$300,000 balance, 6%, 25 years left
Lump-sum principal: $50,000
Old payment: about $1,933
Recast payment: about $1,611
Rate and maturity remain unchanged
A servicing fee and eligibility rules may apply
Read the sequence from the starting balance through the trigger or exit date.
Follow the decision over time
Recast and prepayment differ
Both reduce principal. A recast changes the required payment; ordinary prepayment generally keeps the payment and ends the loan earlier.
Refinancing replaces the loan
A refinance can change rate and term but adds closing costs and new approval risk. Recast economics are usually simpler.
This decision belongs in The Real Cost of a Mortgage. Use Mortgage Refinance Break-Even: Payment Savings Are Only the First Test to check the next assumption, then test the numbers in the Refinance Break-Even Calculator.
Cash becomes illiquid equity
The lump sum is difficult to retrieve without sale or borrowing. Preserve adequate reserves before optimizing payment.
Not every mortgage qualifies
Investor, government-program, seasoning and minimum-payment rules vary by servicer and contract.
Build the decision timeline
A recast applies a principal reduction and recalculates payment without replacing the loan. Compare its fee and liquidity cost with ordinary prepayment and refinancing, which change different parts of the contract.
Lender details needed for the choice
- Minimum lump sum, recast fee and eligibility rules.
- New payment estimate with rate and maturity unchanged.
- Refinance quote and ordinary principal-prepayment alternative.
- Ask the servicer for written eligibility and fee terms.
- Calculate balance after the lump sum.
- Compare recast, principal-only and refinance paths.
- Measure both payment relief and lifetime interest.
- Retain emergency liquidity before sending funds.
Timing risks that change the cost
- Calling the entire lump sum a recast fee.
- Assuming the interest rate changes.
- Comparing recast payment with a restarted thirty-year refinance only.
- Using all available cash and ignoring liquidity.
Test the dates and balances
Refinance Break-Even Calculator
Find when closing costs are recovered - And whether the new term quietly increases lifetime cost.
Questions this decision usually raises
Does recasting save more interest than prepaying?
No. The principal reduction saves interest; keeping the old higher payment after prepayment normally saves more than lowering it.
Will maturity change?
A standard recast generally preserves maturity, but verify the servicer's terms.
Does a recast remove mortgage insurance?
Not automatically. Mortgage-insurance cancellation follows separate balance, payment-history, property-value and servicer rules that should be confirmed in writing.
Verify the dates, triggers and limits
This page explains a calculation, not a personal recommendation. Contract rules and consumer protections vary by product and jurisdiction. Check the current agreement and official guidance before acting.