Bond Yield Calculator

Estimate coupon yield, current yield, yield to maturity, and bond price scenarios.

Bond inputs

Estimate current yield, approximate yield to maturity, after-tax yield, and duration.

Approx. YTM

5.86%

Current yield

5.26%

After-tax YTM

5.09%

Annual coupon

$50

Total coupon income

$350

Capital gain/loss

+$50

Approx. duration

5.96 years

Rate +1% price impact

-5.96%

Duration-based estimate.

Approximate YTM uses the common shortcut formula. Use a market-grade bond desk or spreadsheet solver for exact settlement-date pricing.

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What is the bond yield calculator?

This calculator estimates yield to maturity, current yield, after-tax yield, duration, convexity, and credit-risk interpretation for Korean government bonds, corporate bonds, local-government bonds, and special bonds.

Yield formulas

YTM and current yield

  • Yield to maturity is the annualized return if a bond is bought at the current price and held until maturity, including coupon income and capital gain or loss.
  • Bond price = sum(coupon / (1 + YTM)^t) + face value / (1 + YTM)^n.
  • The calculator solves this equation numerically, similar to the Newton-Raphson approach described in the Korean source.
  • Current yield = annual interest / current bond price x 100. It is simpler than YTM because it ignores capital gain and loss.

Tax and financial-income aggregation

  • In 2026, Korean bond interest income tax is 15.4%, composed of 14% income tax and 1.4% local income tax.
  • After-tax YTM = YTM x (1 - 0.154) in the simplified guide formula.
  • If annual financial income exceeds KRW 20,000,000, comprehensive financial-income taxation may apply and the marginal tax rate can be higher.
  • Bond trading gains are described as currently non-taxable in the Korean source, while interest is withheld.

Duration, convexity, and credit risk

Interest-rate sensitivity

  • Macaulay duration is the weighted average period to recover bond cash flows. For a zero-coupon bond, duration equals maturity.
  • Modified duration estimates price sensitivity: if duration is 5, a 1% rate rise lowers price by about 5%, and a 1% rate fall raises price by about 5%.
  • Convexity captures the curved price-yield relationship. Higher convexity means larger upside when rates fall and smaller downside when rates rise.

Bond types and strategies

  • Korean government bonds are treated as AAA and the safest benchmark; corporate bonds range from AAA to BBB investment grade and below BB speculative grade.
  • Laddering spreads maturities across 1, 3, 5, and 10 years to reduce reinvestment risk.
  • Barbell strategy uses short and long bonds; bullet strategy concentrates on a target maturity; immunization matches investment horizon and duration.
  • A high YTM is not automatically attractive because it can reflect credit risk, downgrade risk, or liquidity risk.