jCountdown Mega Package for WordPress is a highly customizable plugin, you can easily to create / load shortcodes in admin panel, and add Countdowns in your Post, Page and Sidebar with Shortcodes

Countdown Settings

timeText
timeZone
style – Flip, Slide, Metal or Crystal
color – Black or White
width
textGroupSpace
textSpace
reflection (this setting works in Firefox, Chrome, Safari, Opera and most mobile browser)
reflection Opacity (this setting works in Firefox, Chrome, Safari, Opera and most mobile browser)
reflection Blur (this setting works in Firefox, Chrome, Safari and most mobile browser)
dayTextNumber
displayDay
displayHour
displayMinute
displaySecond
displayLabel
onFinishRedirectURL – Redirect URL when time is up