The formula
How to calculate bond yield
Current yield is the annual interest a bond pays as a percentage of what you would pay for it today. Because bonds trade away from face value, the coupon rate printed on the bond and the yield an actual buyer receives are rarely the same.
The coupon is fixed against face value and never changes. The price does, so a bond bought below par yields more than its coupon rate and one bought above par yields less.
What to enter:
- Face value — the amount repaid at maturity, usually 100 or 1,000
- Coupon rate (%) — the annual interest as a percentage of face value
- Market price
No submit button: type and the answer moves. Your inputs end up in the link, so the page can be shared already filled in.
Some of the fields above will accept figures that seem unusual for your own situation, and that is deliberate: the formula behind bond yield works the same way regardless of scale, so the calculator does not stop you testing a hypothetical scenario a long way from your actual numbers — often the fastest way to see which input the result is most sensitive to.
Why bond yield matters
Most people who look up a bond yield calculation already have a specific number in mind — a quote, an offer, a target — and want to check it rather than learn the theory behind it. This page is built for that: enter your own figures, see the result immediately, and change any field to see how the answer moves without redoing the arithmetic from scratch each time.
This tends to come up when comparing two concrete alternatives — two lenders, two savings products, two ways of structuring the same decision — rather than in the abstract. Run both scenarios through the same calculator with the same assumptions and the comparison becomes fair, because the only thing changing between the two results is the number you are actually trying to test.
It is also worth being clear about what a single figure like this can and cannot settle on its own. It answers the specific question the formula was built to answer, and nothing more — a favourable bond yield result does not automatically mean a decision is a good one overall, since plenty of other factors that a formula cannot capture, from personal circumstances to how comfortable a commitment feels, usually matter just as much as the arithmetic. Use the number as one solid input among several rather than the whole of the decision.
Where the same calculation needs to be run for several different scenarios side by side — three loan offers, two savings plans — the fastest approach is usually to open the calculator in a second browser tab for each one, so that the results can be compared directly rather than overwriting each other in a single set of fields.
Worked example
Work through the defaults on this page:
- Face value: 1,000
- Coupon rate: 4.5 %
- Market price: 920
That gives:
- Current yield: 4.891 %
- Annual coupon payment: 45
- Discount to face value: 8 %
These figures are only the calculator's own starting values, included so the working is visible rather than hidden inside the tool above. Replace them with your own numbers and the same arithmetic applies — nothing about the method changes, only the inputs feeding it.
Reading the result
Current yield only counts the income. It ignores the gain or loss when the bond matures at face value — worth £80 per bond in the example above. Yield to maturity is the measure that includes it.
Where this goes wrong. Reading a high current yield as a bargain. Prices fall for a reason: either market rates rose, which affects everything, or the issuer's credit deteriorated, which affects the odds of being repaid at all.
A useful check on any unfamiliar result is to compare it against a rough mental estimate first — round the inputs to convenient numbers and see whether the calculator's answer lands in roughly the same territory. A wildly different figure usually means one of the fields was entered in the wrong unit, most often a percentage typed as a whole number where a decimal was expected, or the reverse.
Because a bond paying a fixed 4.5% has to compete with new bonds paying more. The only way an old bond becomes competitive is for its price to drop until the return matches.
Current yield counts only the coupon income against today's price. Yield to maturity also includes the pull towards face value as the bond approaches redemption, so it is the fuller measure of total return.
The answer it gives you is current yield. With 1,000 face value, 4.5 % coupon rate and 920 market price, that comes to 4.891 %. Change any field and the figure moves with it.
Whenever one of the underlying figures changes — a new interest rate, a different balance, an updated term — since the result only reflects what is currently in the fields. There is no need to keep a separate record of past results; the web address for a filled-in version already carries the figures used to produce it.
Not unless a tax rate or a fee is explicitly one of the inputs above. Where it is not, the figure shown is a gross calculation, and any tax due depends on your personal circumstances and current tax rules, which are worth checking separately.
The arithmetic itself is exact — the calculator applies the formula shown above precisely, with no rounding until the final figure is displayed. The uncertainty, where it exists, is entirely in the inputs: an estimated rate or an approximate balance carries that same approximation through to the result.