Tomorrow is a leap day – February 29 – an extra day that shows up in February ever four years (well, sort of. Years that are evenly divisible by 100 are not leap years, unless they are also evenly divisible by 400, in which case they are leap years).

That has some implications for domain registrations. Sadly, it does not mean you get four years for the price of one.

Rather, most registries have policies defined to account for registrations that happen on leap days.

In most cases, domains registered on February 29 will expire the following year on February 28. A few registries use March 1 instead.

That begs the question – is it possible for a domain to expire on February 29? The answer is yes depending on the specific extension and registry policies.

For example, if you register a .COM domain on February 29, 2012 for a four-year term, you’d expect the domain to expire on February 29, 2016. However, the registry policy states that .COM domains registered on February 29 will always expire on February 28.

Does that mean that there will be no expiring .COM domains on February 29? A quick check around seems to suggest that the answer is yes. Anyone have a more definitive answer?

You can consult the documentation for a list of which registry uses which dates for expiry. Check page 72 of the Reseller’s Guide to Domain Name Registration and Management. You’ll note that .BZ, .IN and .WS do in fact allow four-year registrations done on leap days to expire on leap days (assuming there is one four years after the registration).

Crystal Peterson from .CO Internet has said in a blog post today that a four year .CO domain registration done on March 1, 2012, would lead to a domain with an expiry of February 29, 2016. Anyone care to test that hypothesis tomorrow?

The good news? OpenSRS has all the logic built in to properly account for and handle leap year registrations for all TLDs and services.

Enjoy the extra day!