Ruby Convert Date to Milliseconds

1. Introduction

Ruby developers often need to convert date values into milliseconds, especially when they are dealing with precise time measurements or when interfacing with systems that require time to be represented in milliseconds since the epoch. This conversion can be essential for timestamping, scheduling, or logging events with high accuracy.

In computing, the term 'milliseconds since the epoch' refers to the number of milliseconds that have elapsed since 00:00:00 Coordinated Universal Time (UTC), Thursday, 1 January 1970, not counting leap seconds. This is a common time measurement used in programming. Ruby can calculate this value by converting a Date object to a Time object and then multiplying the seconds since the epoch by 1,000 to convert to milliseconds.

2. Program Steps

1. Create a Date object with the desired date.

2. Convert the Date object to a Time object.

3. Convert the Time object to seconds since the epoch, then convert to milliseconds.

4. Output the result in milliseconds.

3. Code Program

# Step 1: Require the date library and create a Date object
require 'date'
date =, 4, 5)

# Step 2: Convert the Date object to a Time object at the beginning of the day
time = date.to_time

# Step 3: Convert the Time object to seconds since the epoch and then to milliseconds
milliseconds_since_epoch = (time.to_f * 1000).to_i

# Step 4: Output the result in milliseconds
puts milliseconds_since_epoch




1. date is created as an instance of the Date class, representing the 5th of April, 2023.

2. date.to_time converts the Date object to a Time object at the beginning of the day in the local time zone.

3. time.to_f gives the float representation of seconds since the epoch. Multiplying this by 1,000 converts the value to milliseconds, and to_i changes it to an integer.

4. puts milliseconds_since_epoch prints the final result to the console, displaying the number of milliseconds since the epoch for the given date at midnight.