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LPT Loan Projection Tool Mortgage projection calculators

ARM reset basics

ARM Caps Explained

ARM caps are limits written into an adjustable-rate mortgage. They control how far the interest rate can move at a reset and over the life of the loan. Floors work in the opposite direction: they stop the rate from dropping below a minimum level.

Model ARM Caps View Methodology
Budgeting estimate only. This tool is not legal, tax, or financial advice. Outputs are rough projections based on user-entered assumptions and should not be treated as a lender payoff quote or guaranteed result.
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Initial adjustment cap

The initial adjustment cap limits how much the rate can change at the first reset after the introductory fixed period ends.

First reset Payment shock control

Periodic adjustment cap

A periodic cap limits how much the rate can move from one later adjustment to the next. For example, a 1% periodic cap means the rate cannot rise or fall by more than one percentage point at that reset.

Each reset Ongoing limit

Lifetime ceiling

The lifetime ceiling is the maximum rate the ARM can reach during the loan term. Even if the index and margin would produce a higher rate, the loan should not exceed its contractual ceiling.

Maximum rate Worst-case input

Rate floor

The floor is the minimum rate the ARM can reach. It matters in lower-rate scenarios because the borrower may not receive the full benefit of falling market rates below the floor.

Minimum rate Best-case input

How to read cap shorthand

ARM caps are often shown as a sequence such as 2/1/5 or 5/2/5. The exact meaning depends on the loan documents, but the common reading is: first reset cap / later reset cap / lifetime cap above the starting rate.

2 / 1 / 5 = first adjustment may rise up to 2%, later adjustments up to 1%, lifetime increase up to 5%
Use your note, rider, or lender disclosure as the source of truth. The calculator’s ceiling, floor, and increment fields are scenario-planning inputs, not a substitute for your actual loan terms.

How this tool uses caps and floors

The ARM Projection Tool uses the rate ceiling, rate floor, and rate increment to build simplified best, neutral, and worst case paths.

  • Worst case increases by the increment until the ceiling is reached.
  • Best case decreases by the increment until the floor is reached.
  • Neutral keeps the initial rate flat, while still allowing scheduled recasts when enabled.

What caps do not do

Caps do not guarantee affordability, payoff timing, or future market rates. They only limit how the loan’s rate can move under its reset rules.

  • Taxes, insurance, escrow, and fees can still change total housing cost.
  • A recast can change scheduled P&I even when the rate movement is capped.
  • Servicer calculations may differ from a simplified budgeting model.

Simple example

Suppose an ARM starts at 5.25%, has a 10.25% ceiling, a 4.25% floor, and adjusts in 1.00% increments in the calculator. The projected worst case would step upward until it reaches 10.25%. The projected best case would step downward until it reaches 4.25%.

Planning use: caps and floors are most useful for estimating reset exposure. They help frame the range of possible payments, but they do not predict where rates will actually be.