This Igbo calendar app is the best reference for determining the market day of any Gregorian date.

You can look up the market day for any date in your life. It works by matching your current location (country code, state code and city code), the year and day (month and day are optional).

It also displays the time zone you are in, so you don't have to remember which time zone you are in.

So just enter your city, state and country code and click on the "Get Igbo Calendar" button to get the result.

To make it more interactive, it's been built to look like wall calendars in homes and businesses.