Mortgage recast calculator
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New monthly principal + interest
—Enter your loan to compare.
Principal + interest only. No escrow, taxes or insurance. This is not financial advice.
Three paths, one starting point
Your balance over time
Solid green: recast. Dashed ink: baseline. Dotted ink: same lump sum, no recast. Schedule below is the text alternative.
Amortization schedule
This is not financial advice.
Saved scenarios
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This is not financial advice.
A mortgage recast spreads your remaining loan balance over the time left on your loan after a lump-sum principal payment. Your interest rate stays the same. Your required principal-and-interest payment can fall, but the lump sum still leaves your savings.
Use this calculator to compare a recast with making the same principal payment without a recast. Enter your own loan; the comparison appears only after you calculate.
Short steps
- Enter your current unpaid principal balance, note rate, remaining months and proposed lump sum.
- Optionally add a recast fee you were quoted, or leave it blank.
- Calculate to compare three paths for your inputs: continue as scheduled, lump sum plus recast, and the same lump sum without recasting.
- Read the schedule and guides for column meanings and eligibility questions.
What the three paths show
- Continue as scheduled — baseline remaining interest with no lump sum.
- Pay a lump sum and recast — lower recalculated payment over the same remaining term.
- Pay the same lump sum without recasting — keep the existing payment for an earlier payoff.
If you recast but voluntarily keep paying the old amount, the modeled payoff matches the extra-principal path when the balance, rate, payment dates and principal allocation are identical, before any separate fees.
Guides
- What is a mortgage recast?
- Extra principal payments
- Amortization schedule
- Recast vs refinance
- Recast fees
- FAQ
The payment basis follows Fannie Mae's re-amortization guidance.
Method and transparency
Last updated: 6 November 2026. Local technical preview only. This is not financial advice.