Tax Equivalent Yield Calculator
Compare tax-exempt municipal bond yields to taxable bond yields.
What this calculator does
This calculator answers whether a tax-free yield beats a taxable one for you specifically. It takes a tax-exempt yield and your marginal tax rate and returns the tax-equivalent yield — the pre-tax return a taxable investment would need to deliver the same money after the IRS takes its share.
The reason the answer is personal is that the same municipal bond is a good deal at 37 percent and a poor one at 12 percent. Headline yields cannot be compared directly across tax-free and taxable investments, and the tax-equivalent yield is the conversion that makes them comparable.
When to use it
Use it whenever you are choosing between a municipal bond or muni fund and a taxable alternative — corporate bonds, Treasuries, CDs, or a high-yield savings account. Municipal yields look unattractive on the surface precisely because they are quoted after their main advantage has already been applied.
It is also the right check at the start of a new tax year or after a change in income. Moving from the 24 percent bracket to 32 or 35 can flip the answer without either yield moving. And it is worth running before putting bonds in a taxable account at all, since asset location — which account holds which asset — is often worth more than the security selection itself.
Understanding the inputs
The tax-exempt yield is the stated yield on the municipal bond or fund. For a fund, use the SEC 30-day yield rather than the distribution yield, and net out the expense ratio, otherwise you compare a gross figure against a net one.
The marginal tax rate is your top federal bracket — the rate applied to your next dollar of income, not the effective rate across your whole return. Add your state marginal rate if the bond is issued in your state of residence and therefore exempt from state tax as well. High earners should also consider the 3.8 percent net investment income tax, which municipal interest escapes but taxable interest does not.
How is this calculated?
Tax-equivalent yield = tax-free yield / (1 - combined marginal tax rate). It answers what a taxable bond would need to yield to leave you with the same after-tax income as a tax-exempt municipal bond. Because the divisor depends on your bracket, the same municipal bond is worth more to a higher-rate taxpayer.
A worked example
Suppose you are in the 32 percent federal bracket, comparing a 3.5 percent municipal bond against a 5 percent corporate bond of similar quality and maturity. The muni's tax-equivalent yield is 3.5 divided by 0.68, or about 5.15 percent. The muni wins, though only by 15 basis points.
Change the bracket and the answer flips. At 24 percent, the tax-equivalent yield falls to about 4.61 percent and the corporate bond is clearly better. Move up to the 37 percent bracket with a 5 percent state tax on top, and an in-state muni's tax-equivalent yield rises to roughly 6.03 percent — a full point of advantage over the corporate bond.
Limitations and assumptions
This is a yield comparison, not a risk comparison. It says nothing about credit quality, duration, call provisions, or liquidity, and a muni with a tempting tax-equivalent yield may simply be a riskier bond. Only compare securities of similar rating and maturity.
It also assumes your marginal rate stays where it is, which retirement, a bonus, or a change in tax law can all undo. Municipal interest is not always fully exempt — private activity bonds can trigger AMT, capital gains on sale are taxable, and muni interest counts toward the provisional income test for Social Security. For a large allocation, confirm the treatment with a tax professional rather than a yield calculation.
Common Questions
- What does tax-equivalent yield tell me?
- It converts a tax-free yield into the taxable yield you would need to earn the same after-tax income. A 3.5 percent municipal bond in the 32 percent bracket has a tax-equivalent yield of about 5.15 percent, which means any taxable bond paying less than 5.15 percent leaves you worse off.
- What is the formula?
- Tax-equivalent yield equals the tax-exempt yield divided by one minus your marginal tax rate. The marginal rate is the one on your next dollar of income, not your effective rate across all income. Using your effective rate — usually several points lower — will understate the advantage of the tax-free bond.
- Should I include state taxes?
- Yes, when they apply. A municipal bond issued by your own state is typically exempt from both federal and state tax, so use your combined marginal rate. At 37 percent federal plus 5 percent state, a 3.5 percent in-state muni has a tax-equivalent yield above 6 percent. Out-of-state munis are usually federally exempt only.
- At what tax bracket do munis start making sense?
- Broadly, the 32 percent bracket and above, though it depends on the spread between muni and corporate yields at the time. In the 12 or 22 percent brackets, taxable bonds and CDs usually win outright. Run the numbers rather than relying on the rule — the crossover moves with market conditions.
- Are municipal bonds completely tax-free?
- Not always. Interest is generally exempt from federal tax, but capital gains from selling a muni above your cost basis are taxable, and some private activity bonds are subject to the alternative minimum tax. Muni interest also counts toward the provisional income calculation that determines how much of your Social Security is taxable.
- Does this apply to Treasuries?
- Partly, in reverse. Treasury interest is taxable federally but exempt from state and local tax. If you live in a high-tax state, a Treasury's yield is worth more than an identical corporate bond or CD yield. Enter just your state marginal rate to see the size of that advantage.
- Should I hold munis in an IRA or 401(k)?
- No. Those accounts are already tax-sheltered, so a tax-free yield buys you nothing and you give up the higher taxable yield for no benefit. The standard placement rule is munis in taxable accounts, taxable bonds and REITs in tax-deferred accounts, and equities wherever there is space left.
- Does a higher tax-equivalent yield mean a better investment?
- Only on the tax dimension. Credit quality, duration, call features, and liquidity all still apply. A high-yield muni from a distressed issuer can show an attractive tax-equivalent yield and carry genuine default risk. Compare tax-equivalent yields only between bonds of similar credit rating and maturity.
- How do muni bond funds compare to individual bonds?
- A fund gives you diversification across hundreds of issuers and daily liquidity, at the cost of an expense ratio and no fixed maturity date, so your principal fluctuates with rates. Subtract the fund's expense ratio from its distribution yield before running the tax-equivalent calculation, or you will overstate the benefit.