Day to Second Converter

1 Day = 86400 Second
Day (d) ➜ Second (s)
 
d

Day vs Second Comparison Chart

Source - DayTarget - Second

Day (d) - Definition and Overview

What is Day?

The unit of measurement day (d) is defined as 86,400 SI seconds. Day can also be defined as each of the twenty-four-hour periods, reckoned from one midnight to the next, into which a week, month, or year is divided, and corresponding to a rotation of the earth on its axis.

Summary

  • A day is a unit of time equal to 24 hours or 86,400 seconds
  • It is based on the rotation of the Earth on its axis and is used to measure the length of time between two successive noons
  • Days are commonly divided into smaller units such as hours, minutes, and seconds.

Second (s) - Definition and Overview

What is Second?

The second(sec,s) is the base unit of time in the International System of Units (SI). It is defined as 1/86400 of a day. Multiples of seconds are usually counted in minutes and hours.

Summary

  • The second is the fundamental unit of time in the International System of Units (SI)
  • It is defined based on the vibrations of cesium atoms
  • One second is the duration of 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom.

How to Convert Day to Second?

1 Day is equal to 86400 Second. To convert Day to Second, use this simple formula:

Second = Day x 86400

So, just multiply the number of Day by 86400 to get equivalent value in Second.

Example 1:

Convert 5 Day to Second
5 x 86400 = 432000 Second

Example 2:

Convert 7.5 Day to Second
7.5 x 86400 = 648000 Second

Author Information

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Rajesh V U

Full-Stack Developer & Storage Technologist | Creator of UnitSmash.com
Last updated: June 1, 2026

I am a Storage Technologist with strong experience in enterprise storage systems, Angular development, and web-based tools. I enjoy building practical calculators, converters, and utilities, and I also create original cartoons. I share my tools, articles, and creative work on my personal website, rajeshvu.com.