HSA Contribution Calculator

How it is calculated

The tool prorates the annual limit by the months you were eligible, then takes off what your employer has already put in.

limit = IRS limit + 1,000 (if age 55 or older)
prorated limit = limit × months eligible ÷ 12
your maximum = max(0, prorated limit − employer contribution)

The IRS limit is a field you fill in yourself, because it changes with coverage type (self-only or family) and from year to year; the starting value shown is only a placeholder, so replace it with the current figure for your coverage. The age field adds a flat $1,000 catch-up. Note that in this tool the catch-up is prorated together with the base limit, and months can be 0 to 12 (decimals work). Employer money counts against the same limit, and if it already exceeds the prorated limit the result is $0.00. The tool applies simple proration only and no other special rules.

Common mistakes

• Leaving the IRS limit at the pre-filled value. The limit differs for self-only and family coverage and changes by year, so use the official figure for your situation.
• Forgetting that employer contributions count toward the limit. Money your employer deposits reduces your room one for one, so ignoring it can lead to an excess contribution.
• Entering the months you were enrolled in a plan rather than the months you were HSA-eligible. Only months with qualifying high-deductible coverage count.
• Selecting the age 55 catch-up when you are younger. Choosing Yes adds $1,000 to the limit whether or not you qualify.
• Treating the result as tax advice. It is a simple calculation, so confirm special cases such as mid-year coverage changes or spouses with their own accounts.