RFR Calculator
Our free risk free rate calculator compounds daily overnight fixings across your exact interest period: SOFR, SONIA, €STR, CORRA, SARON, SORA, TONAR and ZARONIA, with each index's market conventions preset.
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Beyond the realised rate
See where rates are heading next
- Market-implied forward path for 30+ currencies
- Full daily compounded history
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“I do debt service forecasting for any of the facilities where we have floating rate exposure… I like this option to just pull the forward curve monthly or quarterly going out.”
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That's what the last period cost. See what the next one is likely to.
Compounded rates tell you what an interest period has already cost. Forward curves imply the path of future fixings for SOFR, SONIA, €STR, ZARONIA and 25+ more benchmarks, straight from today's market pricing.
Explore forward curvesThis calculator in Excel & API
If you're running this calculation more than once a month, you don't need a calculator, you need a feed. The compounding on this page is one API call, and the published compounded series drop straight into Excel.
// Excel: any day's compounded SOFR in a cell =BlueGamma.FIXING("3M COMPOUNDED SOFR", accrual_date) # API: this exact calculation, one GET away GET api.bluegamma.io/v1/compounded_rate ?index=SOFR&start_date=YYYY-MM-DD &end_date=YYYY-MM-DD&lookback_days=5 x-api-key: your_api_key
FAQs
The calculator compounds daily fixings for eight overnight benchmarks: SOFR (USD), SONIA (GBP), €STR (EUR), CORRA (CAD), SARON (CHF), SORA (SGD), TONAR (JPY) and ZARONIA (ZAR). Selecting an index applies its market conventions automatically, and the advanced settings let you override day count, lookback, lockout and observation shift.
Daily compounded history for each index is on its own page, handy for month-end and quarter-end checks: SOFR, SONIA, €STR, CORRA, SARON and ZARONIA. The daily official prints themselves are on the fixings pages: SOFR fixings, SONIA fixings, €STR fixings, CORRA fixings, SARON fixings and ZARONIA fixings.
Yes. Select SOFR and the calculator applies Actual/360 with a 5 business day lookback, the convention most USD facility agreements use. For the published daily 30, 90, 180 and 360 day averages, see our compounded SOFR page.
Yes. SONIA compounds on an Actual/365 basis; set the lookback to match your facility agreement, with UK loans typically using 5 business days. Daily 1, 3, 6 and 12 month compounded values are on our compounded SONIA page.
Yes. Selecting ZARONIA presets the MPG's recommended loan conventions for South Africa's JIBAR successor: Actual/365 with a 5 business day lookback and no observation shift. Daily compounded ZARONIA values are on our compounded ZARONIA page, and a transition-focused version with SARB conventions preset is on our ZARONIA calculator page.
Yes. Selecting SARON compounds the official daily fixings on an Actual/360 basis with the Zurich business day calendar, the convention Swiss mortgages and CHF facilities use. Unlike the official SIX calculator, there is no three business day delay, no 12 month window and no non-professional restriction. For a SARON-focused version with a worked mortgage example, see our SARON calculator page.
The calculator compounds the official daily fixings in arrears across your dates, applies your day count and lookback settings, and returns the annualised rate plus interest on your notional. The margin is added flat to the compounded reference rate, not compounded with it, following standard LMA and ARRC loan documentation. Because every fixing in the window is already published, the result is the realised cost of the period, not a forecast.
Worked example: take a £10,000,000 drawing from 1 April to 30 June 2026 priced at SONIA plus a 150bp margin, compounding on an Actual/365 basis. Compounding the official Bank of England fixings across the period gives compounded SONIA of 3.74661%. Adding the margin makes the all-in rate 5.24661%, and the interest for the 90 day period comes to £129,368.37. Enter the same dates, notional and spread above and you should reproduce every figure; the daily fixings behind it are on our SONIA fixings page.
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