Bond Price Impact Calculator
See what a rate move does to a bond fund, in money rather than percentages, and how long the higher income takes to make it back.
Bond Price Impact Calculator
The value today, before the rate move.
Years, from the factsheet. Use effective or modified duration, NOT Macaulay, which is the larger of the two numbers the bond pricer below prints. It is the rule of thumb for what a rate move costs: duration 7 means roughly 7% for every one percentage point. A euro government fund was around 7 in July 2026; check your own.
What the fund earns a year if it holds everything to maturity. From the factsheet; around 3.1% for euro government in July 2026.
In basis points. 100 is one percentage point. Positive means rates rise, which pushes prices down.
Advanced options
Leave it at zero for the plain duration rule of thumb, which overstates the fall and stretches the recovery figure. Large moves and long bonds need it; price one bond below to get a real number. A 30-year bond carries roughly 500, a 50-year zero roughly 2,400.
A starting assumption, not your bill. Set it to what you actually pay, or to zero if the income is sheltered. The rate is applied to the whole yield, and after a rate rise part of that yield is the price pulling back towards par rather than cash coupon, so on a discount holding this charges more tax than a coupon-only regime would.
Price one bond from scratch
The annual rate printed on the bond, not what it yields today.
What it repays at maturity.
Priced on a coupon date, with no accrued interest.
The yield the market is asking for this bond today.
It varies by issuer, even between governments: German Bunds pay once a year, Italian BTPs twice. Check the bond.
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That horizon assumes every yield moves once and then sits still, that the fund keeps rolling at the new yield, and that nobody defaults. It measures catching up with where you would have been, not getting back to what you first put in, which happens sooner. It is an estimate, not a date, and a rolling fund never matures, so nothing forces a paper loss to reverse.
The price fall gets no tax relief here: you still own the holding, so nothing has been realised.
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This assumes the income actually reaches you. An accumulating fund rolls it up inside the fund instead, and some countries tax it anyway on a different basis.
A bond fund is not a deposit. It carries no deposit-guarantee cover, and its value can fall.
This is the duration rule of thumb, with convexity as an optional second term. It assumes every yield moves by the same amount, and it says nothing about an issuer failing to pay you back.
Illustrative only: this is an estimate from the numbers you entered, not a forecast and not advice.
Bond and investment values can fall as well as rise.
Actual returns depend on the fund's performance, its charges and where interest rates go next.
What this does
Enter what your bond fund is worth, its duration and yield from the factsheet, and how far you think rates move. It returns the price change in money rather than percentages, and how long the higher income would need to make that back.
How this works
The estimate is the duration rule of thumb: a fund with a duration of 7 falls about 7% when rates rise one percentage point, and rises about as much when they fall. Convexity is an optional second term that corrects the rule of thumb at larger moves, where the straight line overstates a loss and understates a gain. Everything assumes a parallel shift, with every yield along the curve moving by the same amount, and real curves twist. The duration and yield prefills are a euro government bond ETF as at July 2026: a dated snapshot, not live data, so check your own factsheet. The tax rates are starting assumptions taken from each country's own tax authority on 18 August 2026, not your bill: allowances, shelters and bands are not modelled, and the Netherlands taxes what you hold rather than what you are paid. Credit risk is absent throughout, as is any currency move on a non-euro holding. The single-bond pricer values a plain bullet bond on a coupon date, with no accrued interest, no day-count convention and no call features.
This calculator is educational and is not financial advice. It estimates what a change in interest rates would do to a bond holding you describe. Illustrative only: bond and investment values can fall as well as rise, and actual returns depend on the fund's performance, its charges and where interest rates go next. The recovery figure is an estimate of how long higher income would take to catch up with where you would have been had rates not moved, not a date and not a guarantee. Check your fund's own factsheet and your own tax position before acting.