If you are an employee, both you and your employer can make contributions to the HSA in the same year. If you are self-employed or unemployed, you can make contributions to an HSA you set up for yourself. Family members or any other person can also make contributions on your behalf. The contributions must be in cash, not stock or other property.
Limit on Contributions
The amount you or someone else can contribute to your HSA depends on whether your high deductible plan is for self-only coverage or for family coverage. The amount you can contribute also depends on your age (whether you are 55 or older). You can contribute (to your HSA) up to the amount of your annual deductible (for your high deductible plan), subject to maximum amounts defined by the IRS. These dollar-amount limits are subject to change periodically, and can be found in IRS Publication 969.
In order to be able to claim the maximum deduction for the year, you must have had the same coverage all year. If you did not, and cannot claim the maximum deduction, there is a worksheet in the instructions for Form 8889 to figure your contribution limit. By using this worksheet, you are calculating your average deductible for the year. If you are married with family coverage and both you and your spouse are eligible for an HSA, you will need to allocate the deductible for family coverage between you. You can allocate the deductible any way you agree upon, but if you do not agree, you have to allocate the deductible equally between you.
If you are age 55 or older, your contribution limit is increased. The amount by which it increases can also be found in IRS Publication 969 and in the instructions for Form 8889.
If you had more than one HSA during the year, the total contributions to all your HSAs are subject to the same maximum limit.
Contribution Deductions
You will have to reduce your contribution limit by the following:
Any contributions that are made to an Archer MSA that you have, including employer contributions, and
Any contributions that your employer makes to your HSA that are not included in your income. In other words, the total contributions you and your employer make cannot exceed the maximum amount.