How to convert Datetime to Unix timestamp in Scheme

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    (import (srfi 19))

    (define my-date (make-date 0 30 12 15 7 2018 0)) ; Date: 2018-07-15 12:30:00
    (define unix-timestamp (date->seconds my-date))
    
    (display unix-timestamp)
    (newline)

Output:

1531656600

Example only. There may be multiple ways to perform this operation.

Code Explanation

In this Scheme example, a date object is created for '2018-07-15 12:10:00' using the make-date function, which allows you to specify the second, minute, hour, day, month, year, and time zone. The date->seconds function converts this date structure to a Unix timestamp.
The result is then printed using display.

Convert Unix timestamp to Date in Scheme

Other useful Scheme date functions (SRFI-19)

Function	Description	Example
`seconds->date`	Converts a Unix timestamp (in seconds) to a `date` structure.	`(seconds->date 1514764800)` returns 2018-01-01 00:00:00+00:00
`date->seconds`	Converts a `date` structure to a Unix timestamp.	`(date->seconds (make-date 0 30 12 15 7 2018 0))` returns 1531656600
`make-date`	Creates a `date` structure from second, minute, hour, day, month, year, and time zone components.	`(make-date 0 30 12 15 7 2018 0)` creates the date 2018-07-15 12:30:00.
`date->string`	Converts a `date` structure to a formatted string.	`(date->string date)` returns a formatted string like 2018-07-15 12:30:00+00:00.
`current-date`	Returns the current date as a `date` structure.	`(current-date)` returns the current date and time.
`date-year`	Extracts the year from a `date` structure.	`(date-year (current-date))` returns the current year.
`date-month`	Extracts the month from a `date` structure.	`(date-month (current-date))` returns the current month.
`date-day`	Extracts the day of the month from a `date` structure.	`(date-day (current-date))` returns the current day of the month.
`date-hour`	Extracts the hour from a `date` structure.	`(date-hour (current-date))` returns the current hour.
`date-minute`	Extracts the minute from a `date` structure.	`(date-minute (current-date))` returns the current minute.
`date-second`	Extracts the second from a `date` structure.	`(date-second (current-date))` returns the current second.

Current Unix Timestamp SECONDS SINCE JAN 01 1970

Current UTC Time

2025-08-20