Steve Mosen

Displays the number of days until/after a specified date. Example: [kit-days-away day=25 month=12 year=2012]

Days Away

Displays the number of days until/after a specified date.

jordancalder

This plugin adds a countdown timer to your webpage with the use of a shortcode.
In Settings > WP Countdown Timer, set the datetime you want to count down towards and save.
Use the shortcode [countdown] on any page to display the countdown timer.

WordPress Countdown Timer

Wordpress plugin to add a countdown timer to your website. Display a timer and countdown to any day, time, or event.

Days Away vs WordPress Countdown Timer