How this instrument works
This instrument takes the same four figures a bond screener usually lists — face value, market price, coupon rate as a percentage, and years remaining — and returns two different yields from them at once rather than one. Most yield tools ask for the coupon in dollars and answer a single question; this one accepts the rate the way it is actually quoted on a listing, converts it internally, and puts current yield next to approximate yield to maturity so the two can be compared without reaching for a second page.
The two outputs answer different questions with the same inputs. Current yield is coupon income divided by what you pay today — it has no memory of face value and no view of the future. Approximate yield to maturity starts from that same coupon but adds a second term: the gap between price and face value, spread evenly across the years left, standing in for the gain or loss locked in at maturity. A bond bought under par earns that gap as a bonus on top of its coupon; a bond bought over par gives some of its coupon back to close the gap. Current yield never sees either effect, which is exactly why the two figures diverge.
Investors building a bond ladder from a list of secondary-market issues, each quoted by coupon percentage rather than dollar amount, use a side-by-side reading like this to rank candidates quickly before opening a full pricing calculator on the ones worth a closer look. The approximate yield to maturity trades precision for a formula solvable without iteration — it spreads the price gap evenly rather than compounding it, treats coupons as annual, and ignores what happens to reinvested coupon cash. The wider a bond sits from par or the more years left on the clock, the more this shortcut and the true, iteratively solved yield to maturity part ways.
- Enter the bond's Face value, $ — the sum the issuer hands back when it matures, commonly $1,000 for a standard issue.
- Enter Current market price, $ — the price quoted for the bond right now, which can sit above or below that face value.
- Set Annual coupon rate, % — the rate printed on the bond, not a dollar figure; the instrument multiplies it by face value for you.
- Set Years to maturity — the count of years left before the bond is redeemed at face value.
- Read Current yield, % and Approximate yield to maturity, % together — the gap between them is the price-to-par adjustment the second formula adds.
Worked example — a 5% coupon bond priced at $950
Set Face value, $ to 1,000, Current market price, $ to 950, Annual coupon rate, % to 5, and Years to maturity to 10. The coupon rate converts to a $50 annual payment, five percent of the $1,000 face value. Current yield is that $50 divided by the $950 price, times 100, which comes out to 5.263% — the income this bond hands back each year measured against what it costs to buy right now.
Approximate yield to maturity starts from the same $50 coupon and adds the gap between price and face value: $1,000 minus $950 is $50, spread over 10 years is $5 a year, for a blended $55. Averaging face value and price gives $975; dividing $55 into that and scaling by 100 lands on 5.641%. The two figures sit roughly 0.38 percentage points apart — current yield shows the coupon alone, while approximate yield to maturity credits the built-in climb back to par that current yield cannot see.
Questions
Why do current yield and approximate yield to maturity show different numbers for the same bond?
Current yield only weighs the coupon against today's price, so it never notices that a discount bond climbs back to face value at maturity. Approximate yield to maturity adds that climb, spread evenly across the years remaining, on top of the coupon. For a bond bought under par the second figure always comes out higher; for one bought over par it always comes out lower; the two meet only when price equals face value.
Why does this calculator ask for a coupon rate instead of a dollar coupon amount?
Because that is how most bond listings and screeners quote a bond — as a percentage of face value, not a raw dollar figure. Typing 5 for a 5% coupon skips a manual multiplication step; the instrument multiplies Annual coupon rate, % by Face value, $ internally to get the dollar coupon both formulas need.
What does a wide gap between the two yields usually mean?
A wide gap points to a bond trading well away from its face value, at either a steep discount or a rich premium. Years to maturity matters too: the same dollar gap between price and face value gets divided across fewer years for a bond nearing maturity, so a short-dated bond can post a wider gap than a long-dated one carrying the identical discount.
Can this instrument be used for a bond priced above face value?
Yes. Enter a Current market price, $ higher than Face value, $ and approximate yield to maturity comes out below current yield instead of above it, because the price-to-par term turns negative — the premium paid today is set to be given back by maturity, and the formula subtracts that loss from the coupon rather than adding a gain.
Does the approximate yield to maturity match what a brokerage statement shows?
Not exactly. This is a widely used shortcut that spreads the price-to-par gap evenly across the remaining years instead of compounding it, so it lands close to the true, iteratively solved yield for a bond near par with just a handful of years left, and pulls further away for one sitting well off face value or running a long stretch to maturity. Treat it as a fast screening figure, not a settlement-grade one.
Does either formula account for coupons paid twice a year?
No — both assume a single annual coupon. A large share of real-world issues, Treasury notes and corporate bonds among them, actually split that same yearly amount into two semiannual payments instead. That split does not change the Annual coupon rate, % entered here, but the true cash-flow timing differs from what these two formulas assume, one reason the approximate yield to maturity stays a screening estimate rather than an exact one.
References
- SEC Investor.gov — Bonds or fixed income products
- Federal Reserve — Selected interest rates (H.15 release)
Read this first: This instrument shows arithmetic, not advice. Real offers add fees, taxes and terms that vary by lender and place — verify the figures against your actual paperwork before deciding anything.