How Much Should You Really Save to Your HSA? | Personal Finance

Here’s where the guesswork comes in: Think about your medical history and your family’s history of longevity. Use that information to choose an HSA savings goal. The number should be between $150,000 and $1 million if estimating for you and a spouse. Adjust down if you’re estimating for yourself only.

Once you have a target HSA balance in mind, use a compound interest calculator to understand the contribution needed to reach your goal.

Here’s an example using the savings goal calculator at Investor.gov: Say you decide to save $300,000 for your individual healthcare costs. If you have 20 years until retirement and you expect average annual growth of 7%, the calculator suggests a monthly contribution of $610.

Finally, add the two pieces together and account for your employer contributions using these steps:

• Divide your current-year medical expenses by 12 to get a monthly number.
• Add your current monthly expenses to the monthly contribution from the calculator.
• Subtract your monthly employer contributions.