How long do you have to wait to qualify for the capital gains tax exemption? I know it's two years but is that tax years or month specific?

[canibecoolsoon]

If I used the exemption on a home sale in November 2020, when could I sell again and qualify?

[PatriciaV]

The general rule is 24 months or 730 days (not necessarily consecutive).

This period is defined in IRS Pub 523 Selling Your Home, under the eligibility tests for exclusion of gain:

Residence Eligibility

If you owned the home and used it as your residence for at least 24 months of the previous 5 years, you meet the residence requirement. The 24 months of residence can fall anywhere within the 5-year period, and it doesn't have to be a single block of time. All that is required is a total of 24 months (730 days) of residence during the 5-year period. 

Further, under the next test, Lookback

If you didn't sell another home during the 2-year period before the date of sale (or, if you did sell another home during this period, but didn't take an exclusion of the gain earned from it), you meet the look-back requirement. You may take the exclusion only once during a 2-year period.

[Mike9241]

to get the full exemption on the second house you own it would have to be your primary residence for 2 years out of 5 years before the sale.  you also can only use the full 121 exclusion once every 2 years. so if you used it in 11/20, you would have to wait until 11/22 if using months or 730 days from sale if you use days. but that means you must also occupy the second house as a primary residence for 730 days after first sale.

note that you may be entitled to a reduced exclusion if you sell for certain reasons such as health, qualified job move, or certain unforeseen circumstances