Tax Equivalent Yield Calculator

How the Tax Equivalent Yield Calculation Works

Tax Equivalent Yield is a financial metric used to compare the yield of a tax-exempt bond (like a municipal bond) with a taxable bond (like a corporate bond or US Treasury). Because municipal bonds are often exempt from federal income tax, their stated yield is essentially their after-tax yield.

To make a fair comparison, we use the following mathematical logic:

Equivalent Taxable Yield = Tax-Exempt Yield / (1 - Marginal Tax Rate)

Strategic Advice for Fixed-Income Investors

Include State Taxes: If you buy a "double-tax-free" bond from your own state, remember to add your state's marginal tax rate to your federal rate for a more accurate comparison.
Consider the Risk Profile: While the yields may be equivalent, the risk is not. Municipal bonds generally have different credit risks than US Treasuries or highly-rated corporate bonds.
Focus on Tax-Advantaged Accounts: Tax-exempt bonds rarely make sense inside a Roth IRA or 401(k), as those accounts are already tax-advantaged. Hold your municipal bonds in taxable brokerage accounts to maximize the benefit.
Watch for the AMT: Some municipal bonds (private activity bonds) may be subject to the Alternative Minimum Tax. Consult with a tax professional if you are subject to the AMT.

Example Scenario: Municipal vs. Corporate

An investor in the 32% marginal tax bracket is choosing between two investments:

Option A: A municipal bond yielding 4.00%.
Option B: A corporate bond yielding 5.50%.

Using the calculator, we find the Tax Equivalent Yield of the municipal bond is 5.88%. Even though the corporate bond's 5.50% looks higher on paper, the municipal bond actually provides a better after-tax return for this investor.

Tax Equivalent Yield FAQ

Why do municipal bonds have lower interest rates?

Because of their tax-exempt status, demand for these bonds is high among investors in high tax brackets. This high demand allows issuers to offer lower interest rates than taxable competitors while still remaining attractive on an after-tax basis.

What is a "Double-Tax-Free" bond?

This refers to a municipal bond that is exempt from both federal and state (and sometimes local) income taxes. This typically occurs when an investor buys a bond issued by a municipality in their own state of residence.

When should I choose taxable bonds instead?

If you are in a low tax bracket (e.g., 10% or 12%), the tax advantage of municipal bonds is often not enough to outweigh the higher nominal rates offered by corporate or treasury bonds. Taxable bonds are also usually superior for funds held within retirement accounts.