💼 Project Planning & Billing
Convert between billed hours, task minutes, and milestone days. Estimate total work days for hourly budgets and sprint planning.
| Seconds | Minutes | Hours (decimal) | Hours + Minutes |
|---|---|---|---|
| 60 | 1 | 0.01667 | 0 hr 1 min |
| 300 | 5 | 0.08333 | 0 hr 5 min |
| 900 | 15 | 0.25 | 0 hr 15 min |
| 1800 | 30 | 0.5 | 0 hr 30 min |
| 3600 | 60 | 1.0 | 1 hr 0 min |
| 5400 | 90 | 1.5 | 1 hr 30 min |
| 7200 | 120 | 2.0 | 2 hr 0 min |
| 86400 | 1440 | 24.0 | 24 hr 0 min |
| Hours | Days (decimal) | Weeks (decimal) | Days + Hours |
|---|---|---|---|
| 8 | 0.3333 | 0.04762 | 0 d 8 hr |
| 24 | 1.0 | 0.14286 | 1 d 0 hr |
| 40 | 1.6667 | 0.2381 | 1 d 16 hr |
| 72 | 3.0 | 0.4286 | 3 d 0 hr |
| 168 | 7.0 | 1.0 | 7 d 0 hr |
| 336 | 14.0 | 2.0 | 14 d 0 hr |
| 672 | 28.0 | 4.0 | 28 d 0 hr |
| 8760 | 365.0 | 52.143 | 365 d 0 hr |
| Unit | Days | Hours | Seconds |
|---|---|---|---|
| 1 Day | 1 | 24 | 86,400 |
| 1 Week | 7 | 168 | 604,800 |
| 1 Month (avg 30d) | 30 | 720 | 2,592,000 |
| 1 Month (avg 30.44d) | 30.44 | 730.5 | 2,629,746 |
| 1 Year (365d) | 365 | 8,760 | 31,536,000 |
| 1 Leap Year (366d) | 366 | 8,784 | 31,622,400 |
| 1 Julian Year | 365.25 | 8,766 | 31,557,600 |
| 1 Decade | 3,652.5 | 87,660 | 315,576,000 |
| Unit | Symbol | Value in seconds | Notes |
|---|---|---|---|
| Picosecond | ps | 1 × 10⁻¹² s | Light travels ~0.3 mm in 1 ps |
| Nanosecond | ns | 1 × 10⁻⁹ s | CPU cycle (3 GHz) ≈ 0.3 ns |
| Microsecond | µs | 1 × 10⁻⁶ s | High-speed camera frame: ~10 µs |
| Millisecond | ms | 0.001 s | Human eye blink: 100–400 ms |
| Centisecond | cs | 0.01 s | Used in stopwatches / sprint timing |
| Decisecond | ds | 0.1 s | Fastest human reaction ≈ 1–2 ds |
| Second | s | 1 s | SI base unit of time |
| Scenario | Hours | Minutes | Work Days (8hr) |
|---|---|---|---|
| Pomodoro Focus Session | 0.42 | 25 | 0.052 |
| Short Break | 0.083 | 5 | 0.0104 |
| Lunch Break | 1 | 60 | 0.125 |
| Half Work Day | 4 | 240 | 0.5 |
| Standard Work Day | 8 | 480 | 1 |
| Work Week | 40 | 2,400 | 5 |
| University Lecture | 1.5 | 90 | 0.188 |
| Movie Length (avg) | 2.0 | 120 | 0.25 |
Convert between billed hours, task minutes, and milestone days. Estimate total work days for hourly budgets and sprint planning.
Plan 25-min Pomodoro blocks, calculate weekly study hours, or convert class time from minutes to hours for transcripts.
Convert ms response times to seconds, or compare µs-level benchmarks. Understand nanosecond CPU cycles and millisecond page loads.
Convert flight durations between minutes and hours, or calculate total vacation days across multiple weeks or months.
Convert between sub-second units (ns, µs, ms) for physics, chemistry kinetics, or reaction-time measurements.
Convert split times: marathon pace from min/km to min/mi, or total weekly training volume from minutes to hours.
One standard day = 86,400 seconds. One 365-day year = 31,536,000 seconds. A leap year (366 days) has 31,622,400 seconds. The astronomical Julian year is 365.25 days = 31,557,600 seconds.
Our Gregorian calendar has months ranging from 28–31 days to align the year to Earth's ~365.24-day solar orbit. On average: 1 month ≈ 30.44 days or ~4.345 weeks. For rough estimates, 30 days or 4 weeks are commonly used.
Decimal hours (e.g., 2.5 hours) are easy for math calculations. Hours:minutes (2:30) are more readable for scheduling. To convert: minutes ÷ 60 = decimal hours. So 15 min = 0.25 hr, 30 min = 0.5 hr, 45 min = 0.75 hr.
For pure duration math (without dates/timezones), convert everything into a base unit (e.g., seconds), subtract or add, then convert back to the desired units. Use this converter's "Readable breakdown" panel to see the human-readable result.
SI prefixes for sub-second units: milli- (10⁻³), micro- (10⁻⁶), nano- (10⁻⁹), pico- (10⁻¹²), femto- (10⁻¹⁵), atto- (10⁻¹⁸). Larger: deca- (10), hecto- (100), kilo- (1000), mega- (10⁶), giga- (10⁹) seconds.
The default "Year" unit uses 365 days for everyday simplicity. A separate "Julian Year" option uses 365.25 days for astronomical/scientific use cases. Choose the most appropriate for your needs.