How to Convert Date to Numeric in R (With Examples)

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There are two methods you can use to convert date values to numeric values in R:

Method 1: Use as.numeric()

as.numeric(my_date)

This will return the number of seconds that have passed between your date object and 1/1/1970.

Method 2: Use Functions from the lubridate package

library(lubridate)

#get seconds value in date object
second(my_date)

#get minutes value in date object
minute(my_date)

...
#get year value in date object
year(my_date)

This will return the value for the seconds, minutes, years, etc. from your date object.

The following examples show how to use each method in practice.

Method 1: Use as.numeric()

The following code shows how to convert a date object to numeric using the as.numeric() function:

#create date object
my_date <- as.POSIXct("10/14/2021  5:35:00 PM", format="%m/%d/%Y  %H:%M:%S %p")

#view date object
my_date

[1] "2021-10-14 05:35:00 UTC"

#convert date object to number of seconds since 1/1/1970
as.numeric(my_date)

[1] 1634189700

#convert date object to number of days since 1/1/1970
as.numeric(my_date) / 86400

[1] 18914.23

#convert date object to number of years since 1/1/1970
as.numeric(my_date) / 86400 / 365

[1] 51.81982

Based on the output we can see:

• There is a difference of 1,634,189,700 seconds between our date object and 1/1/1970.
• There is a difference of 18,914.23 days between our date object and 1/1/1970.
• There is a difference of 51.81982 years between our date object and 1/1/1970.

Method 2: Use Functions from the lubridate Package

The following code shows how to convert a date object to numeric using functions from the package in R:

library(lubridate)

#create date object
my_date <- as.POSIXct("10/14/2021  5:35:00 PM", format="%m/%d/%Y  %H:%M:%S %p")

#view date object
my_date

[1] "2021-10-14 05:35:00 UTC"

#extract various numerical values from date object
second(my_date)

[1] 0

minute(my_date)

[1] 35

hour(my_date)

[1] 5

day(my_date)

[1] 14

month(my_date)

[1] 10

year(my_date)

[1] 2021

Using these functions, we can extract the seconds, minutes, hours, days, months, and year values from our date object.

The following tutorials explain how to perform other common conversions in R: