of-day).
- Calendar months ≠ 30 days. If a contract says "delivery in 3 months", that's ~91 days, not 90.
- Year start. Financial year in India is April 1 – March 31. Calendar year is January 1 – December 31. Contracts must specify.
Limitations
- The calculator handles fixed-factor conversions only. For "how many days from 1 Jan 2026 to 1 Jul 2026" — use the Date Difference Calculator.
- No business-day awareness — weekends and holidays are not excluded.
- No timezone arithmetic — use a dedicated Timezone Converter.
- "Light-year" is a distance, not a time (about 9.46 × 10¹⁵ m). It's frequently confused; the converter doesn't handle it.
Related calculators
- Date Difference — calendar-aware days between two dates
- Age Calculator — years/months/days from a birth date
- Working Days — excludes weekends and holidays
- Timezone Converter — UTC offsets
- Salary — annual ↔ monthly ↔ hourly
- Pace — running time-per-distance
Final note. Time arithmetic looks trivial but has hidden complexity in larger units (months, years) and contexts (business days, leap years). When precision matters — contracts, payroll, interest — always use actual calendar days via the Date Difference calculator. This time-units converter handles fixed factors; the calendar calculator handles real-world dates.