The tax-equivalent yield calculator above converts a municipal bond's tax-free yield into the yield a taxable bond would need to offer to actually leave you with the same amount of money in your pocket. Enter the muni's stated yield, your federal and state marginal tax rates, and whether the bond is also exempt from state tax, and the tool does the rest.
This is one of those calculations that sounds simple but trips up a lot of investors comparing a 3.5% muni bond to a 5% corporate bond and assuming the corporate bond wins outright. It might β but not necessarily, once taxes enter the picture. Arb Digital built this calculator as one of our free tools to make that comparison apples-to-apples in seconds.
What This Tax-Equivalent Yield Calculator Does
It takes a municipal bond's tax-free yield and "grosses it up" to show what a fully taxable bond would need to yield to match it after taxes are paid. It factors in your federal marginal tax rate, your state marginal tax rate, and whether the muni is also exempt from state tax β which matters a lot if you're buying a bond issued by your own state of residence versus an out-of-state muni.
How to Use It
- Enter the municipal bond's yield as a percentage β this is the tax-free rate quoted by the issuer or your broker.
- Enter your federal marginal tax rate β the top bracket that applies to your last dollar of income, not your average rate.
- Enter your state marginal tax rate, or 0 if you live somewhere with no state income tax.
- Select whether the bond is also exempt from state tax. Munis issued by your home state are typically exempt from both federal and state tax; out-of-state munis are usually federal-exempt only.
- Click Calculate to see the taxable-equivalent yield and the combined rate used.
The Formula β How It's Calculated
The core formula is: tax-equivalent yield = tax-free yield Γ· (1 β combined marginal tax rate). If your muni bond is exempt from state tax too, the combined rate used is just your federal rate. If it's only exempt from federal tax (the more common case for out-of-state munis), the combined rate adds your state rate on top of your federal rate. For example, a 3.5% muni yield for someone in the 24% federal bracket, with no state exemption, produces a taxable-equivalent yield well above 4.5% β meaning a taxable bond would need to clear that bar just to tie. For background on municipal bonds and how they're taxed, see the SEC's Investor.gov guide to municipal bonds.
Why You Can't Just Compare Yields Side by Side
A taxable bond's quoted yield is what you earn before the IRS takes its cut. A municipal bond's quoted yield is usually already what you keep β interest from most munis is exempt from federal income tax, and often from state tax too if you buy a bond issued within your own state. Comparing a 5% taxable yield to a 3.5% tax-free yield at face value makes the taxable bond look like the clear winner. But run the tax-equivalent yield math for someone in a high bracket, and the muni frequently pulls ahead, or at least closes the gap significantly.
This is exactly why munis are marketed heavily to higher-income investors and retirees living off investment income: the higher your marginal tax rate, the more valuable the tax exemption becomes, and the higher the taxable-equivalent yield climbs for the exact same muni bond. Someone in the 12% bracket might find a taxable bond genuinely beats the muni after tax. Someone in the 35% bracket, comparing the identical two bonds, might find the muni is clearly superior.
In-State vs Out-of-State Munis: Why It Changes the Math
Most municipal bond interest is exempt from federal income tax regardless of which state issued it. Where it gets more interesting is state tax. If you buy a bond issued by your own state of residence (or certain local governments within it), that interest is typically exempt from your state income tax as well β a double exemption. Buy a muni issued by a different state, and that interest is usually still taxable at the state level, even though it remains federal-tax-free.
That's exactly what the "also exempt from state tax" toggle in this calculator controls. Flip it on for an in-state muni and the calculator only grosses up against your federal rate. Leave it off for an out-of-state muni and it grosses up against your combined federal-plus-state rate β which produces a noticeably higher taxable-equivalent yield, because you're comparing against a bigger tax bite that a taxable alternative would also have to clear.
Where Tax-Equivalent Yield Fits in a Bigger Portfolio Decision
TEY is a useful comparison tool, but it isn't the only factor. Municipal bonds generally carry different credit risk profiles, different liquidity, and different interest-rate sensitivity than corporate or Treasury bonds β and munis are typically most useful in a taxable brokerage account, not a tax-advantaged retirement account, since the tax exemption is wasted inside an account that's already tax-deferred or tax-free. Investors sitting in lower tax brackets, or holding bonds inside an IRA or 401(k), usually find taxable bonds a better fit once yield is the only thing being compared, since the tax-exemption advantage simply doesn't apply there.
A Quick Example Walkthrough
Say you're comparing a 3.5% municipal bond issued out-of-state to a corporate bond. You're in the 24% federal bracket and a 5% state bracket, and the muni isn't exempt from state tax. Combined rate: 24% + 5% = 29%. Taxable-equivalent yield: 3.5% Γ· (1 β 0.29) = roughly 4.93%. That means a corporate bond would need to yield about 4.93% before taxes just to match what the 3.5% muni already delivers after tax. If the corporate bond on the table only yields 4.5%, the muni is actually the better after-tax choice, even though its headline yield looks lower at first glance.
Now change one input: suppose that same muni was issued by your home state, making it exempt from state tax too. Combined rate drops to just 24%, and the taxable-equivalent yield falls to about 4.61%. Still higher than the 4.5% corporate bond, but the gap is smaller β which is exactly the kind of shift this calculator is built to show instantly when you toggle the state-exemption setting.
A Note on the Alternative Minimum Tax
Not every municipal bond is entirely tax-free for every investor. Interest from certain "private activity" municipal bonds β often used to fund things like airports, stadiums, or private hospital projects β can be subject to the federal Alternative Minimum Tax (AMT) for investors who owe it. If you're potentially exposed to AMT, it's worth checking whether a specific muni bond is a private activity bond before assuming this calculator's federal-exemption assumption applies in full. Most general obligation munis issued by states and cities for public projects don't carry this AMT wrinkle, but it's a detail worth confirming with your broker or advisor on any large muni purchase.
Arb Digital builds fast, high-converting websites and content for growing businesses β while you're here, run your dividends and capital gains through our other free calculators too.
Try the Dividend Tax Calculator All Free ToolsMunis vs Bond Funds β Does This Math Still Apply?
Everything above works cleanly for an individual municipal bond held to maturity with a fixed, known yield. It gets a little fuzzier for municipal bond mutual funds and ETFs, where the "yield" you see quoted (often an SEC yield or a distribution yield) can shift as the fund buys and sells bonds and as interest rates move. The tax-equivalent yield calculation still applies in principle β you're still grossing up a tax-exempt distribution against what a taxable fund would need to yield β but you should use the fund's actual trailing distribution yield rather than an individual bond's stated coupon, and revisit the comparison periodically since fund yields aren't fixed for the life of your holding the way a single bond's yield is.
Common Mistakes to Avoid
- Comparing a muni's quoted yield directly to a taxable bond's yield without adjusting for taxes.
- Forgetting to include state tax in the comparison for out-of-state municipal bonds.
- Using your average tax rate instead of your marginal rate β TEY should use the rate on your last dollar of income.
- Holding municipal bonds inside a tax-advantaged account, where the tax exemption provides no added benefit.
- Ignoring credit quality and liquidity differences because a muni "wins" on tax-equivalent yield alone.
- Not rechecking the comparison after a tax bracket change from a raise, retirement, or new filing status.
Related Free Tools From Arb Digital
Pair this with the dividend tax calculator for your stock income, the capital gains tax calculator for bond or stock sales, the income tax calculator for your total federal bill, and the tax bracket calculator to confirm your exact marginal rate before running this comparison. Explore everything in our free online tools hub.
Frequently Asked Questions
Tax-equivalent yield is the yield a taxable bond would need to offer to match the after-tax return of a tax-free municipal bond, given your marginal tax rate.
Divide the municipal bond's tax-free yield by (1 minus your combined marginal tax rate). The combined rate includes federal tax, and state tax too if the bond isn't also exempt from state tax.
Most are, but not all β some munis are issued as taxable bonds for specific purposes. Always confirm a bond's tax status before assuming it's exempt.
Because an in-state muni is typically exempt from both federal and state tax, the calculation only needs to gross up against your federal rate, while an out-of-state muni's comparison must account for state tax you'd still owe on a taxable alternative.
Generally no. The tax exemption on municipal bond interest provides no extra benefit inside an already tax-advantaged account like an IRA or 401(k), so munis are usually better suited to taxable brokerage accounts.
Yes. The higher your marginal tax rate, the more valuable a tax exemption becomes, which raises the taxable-equivalent yield for the same municipal bond.
This tool provides general estimates for educational purposes only and is not financial, tax, legal, or medical advice. Figures are illustrative; consult a licensed professional for decisions.
