Mortgage Recast Calculator
Lump to principal, then rebuild the payment at the same rate and remaining term. Click any i for detail.
Loan
Current balance ($)
i
Balance
Principal remaining before the recast. |
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|---|---|
Interest rate (%)
i
Rate
Note rate. Recasts usually keep the rate. |
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Months remaining
i
Term left
Schedule left, not the original term. |
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Lump principal ($)
i
Lump
Amount applied to principal at recast. Servicers often have a minimum and a fee. |
How to use this calculator
- Enter remaining principal.
- Enter note rate and months left.
- Enter the lump.
- Compare old vs new P&I.
Results explained
New balance = current − lump. New P&I uses the standard amortizing formula over the same remaining months. Extra monthly principal without a recast keeps the payment the same and shortens the term instead — that’s the extra-payment payoff page.
Quick reference: recast vs extra payments
Recast lowers the payment. Extra principal keeps the payment, ends earlier.
| Item | Detail |
|---|---|
| Same rate/term | Typical recast |
| Refi | New rate/term/fees |
| Fee | Often a few hundred dollars — not in this math |
| Escrow | Still on top of P&I |
Ask the servicer whether your product even allows recasts.
How the estimate is built
newPmt = pmt(balance − lump, rate, months remaining).
Example scenario
$320k left, 6.25%, 300 months, $40k lump → payment drops by the amount shown on the result.
FAQ
Is this a refi?
No. Rate usually stays put.
Taxes and insurance?
Not in P&I.
Partial extra each month?
Use mortgage payoff with extra payments.