How much can I contribute to my HSA if I become HSA-eligible after Jan 1?

If you became HSA-eligible after January 1st up until December 1st, you can contribute a prorated amount based on the number of months you were eligible during the year. 

Please refer to the article “How much can I contribute to my HSA if I lose eligibility mid-year?” for more information about calculating your pro-rated contribution. 

If you become eligible by December 1st, you may be able to contribute the maximum annual contribution based on your plan type under the last-month rule. Under this rule, if you are HSA-eligible December 1st, you are considered having HDHP coverage for the full year, as long as you didn’t otherwise have coverage. 

If you make the full annual contribution to your HSA based on the last-month rule, you must remain an eligible individual during the testing period. The testing period begins with the last month of your tax year and ends at the end of the following calendar year.

Note: If you take advantage of the last-month rule and fail to remain eligible for the testing period for any reason other than death or becoming disabled, you will have to include in your taxable income any contributions for months that you were not HSA-eligible.