How Time Units Relate to Each Other
Every time unit is a fixed multiple of the second. Starting from the smallest, each step up multiplies the previous unit by a set factor:
| Unit | Equal to | Seconds |
|---|---|---|
| 1 Nanosecond | 1 × 10⁻⁹ seconds | 0.000000001 |
| 1 Microsecond | 1,000 nanoseconds | 0.000001 |
| 1 Millisecond | 1,000 microseconds | 0.001 |
| 1 Second | 1,000 milliseconds | 1 |
| 1 Minute | 60 seconds | 60 |
| 1 Hour | 60 minutes | 3,600 |
| 1 Day | 24 hours | 86,400 |
| 1 Week | 7 days | 604,800 |
| 1 Month (avg) | 30.4375 days | 2,629,800 |
| 1 Year | 365.25 days | 31,557,600 |
| 1 Decade | 10 years | 315,576,000 |
| 1 Century | 100 years | 3,155,760,000 |
How to Convert Between Units
To convert from one time unit to another, multiply by the source unit’s seconds value and then divide by the target unit’s seconds value.
Formula: result = value × (from_unit_in_seconds ÷ to_unit_in_seconds)
Example — hours to minutes: 2.5 hours × (3,600 ÷ 60) = 2.5 × 60 = 150 minutes
Example — days to seconds: 3 days × (86,400 ÷ 1) = 259,200 seconds
Example — minutes to hours: 90 minutes × (60 ÷ 3,600) = 90 × 0.01667 = 1.5 hours
Very Large and Very Small Values
At the extremes of the scale, the numbers become enormous or microscopic. A single nanosecond is one billionth of a second — the time it takes light to travel about 30 centimeters. By contrast, a century is over 3.15 billion seconds. Converting between these two extremes produces numbers that span 19 orders of magnitude, which is why the converter uses scientific notation (such as 3.1558 × 10¹⁸) for values that would otherwise be too long to read.
Nanoseconds and microseconds are used in computing and electronics, where processor clock cycles and signal propagation times are measured at this scale. Milliseconds are relevant for human reaction times, networking latency, and audio/video frame rates. Everything from seconds upward covers human-scale time: meetings in minutes, workdays in hours, project timelines in weeks and months, and historical spans in decades or centuries.
Common Quick Reference
- 1 hour = 60 minutes = 3,600 seconds
- 1 day = 24 hours = 1,440 minutes = 86,400 seconds
- 1 week = 7 days = 168 hours = 604,800 seconds
- 1 month ≈ 4.348 weeks ≈ 30.44 days ≈ 730.5 hours
- 1 year = 12 months = 52.18 weeks = 365.25 days = 8,766 hours
- 1 decade = 10 years = 3,652.5 days
- 1 century = 100 years = 36,525 days