Floating-rate loan calculator

This calculator builds a period-by-period schedule for a loan that pays SOFR plus a fixed margin: accrual dates, actual days, the SOFR assumed for each period, the all-in rate after any floor, and the interest, principal and remaining balance. It is meant for borrowers, credit analysts and treasury teams who need to size debt service on a floating-rate facility, test a floor, or replay how a loan would have behaved through a past rate cycle.

Features

• Real accrual dates, ACT/360Every period runs from one calendar date to the next, and interest is charged on the actual number of days divided by 360, so a 92-day quarter costs more than a 90-day one.
• Floor on SOFR or on the all-in rateChoose where the floor bites. The schedule flags each period in which it raised the rate and counts them in the summary.
• Three amortization stylesLevel principal, interest-only with a balloon, or a level payment re-solved over the remaining term each time the rate resets.
• Four SOFR pathsHold the starting rate flat, ramp it by a fixed number of basis points per reset, type your own path, or replay the New York Fed's published 30-day Average SOFR for a past start date.
• Chart and CSVA step chart of SOFR, the all-in rate and the floor, plus the full schedule as a CSV file for a spreadsheet or credit model.

How to use the floating-rate loan calculator

1. Enter the principal, the first accrual date and the term in months. The term must be a whole number of payment periods, so a quarterly loan needs a multiple of three.
2. Pick the amortization style and enter the margin in basis points and the floor in percent. Set whether the floor applies to SOFR alone or to SOFR plus the margin, as your credit agreement defines it.
3. Choose a SOFR path. The starting SOFR defaults to the latest 30-day Average SOFR; replace it with the rate from your own rate-set notice if you have one.
4. Press Calculate schedule. Read the total interest, check the period rows marked with an asterisk for floor hits, and download the CSV if you need the numbers elsewhere.

How the schedule is calculated

The formulas

Each period has one SOFR value, set at the start of the period, and one all-in rate. Interest is simple interest on the opening balance for the actual days in the period:

Interest and principal are rounded to the cent each period and the balance carries the rounded figures, so the columns add up exactly. Level principal divides the loan evenly across the periods; interest-only pays no principal until the final period. In every style the last period retires whatever balance is left, which is why the final payment can differ from the others.

The effective all-in rate in the summary is total interest × 360 divided by the sum of each period's opening balance × days. It is the single rate that reproduces the total interest, so on an amortizing loan it leans toward the early periods, when the balance is largest, rather than being a simple average of the period rates.

The level-payment option assumes, at each reset, that the new rate will hold for the rest of the term, and solves for the payment that would retire the balance on that assumption. When the rate moves, the payment is solved again. This keeps the loan fully amortizing by maturity whatever SOFR does. A payment fixed at closing would instead leave the effect of every rate change to the final period.

Floors: SOFR or the all-in rate

A floor is a minimum, and the two definitions above give very different results. With a 2.50% margin and a 0.50% floor on SOFR, the all-in rate can never fall below 3.00%. The same 0.50% floor written on the all-in rate would only matter if SOFR fell below −2.00%, so in practice it never binds. The calculator applies the floor to SOFR unless you change the setting, since that is the reading under which a floor changes anything at ordinary margins. If your agreement floors a defined rate that already includes a spread adjustment, enter that adjusted figure as your SOFR.

Floors matter most near zero. SOFR averaged 0.039% across 2021 and never printed above 0.11% that year, so any higher floor was in effect at every reset. The worked example shows what that cost.

Why the projection uses one rate per period

Nobody knows future daily SOFR, so a schedule for future periods needs a simplification. This tool uses the term-style one: each period's rate is fixed at its start and applied to every day of the period. That matches a loan priced off a rate set in advance, such as a 30-day Average SOFR observed on or before the first day of the period, and it lets you write a scenario as a short list of numbers instead of hundreds of daily guesses.

The default starting value is the New York Fed's 30-day Average SOFR, 3.81569% as published October 9, 2026, not the overnight print of 3.87% for October 8, 2026. The average is a compounded rate over the prior 30 calendar days and moves less from day to day. The calculator does not display CME Term SOFR: CME Group requires a license for using its Term SOFR Reference Rates in pricing or in the provision of a service. If your loan references Term SOFR, type the rate from your lender's notice into the starting SOFR field.

The ARRC's 2023 scope-of-use recommendations limited Term SOFR to a short list of uses that included new business loans, while still recommending overnight SOFR and SOFR averages for all products (ARRC, April 2023).

Worked example: a 2022 loan through the hiking cycle

Take a $10,000,000 interest-only loan, quarterly periods starting January 1, 2022, a 250 bp margin and a 0.50% floor on SOFR. Choose the historical path, which uses the latest 30-day Average SOFR published on or before each period start. The first eight quarters come out like this:

Follow the first row by hand: SOFR of 0.04967% is below the 0.50% floor, so the all-in rate is 0.50% + 2.50% = 3.00%, and $10,000,000 × 3.00% × 90 / 360 = $75,000.00. Without the floor the rate would have been 2.54967% and the interest $63,741.75. The floor added $11,258.25 in the first quarter and $8,408.90 in the second, $19,667.15 in all, and stopped mattering at the July 1, 2022 reset. The 30-day average had passed 0.50% on May 19, 2022 (0.51610%), but this loan only saw it at its next reset. Over the eight quarters the loan paid $1,107,506.65 of interest.

The table also shows the lag built into an in-advance rate. The federal funds target range moved up twice inside the third quarter of 2022, effective July 28 (to 2.25%–2.50%) and September 22 (to 3.00%–3.25%), but this loan kept paying on the 1.11248% average it observed on July 1 until the next reset.

How actual in-arrears loans differ

A loan on daily SOFR compounded in arrears does not know its period rate until the period is nearly over. The ARRC's updated user's guide recommended a lookback without an observation shift for business loans, and its loan conventions contemplate a five-business-day lookback (ARRC User's Guide to SOFR, 2021 update). Each day accrues at the SOFR from five business days earlier, compounded across the period.

Run the third quarter of 2022 that way and the period rate is 2.01921%, against the 1.11248% the in-advance loan used. All-in, that is 4.51921% instead of 3.61248%: on $10,000,000 for 92 days, about $23,172 more interest for that one quarter. Plain compounding with no lookback gives 2.13470%. In a falling market the gap runs the other way. You can reproduce these figures with the compounded SOFR calculator or check them against the index with the SOFR Index calculator.

Other things this schedule leaves out: business-day adjustment of period dates, payment delays after the period end, the treatment of a floor inside a daily-compounded rate, fees, and prepayments. For the conventions themselves, see compounding in arrears conventions; for the loan mechanics in general, floating-rate loans on SOFR.

Frequently asked questions

Does a floor apply to SOFR or to the all-in rate?

It depends on the wording of the agreement, and the difference is large. A floor on SOFR guarantees the lender the floor plus the full margin; a floor on the all-in rate at the same level is usually far below the rate the loan would pay anyway. The calculator defaults to a floor on SOFR and lets you switch.

What does "re-solved at each reset" mean for a level payment?

At the start of each period the calculator takes the remaining balance, the number of periods left and the new period rate, and computes the payment that would amortize the balance to zero if that rate held. If SOFR rises, the next payment rises; if it falls, the payment falls. The payment also moves slightly with the number of days in each period, because ACT/360 makes a 31-day month cost more than a 30-day one.

How do I model a rate-cut or rate-hike scenario?

Use the ramp path with a negative or positive change per reset, for example −25 bp per quarter, or type an explicit list in the custom path. A floor keeps the ramp from taking the all-in rate below the minimum.

Can I see how a loan would have performed in the past?

Yes. Choose the historical path and a first accrual date on or after March 2, 2020, the day the New York Fed began publishing the SOFR Averages. Each period uses the latest 30-day Average SOFR published on or before its start date. Periods that start after the latest published value use that value, marked with a dagger in the table.

Why does my lender's interest figure differ from this schedule?

The usual causes are period dates moved to business days, a rate observed a few business days before the period start, compounding in arrears with a lookback, and different rounding. Any of them can move a quarterly interest amount by more than a few dollars on a large loan.

Can the schedule handle a stub period or prepayments?

No. The term must be a whole number of periods, and principal follows the selected style with no voluntary prepayments. To model a prepayment, run the schedule to that date, then start a new one from the reduced balance.

Privacy and data

Every calculation runs in your browser. The 30-day Average SOFR values come from a dated snapshot of New York Fed data served from this site, through October 9, 2026. Nothing you enter is sent anywhere or stored, and the CSV file is generated on your device.