Day to Second Converter
1 d = 86,400 s — convert instantly with formula and table.
Type a value above and it converts instantly — no button to press, no page reload, and the math runs entirely in your browser.
Quick answer: one day equals 86,400 seconds. So to convert days to seconds, multiply by 86,400.
How to convert days to seconds
seconds = days × 86,400
The civil day is exactly 86,400 seconds. Earth's actual rotation drifts slightly, which is why leap seconds occasionally exist.
The second is the SI base unit of time, defined by 9,192,631,770 oscillations of a cesium atom — the tick behind every clock on Earth.
Day to Second conversion table
| Day (d) | Second (s) |
|---|---|
| 0.01 d | 864 s |
| 0.1 d | 8,640 s |
| 0.25 d | 21,600 s |
| 0.4 d | 34,560 s |
| 0.75 d | 64,800 s |
| 1.25 d | 108,000 s |
| 1.75 d | 151,200 s |
| 2.5 d | 216,000 s |
| 3.5 d | 302,400 s |
| 4.5 d | 388,800 s |
| 6 d | 518,400 s |
| 8 d | 691,200 s |
| 10 d | 864,000 s |
| 12 d | 1,036,800 s |
| 14 d | 1,209,600 s |
| 16 d | 1,382,400 s |
| 18 d | 1,555,200 s |
| 20 d | 1,728,000 s |
| 24 d | 2,073,600 s |
| 26 d | 2,246,400 s |
| 30 d | 2,592,000 s |
| 35 d | 3,024,000 s |
| 45 d | 3,888,000 s |
| 55 d | 4,752,000 s |
| 65 d | 5,616,000 s |
| 75 d | 6,480,000 s |
| 85 d | 7,344,000 s |
| 95 d | 8,208,000 s |
| 110 d | 9,504,000 s |
| 125 d | 10,800,000 s |
| 175 d | 15,120,000 s |
| 250 d | 21,600,000 s |
| 350 d | 30,240,000 s |
| 450 d | 38,880,000 s |
| 600 d | 51,840,000 s |
| 750 d | 64,800,000 s |
| 900 d | 77,760,000 s |
| 1,500 d | 129,600,000 s |
| 2,500 d | 216,000,000 s |
| 10,000 d | 864,000,000 s |
Need the opposite direction? Use the Second to Day converter, or read our complete guide to time conversions for every formula in one place.
Frequently asked questions
How many seconds are in one day?
One day equals 86,400 seconds. Multiply any day value by 86,400 to get seconds.
What is 10 days in seconds?
10 days equal 864,000 seconds (10 × 86,400).
Is the day to second conversion exact?
The conversion factor used here (86,400) is based on the internationally agreed definitions of both units, so results are exact up to rounding of the final decimal places.
Is my data stored when I use this converter?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is sent to a server, logged or stored.