How the Municipal Bond Tax-Free Interest Calculator Works
Korea offers a tax-exempt senior savings account that waives interest income tax for seniors 65+, people with disabilities, and a few other groups, up to a roughly $37,000 lifetime principal cap. The U.S. doesn't have an age-based tax-free savings product — but it has something arguably more useful for building wealth: interest from municipal bonds ("munis") issued by state and local governments is exempt from federal income tax for every investor, regardless of age, with no cap on how much you can hold.
This calculator estimates how much federal tax you avoid by holding munis instead of a comparable taxable bond or CD. Enter your investment amount, the bond's yield, how long you'll hold it, and your federal tax bracket. It also calculates the "taxable-equivalent yield" — the yield a taxable investment would need to match your after-tax return from the muni. If you're in the 32% bracket and your muni yields 3.5%, a taxable bond would need to yield about 5.15% to give you the same after-tax income, which is why munis are especially attractive for high earners.
Two caveats worth knowing: municipal bond interest is usually free of state tax too, but only if you buy bonds issued by your own state (out-of-state munis are typically still subject to your state's income tax). And while munis are exempt from regular federal tax, some "private activity" municipal bonds can still be subject to the Alternative Minimum Tax (AMT), and interest income generally still counts toward the calculation of the Net Investment Income Tax for higher earners.
Frequently Asked Questions
No. Korea's program only applies to seniors 65+, the disabled, and a few other groups, with roughly a $37,000 lifetime principal cap. Municipal bond interest is exempt from federal tax for any investor, at any age, with no principal cap — the tradeoff is municipal bonds typically pay lower yields than taxable bonds.
It's exempt from federal income tax, and often from state tax too if you buy bonds issued by your own state. It's not exempt from the Net Investment Income Tax for high earners, and some municipal bond interest can trigger the Alternative Minimum Tax (AMT) depending on the bond type.