The ceiling, the floor, and the gap
Every published refinance range hides three numbers: the floor that gets advertised, the ceiling that gets buried, and the gap in dollars between them. On $30,000 over 10 years, SoFi's fixed range is a $13,138 gap (checked 2026-08-25).
What are the three numbers behind an advertised rate?
The floor, the ceiling, and the gap. A lender's rates page publishes a range, such as SoFi's fixed range of 3.99% to 10.99% (checked 2026-08-25). The low end is the floor, the number that gets printed as "as low as." The high end is the ceiling, the rate a borrower gets if the lender prices them at the top.
The gap is my own term, and it is not on any rates page. It is the interest over the life of the loan at the ceiling, minus the interest at the floor, for a fixed balance and term. Everything on the lender list uses one reference case: $30,000 over 10 years, repaid monthly. No fees are added, because no lender in the dataset states a non-zero origination fee (checked 2026-08-25).
Why does the ceiling matter more than the floor?
Because the floor is the best case and the ceiling is the worst case, and a borrower does not choose between them. The lender does, after reading the application. The floor is what the lender is willing to offer someone. The ceiling is what it is willing to charge you.
The two ends are far apart in dollars. Across the 24 computable products, the gap on $30,000 over 10 years runs from $3,518 to $14,443, with a median of $9,658 (checked 2026-08-25). That spread is the reason what refinancing costs is written around the ceiling rather than the advertised rate.
What does the gap look like in dollars?
On SoFi's fixed product, $13,138 (checked 2026-08-25). SoFi publishes a fixed range of 3.99% to 10.99% with autopay, and its page states the range already includes the 0.25% autopay discount (checked 2026-08-25). Here is the arithmetic for $30,000 over 10 years, using the monthly payments from the site's build.
The monthly payment moves from $303.59 at the floor to $413.08 at the ceiling (checked 2026-08-25). The interest over the life of the loan moves from $6,431 to $19,570 (checked 2026-08-25). A reader who only sees "as low as 3.99%" sees none of that.
If your balance or term is different, the calculator redoes the same arithmetic with your numbers and shows both ends of the range side by side.
How do five lenders compare on the same $30,000?
Brazos has the smallest gap of the five below, at $3,518, and Navy Federal Credit Union the largest, at $14,443 (checked 2026-08-25). The table uses fixed products only, so the ceiling is a fixed rate and not a variable one that could move later.
| Lender (fixed) | Published range | Interest at floor | Interest at ceiling | Gap |
|---|---|---|---|---|
| Brazos | 3.99% to 5.99% | $6,431 | $9,949 | $3,518 |
| RISLA | 3.49% to 7.64% | $5,582 | $12,996 | $7,414 |
| LendKey | 3.98% to 9.24% | $6,414 | $16,072 | $9,658 |
| SoFi | 3.99% to 10.99% | $6,431 | $19,570 | $13,138 |
| Navy Federal Credit Union | 4.20% to 11.80% | $6,791 | $21,234 | $14,443 |
^ Source: each lender's own rates page as listed in Method; interest computed on $30,000 over 10 years; ranges for Brazos, RISLA, LendKey, SoFi, and Navy Federal Credit Union are stated with autopay (checked 2026-08-25).
Notice what the floor column does. Brazos, SoFi, and LendKey sit within a few dollars of each other at the floor: $6,431, $6,431, and $6,414 (checked 2026-08-25). Sorted by the advertised rate, those three look interchangeable. Sorted by the ceiling, they separate: Brazos' worst case is $9,949 of interest and SoFi's is $19,570 on the same balance (checked 2026-08-25).
There is a catch in the Brazos row, and I have left it in on purpose. Brazos is a Texas-focused nonprofit, and its 5.99% ceiling comes from a rate chart showing three fixed APRs rather than a stated top of range (checked 2026-08-25). RISLA states its range in full and caps its balance at $250,000 (checked 2026-08-25). Read RISLA's page and Brazos' page for the conditions before treating either ceiling as yours.
Why does this site sort by the ceiling?
Because the ceiling is the only end of the range a lender promises not to exceed. The floor is a rate some borrowers get. The ceiling is a rate no borrower on that product gets more than, unless the product is variable and the rate resets. Sorting by the number a lender cannot go above is sorting by the number you can hold the lender to.
It also removes the incentive to print a tiny floor. Yrefy publishes a fixed range of 0.10% to 5.99% (checked 2026-08-25). Sorted by floor, it would sit above every other product on the list. Sorted by ceiling, it ties with Brazos at $9,949 of interest on $30,000 over 10 years, (checked 2026-08-25). Read its row with its page: Yrefy refinances private student loans, including distressed ones, and states that its rates "aren't determined by your credit score" (checked 2026-08-25), so it is a different product from the others on the list. The full ordering is in the $30,000 table, and the reasons behind it are in Method.
Three products cannot be sorted this way at all. Earnest, ELFI, and Advantage Education Loan publish a floor only, with no ceiling, so they have no gap to compute (checked 2026-08-25). They appear on the list marked as floor-only rather than being ranked on a number they did not publish. The floor-only problem gets its own treatment in why a rate with no ceiling is not a rate.
What the gap does not tell you
It does not tell you where in the range you will land. Nothing on a rates page does, and I do not publish approval odds or credit-score thresholds because the lenders do not publish them either. The gap tells you how much is at stake between the best and worst case, which is a different question from which case is yours.
It also does not include the discount conditions. Citizens, for example, states a reduction of up to 0.50 percentage points for loyalty and automatic payment (checked 2026-08-25). Its page does not say whether the published range of 5.90% to 10.65% already includes it (checked 2026-08-25). Eight of the 24 computable products leave the autopay basis unstated in the same way (checked 2026-08-25). How those conditions change the arithmetic is covered in what "with autopay" changes in the numbers.
Where the answer changes
- If your balance is $10,000 rather than $30,000, the gap shrinks with it. SoFi's fixed gap over 10 years is $4,379 on $10,000 and $13,138 on $30,000 (checked 2026-08-25).
- If your term is 20 years rather than 10, the gap more than doubles. SoFi's fixed gap on $30,000 is $13,138 over 10 years and $30,676 over 20 years (checked 2026-08-25).
- Do not decide yet if the only number you hold is the published range. Until a written quote is in hand, budget at the ceiling, which is $413.08 a month on $30,000 over 10 years for SoFi's fixed product (checked 2026-08-25). For SoFi's fixed product that ceiling is 10.99% (checked 2026-08-25). Until a quote is in hand, the gap is the size of your uncertainty, not your cost.
Who this article is not for
If you already hold a written rate quote from a lender, the ceiling and the floor no longer matter to you, because you have a single number. Take that number to the calculator instead. This article is for the reader who is still comparing rates pages and has only the published range to go on. It is also not for anyone considering refinancing federal loans. Refinancing them privately gives up federal repayment options, and studentaid.gov is the place to check that first.
Sources
- SoFi rates page, https://www.sofi.com/refinance-student-loan/refinance-student-loan-rates/, checked 2026-08-25
- Brazos refinance page, https://studentloans.com/student-loan-refinance/, checked 2026-08-25
- RISLA refinance page, https://www.risla.com/refinance, checked 2026-08-25
- LendKey refinance page, https://www.lendkey.com/student-loan-refinancing/, checked 2026-08-25
- Navy Federal Credit Union rates and terms, https://www.navyfederal.org/loans-cards/student-loans/resources/refinance-rates-and-terms.html, checked 2026-08-25
- Yrefy refinance page, https://yrefy.com/student-loan-refinance, checked 2026-08-25
- Citizens refinance page, https://www.citizensbank.com/student-loans/student-loan-refinance.aspx, checked 2026-08-25
- Earnest refinance page, https://www.earnest.com/refinance-student-loans, checked 2026-08-25
- Over the Life dataset and computed figures (data/dataset.json, data/computed_for_articles.json), checked 2026-08-25
How this article was made. Written by Kaz, an independent publisher. All figures come from the companies' own published documentation or regulator publications; each figure carries the date it was last checked. I have not borrowed from these lenders, and nothing here is a personal result. The arithmetic is shown so you can recalculate with your own numbers. Found an error? Use the contact form; corrections are logged on the Editorial policy page.
Related articles
- Why the advertised rate is the bottom of the range
- What the advertised rate leaves out
- Reading the interest at the ceiling column
Written by Kaz (pen name). Figures are copied from the sources' published pages on the dates shown. We have not used these products. Corrections: contact form.