Days to Nanoseconds
Type a value in either box to convert between days and nanoseconds. The factor is 8.64e+13.
| Days | Nanoseconds |
|---|---|
| 1 day | 8.64e+13 ns |
| 2 day | 1.728e+14 ns |
| 3 day | 2.592e+14 ns |
| 5 day | 4.32e+14 ns |
| 10 day | 8.64e+14 ns |
| 25 day | 2.16e+15 ns |
| 50 day | 4.32e+15 ns |
| 100 day | 8.64e+15 ns |
How to use
- Enter a value in the Days field.
- The Nanoseconds figure appears immediately — no button to press.
- Typing in the Nanoseconds field converts back to Days the same way.
- Use the reference table for the values that come up most often.
Days to Nanoseconds formula
The factor from days to nanoseconds is 8.64e+13.
ns = day × 8.64e+13
Why this factor: the day and the nanosecond are both defined against the second, so dividing one definition by the other gives 8.64e+13 directly. Both definitions are set out in full below.
To go the other way, divide by 8.64e+13 — or use the Nanoseconds to Days converter, which is the same calculation reversed.
Worked example
Start with 15 day. Multiply by 8.64e+13 to get 1.296e+15 ns.
15 day × 8.64e+13 = 1.296e+15 ns
The converter above does this for any value you type, in either direction.
What is a day?
A day is 24 hours, one nominal rotation of the Earth.
Definition: Exactly 86,400 seconds by convention. The Earth's actual rotation drifts slightly, which is what leap seconds correct.
Where it is used: Calendars, project schedules, hotel and rental periods, and interest accrual.
What is a nanosecond?
A nanosecond is one billionth of a second — the timescale of digital electronics.
Definition: Exactly 1×10⁻⁹ second by SI prefix definition.
Where it is used: Processor and memory latency, network round trips, and high-frequency trading.
Worth knowing: Light travels almost exactly 30 cm in one nanosecond, which is why physical distance limits computer speed.
Days vs Nanoseconds
The day is a specialized unit while the nanosecond is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many nanoseconds are in a day?
One day equals 8.64e+13 nanoseconds.
What is the formula to convert days to nanoseconds?
Multiply the number of days by 8.64e+13. To reverse it, divide by 8.64e+13 instead.
How do I convert nanoseconds back to days?
Divide by 8.64e+13, which is the same as multiplying by 1.15740741e-14.
How many nanoseconds are in 10 days?
10 day works out to 8.64e+14 ns.
Is there anything to watch out for with nanoseconds?
Light travels almost exactly 30 cm in one nanosecond, which is why physical distance limits computer speed.
How is the day defined?
Exactly 86,400 seconds by convention. The Earth's actual rotation drifts slightly, which is what leap seconds correct.