EuriborHow Euribor is calculated
Guide · 12-month Euribor · Euribor.site
Two clocks run at once. Clock one is EMMI’s daily 12-month fixing. Clock two is the simple average of those fixings inside a calendar month. Households live on clock two. Markets talk about clock one. Mixing the clocks is the most common unforced error on payment letters.
EMMI’s published method is hybrid. When the market produces enough eligible transactions, those trades dominate. When the tape is thin, the rulebook allows a waterfall of other inputs so the tenor still publishes. The point of the rulebook is robustness, not a casual chat among treasurers.
The monthly average on this site is an arithmetic mean: sum of the 12-month prints dated in that YYYY-MM, divided by the count of those prints. We do not invent a Saturday. We do not carry Friday into Monday. If the daily file has 21 rows for March, March’s mean uses 21 rows.
TARGET holidays punch holes in the month. A short February is not an error. A month with 19 prints is still a valid average if those 19 days are all the business days that existed.
Until the last business day is in, the month-to-date figure is provisional. It will move when the next print arrives. That is why the home page labels it “until [date]” and shows how many fixings sit in the mean.
What a contract usually does with that mean
Typical euro-area floating loan: coupon = monthly 12-month average of the reference month + contractual spread, maybe rounded to three decimals, maybe with a floor. The reference month is often “the month before the review month.” Read the clause. Do not assume our dashboard chose your month.
The monthly average tool rebuilds the mean from whatever daily rows exist for a YYYY-MM. If you type a month the daily file does not cover, the tool says so instead of interpolating.
Closed months live in the monthly JSON that starts in January 1999. That file is what the long chart uses. Daily JSON is a shorter rolling window of recent sessions. Do not expect 2008 daily ticks in the daily file.
Rounding, floors and lookbacks
Three decimal places are the usual display. Some facilities round the sum of index plus margin, not the index alone. A floor at zero was common after the negative years. None of that is visible in a raw Euribor print. It lives in the contract.
Lookback (using last month, two months back, or a gazette date) is also contractual. National gazettes may republish a monthly average days after month-end. The economic number can match our table while the legal citation is a later PDF.
Methodology papers: EMMI. Live prints: today. Year-ago change of closed months: this tool.
Practical order when a letter arrives: identify tenor, identify month, copy the average from the monthly table, add spread, apply floor/rounding, then compare with the letter. Only after that gap is real should you call the lender. Calling first with “Euribor today is X” wastes everyone’s Tuesday.
If two co-borrowers argue from two different screens — one showing a daily print, one showing last month’s mean — they are not disagreeing about the market. They are holding two clocks. Put both numbers on one scrap of paper and the argument usually shrinks.
Next reads: who publishes, forecasts versus fixings.
Field guide: checking a reset letter in fifteen minutes
Photograph the clause that names the index, the tenor and the reference month. Do not trust memory.
Open the monthly table on this site or the history page. Find that YYYY-MM. Copy the average to three decimals.
Add the spread from the same clause. Apply floor or rounding if written.
Drop principal, years and that all-in rate into the loan-impact tool. Compare the payment with the letter.
Only a real gap deserves a call. A gap of a few cents can be day-count. A gap of tens of euros is a different month or tenor.
Keep the five screenshots in one folder named with the review date. Next year you will thank yourself instead of re-learning the clause under time pressure.
If you rebuild the month by hand, watch the count of days. Dividing by 30 when the file has 21 prints is how homemade averages go strange. Divide by the count of prints, not by the count of calendar squares.
Mid-month curiosity is fine. Mid-month panic is optional. The provisional mean is allowed to move until the month closes. Save the drama for the closed print if the deed uses a closed month.
Two reviewers in one household should use the same month. Mixing “this morning” with “last July” is not a compromise. It is two problems stacked.
The hybrid daily method can feel opaque. You are not required to audit panel submissions to live with a mortgage. You are required to know whether your letter used a daily print or a monthly mean. That single fork explains most “the website is wrong” emails.
Algebra reminder: average first, then add spread, unless the deed literally says the opposite. People add spread to each day and then average. That can match, but if rounding happens per day it will not. Follow the written order.
Keep a paper strip next to the screen: tenor, month, average, spread, payment. Every extra tab you open without filling that strip is entertainment. Fill the strip first, then read commentary. The strip is the product; the commentary is optional.
When in doubt, open the history chart from January 1999 and sit with it for a minute. Long context lowers the temperature of any single print, including the one in the hero box today.
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