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ARM Payment Jump Calculator
Before taking a DSCR ARM, see your exact payment at first adjustment and worst case — including how each scenario affects your DSCR tier.
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ARM inputs
Enter your ARM details
Loan structure
Rate during initial fixed period
e.g. 5 for a 5/1 ARM
Index & caps
Current 30-day SOFR
Typical: 2.5–3.0%
Max rate change at first adjustment
Max change per subsequent adjustment
Max total increase over start rate
DSCR inputs (optional)
Payment analysis
Fully-indexed rate at first adjustment: 7.250% (SOFR 4.5% + margin 2.75%)
- Initial P&I (fixed period)
- $2,270.09
- P&I at first adjustment
- $2,374.89
- Payment jump at first adj.
- $104.80
- Worst-case adj. rate
- 8.750%
- Worst-case P&I payment
- $2,701.28
- Worst-case payment jump
- $431.18
DSCR comparison
- DSCR at initial rate
- 1.04
- DSCR at first adjustment
- 1.00
- DSCR at worst case
- 0.89
ARM caps limit how much your rate can increase. The initial cap controls the first adjustment; the periodic cap applies each subsequent adjustment; the lifetime cap is the maximum total increase from your starting rate. Worst-case scenario assumes the initial cap is hit at the first adjustment.
Compare ARM vs fixed rate quotes
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How DSCR ARMs work
An adjustable-rate DSCR loan has two distinct phases. During the fixed period (typically 5, 7, or 10 years), the rate is locked and your P&I payment is predictable. After the fixed period, the rate resets annually based on:
Adjusted rate = SOFR index + lender margin (subject to caps)
The key risk is that SOFR can rise significantly between when you close and when your first adjustment hits. From 2021 to 2023, SOFR moved from near zero to over 5% — a 500 basis point swing. An investor who took a DSCR 5/1 ARM in 2019 at 5.50% faced an adjusted rate of 7.25–8.00% at the 2024 reset, well above what they underwrote.
Understanding the cap structure
ARM caps limit — but don't eliminate — payment risk. A common DSCR ARM cap structure is 2/2/5:
- 2 = the rate can't move more than 2% at the first adjustment
- 2 = the rate can't move more than 2% at any subsequent annual adjustment
- 5 = the rate can never be more than 5% above or below the starting rate over the life of the loan
If your starting rate is 6.50% with a 2/2/5 cap structure, the worst-case first adjustment is 8.50% (6.50% + 2%). The absolute worst case over the full life is 11.50% (6.50% + 5% lifetime cap). Each of these has a materially different payment — the calculator models both.
DSCR impact of payment jumps
The DSCR impact of a rate adjustment depends on how far P&I moves and how much cushion your initial DSCR had. Examples at $350,000 loan, $2,800/mo rent, $700/mo TIHA:
| Scenario | Rate | P&I | PITIA | DSCR |
|---|---|---|---|---|
| Fixed period | 6.50% | $2,212 | $2,912 | 0.96 |
| First adjustment | 8.50% | $2,629 | $3,329 | 0.84 |
| Worst case | 11.50% | $3,344 | $4,044 | 0.69 |
In this example, the deal starts below 1.00 DSCR already — a known risk going in. The worst-case pushes DSCR below 0.75, where lender options are severely limited for a refi. If you're taking an ARM with a tight initial DSCR, stress-test the worst case before you close.
When a DSCR ARM makes sense
ARMs can be the right tool in specific situations:
- Short-term hold (under 5 years): If you plan to sell before the fixed period expires, the lower initial rate saves cash without incurring adjustment risk.
- Bridge to lower fixed rates: In a high-rate environment, an ARM may bridge to a period when rates fall and you can refi to a fixed rate more cheaply than waiting.
- DSCR-boosting structure: On a deal where initial DSCR is tight, the ARM's lower starting rate may clear the 1.00 threshold that a fixed rate can't. The calculation must include a full stress-test of the worst-case scenario.
Fixed vs ARM: the DSCR investor's framework
Most experienced DSCR investors apply a simple framework: if the fixed-rate DSCR is acceptable, take the fixed rate. The certainty of a 30-year fixed mortgage is worth the small rate premium for long-term hold properties. ARMs are a tactical tool — useful in specific scenarios — not a default choice.
Next steps
- Compare fixed vs ARM payments with the Mortgage Payment + DSCR calculator.
- If you already have an ARM, check your refi economics with the Refi Break-Even calculator.
- Get current ARM and fixed quotes from multiple DSCR lenders to see the actual spread.
Frequently asked questions
What is an ARM on a DSCR loan?
An Adjustable-Rate Mortgage (ARM) on a DSCR loan has a fixed rate for an initial period (commonly 5, 7, or 10 years), then adjusts periodically based on a market index (typically SOFR) plus a lender margin. A DSCR 5/1 ARM is fixed for 5 years, then adjusts annually. ARMs offer lower initial rates but carry payment risk if rates rise at adjustment.
What is SOFR and how does it affect my ARM rate?
SOFR (Secured Overnight Financing Rate) replaced LIBOR as the primary benchmark for adjustable-rate mortgages in the US. Your ARM rate at adjustment = current SOFR + lender margin. If SOFR is 4.5% and the margin is 2.75%, your fully-indexed rate is 7.25%. Caps then limit how far above or below your starting rate the adjusted rate can land.
What do the ARM caps mean (initial, periodic, lifetime)?
The initial cap limits how much the rate can change at the very first adjustment — typically 2% or 5% above the starting rate. The periodic cap limits each subsequent annual adjustment — usually 2%. The lifetime cap is the maximum the rate can ever increase above your original rate — typically 5–6%. A 5/2/5 ARM means: initial 5%, periodic 2%, lifetime 5%.
What is the worst-case payment on a DSCR ARM?
The worst-case scenario assumes the rate hits its initial cap at the first adjustment and continues to the lifetime cap over subsequent years. The calculator shows your payment at first adjustment (capped by the initial cap) and at the lifetime worst-case. Both are calculated on the remaining loan balance at the adjustment date, which is lower than the original principal — so worst-case is not as dramatic as applying the worst rate to the original balance.
Does a DSCR ARM make sense for investment properties?
It depends on your hold strategy. If you plan to sell within 5–7 years, a 5/1 or 7/1 ARM can save $100–$200/month during the fixed period. If you're a long-term buy-and-hold investor, a fixed rate eliminates payment uncertainty and simplifies cash flow modeling. Most DSCR investors with a 5+ year hold prefer fixed rates for the predictability, especially since DSCR loan rates are already higher than owner-occupied rates.
How does the ARM payment jump affect DSCR?
When your rate adjusts upward, P&I increases, which increases PITIA, which reduces DSCR. If your deal is currently DSCR 1.15 on the fixed ARM rate and the worst-case adjustment adds $250/month to P&I, DSCR might drop to 0.98 — below the break-even tier. The calculator shows DSCR at each scenario so you can see the risk to your cash flow tier.
What's a typical margin on a DSCR ARM?
Lender margins on DSCR ARMs typically run 2.50–3.25% above SOFR. Conventional investment property ARMs may have tighter margins, but DSCR programs price in additional risk. The fully-indexed rate (SOFR + margin) is what your payment is based on at each adjustment, subject to caps.
Should I refinance before my ARM adjusts?
It depends on the rate environment at adjustment time and your break-even on a refi. If the fully-indexed rate at adjustment would be similar to or below available fixed rates, there's no urgency. If it would be materially higher and you have equity, refinancing to a fixed rate before adjustment can be worthwhile. Run the refi break-even calculator with the projected post-adjustment payment as your 'current P&I' input.