№ 005 · Mortgage cluster
Mortgage Recast Calculator
A recast is the quiet third option for your mortgage: drop a lump sum on the principal and the lender re-amortizes the smaller balance over the same remaining term. Your rate and payoff date stay put — only the payment gets smaller. This calculator shows exactly how much smaller.
New payment · monthly reduction · interest saved
Want to lower your rate instead? See the Refinance Calculator. Want to pay the loan off faster? See the Loan Payoff Calculator. Borrowing against your equity instead? The HELOC Calculator.
Your current loan01
$
%
The lump sum02
$
$
New monthly payment
$1,675.18
$257.72/mo lowerSame payoff date · 25 years left
Before recast
Monthly P&I$1,932.90
$279,871.26 interest left
over 300 more payments
over 300 more payments
After recastLower
Monthly P&I$1,675.18
$242,555.09 interest left
over the same 300 payments
over the same 300 payments
Monthly reduction$257.72
Interest saved$37,316.17
Out of pocket$40,250.00
- Before recast
- After recast
| Start | Before recast $300,000.00, After recast $260,000.00 |
|---|---|
| Year 2.5 | Before recast $286,025.85, After recast $247,889.07 |
| Year 5.0 | Before recast $269,796.26, After recast $233,823.43 |
| Year 7.5 | Before recast $250,947.22, After recast $217,487.59 |
| Year 10.1 | Before recast $228,268.32, After recast $197,832.54 |
| Year 12.6 | Before recast $202,716.66, After recast $175,687.77 |
| Year 15.1 | Before recast $173,040.97, After recast $149,968.84 |
| Year 17.6 | Before recast $138,575.62, After recast $120,098.87 |
| Year 20.2 | Before recast $97,107.39, After recast $84,159.73 |
| Year 22.7 | Before recast $50,386.35, After recast $43,668.17 |
| Year 25.0 | Before recast $0.00, After recast $0.00 |
Remaining balance · by year
| Year | Current balance | After recast | Lower by |
|---|---|---|---|
| 1 | $294,659.88 | $255,371.90 | $39,287.98 |
| 2 | $288,990.40 | $250,458.35 | $38,532.05 |
| 3 | $282,971.23 | $245,241.74 | $37,729.49 |
| 4 | $276,580.82 | $239,703.38 | $36,877.44 |
| 5 | $269,796.26 | $233,823.43 | $35,972.83 |
| 6 | $262,593.24 | $227,580.81 | $35,012.43 |
| 7 | $254,945.96 | $220,953.16 | $33,992.80 |
| 8 | $246,827.01 | $213,916.74 | $32,910.27 |
| 9 | $238,207.30 | $206,446.32 | $31,760.98 |
| 10 | $229,055.94 | $198,515.15 | $30,540.79 |
| 11 | $219,340.15 | $190,094.80 | $29,245.35 |
| 12 | $209,025.11 | $181,155.10 | $27,870.01 |
| 13 | $198,073.86 | $171,664.01 | $26,409.85 |
| 14 | $186,447.16 | $161,587.54 | $24,859.62 |
| 15 | $174,103.36 | $150,889.58 | $23,213.78 |
| 16 | $160,998.21 | $139,531.78 | $21,466.43 |
| 17 | $147,084.77 | $127,473.46 | $19,611.31 |
| 18 | $132,313.17 | $114,671.42 | $17,641.75 |
| 19 | $116,630.50 | $101,079.77 | $15,550.73 |
| 20 | $99,980.55 | $86,649.81 | $13,330.74 |
| 21 | $82,303.68 | $71,329.85 | $10,973.83 |
| 22 | $63,536.53 | $55,064.99 | $8,471.54 |
| 23 | $43,611.86 | $37,796.94 | $5,814.92 |
| 24 | $22,458.28 | $19,463.84 | $2,994.44 |
| 25 | $0.00 | $0.00 | $0.00 |
How it works · methodology
The math, in the open.
payment P&I = L · [ r(1+r)^n ] / [ (1+r)^n − 1 ] new balance = current balance − lump sum new payment = P&I on the new balance over the SAME n months monthly reduction = current payment − new payment interest saved = current remaining interest − new remaining interest
- L
- Loan balance (before, then after the lump sum)
- r
- Monthly interest rate (APR ÷ 12), unchanged
- n
- Months remaining, unchanged by the recast
- lump sum
- One-time principal payment, paid out of pocket
Assumptions & limits
- The rate and the number of months remaining do not change — that is the definition of a recast, and what separates it from a refinance.
- The lump sum is applied entirely to principal; the recast fee, if any, is a separate out-of-pocket cost and is not added to the balance.
- Both loans are fixed-rate and fully amortizing; the current payment is the scheduled P&I on the remaining balance.
- Interest saved is the lump sum’s payoff over the life of the loan; it does not account for what that money could have earned invested elsewhere. An estimate, not a loan offer.
By the MintNumber Editorial Team·Reviewed
Frequently asked
Questions about recasting
What is a mortgage recast?
A recast — also called re-amortization — keeps your existing loan, interest rate, and remaining term exactly as they are. You make a one-time lump-sum payment toward the principal, and the servicer recalculates your monthly payment on the smaller balance over the same number of months left. The result is a lower payment with the same payoff date, and no new loan to apply for.
How is a recast different from refinancing?
Refinancing replaces your loan with a brand-new one — a new rate, a new term, and several thousand dollars in closing costs. A recast changes none of those: same rate, same payoff date, just a smaller balance and payment after your lump sum. Recasting is usually a flat fee of $150–500 rather than full closing costs, but it cannot lower your rate. If rates have dropped since you borrowed, compare against the refinance calculator; if they have risen, a recast keeps your good rate while still cutting the payment.
How is a recast different from just paying extra each month?
Both put more money toward principal, but they pull different levers. Extra monthly payments — what the loan payoff calculator models — keep your payment the same and shorten the term, so you finish years early. A recast keeps the term the same and lowers the payment. Pay extra to get out of debt sooner; recast to free up monthly cash flow. A recast does not get you out of debt any faster than the original schedule.
Does recasting save me interest?
Yes — putting a lump sum on principal means interest accrues on a smaller balance for the rest of the loan, so you pay less total interest. The interest-saved figure here is exactly that reduction. Keep in mind the lump sum comes out of your pocket today, so weigh it against what that money could earn invested elsewhere; this tool shows the interest the recast saves, not that opportunity cost.
Can every loan be recast?
No. Most conventional loans (Fannie Mae / Freddie Mac) allow a recast, usually with a minimum lump sum and a flat fee, but government-backed loans — FHA, VA, and USDA — generally do not. Rules, minimums, and fees vary by servicer, so confirm with yours before counting on a recast. Enter the fee your servicer quotes above; the calculator treats it as an out-of-pocket cost on top of the lump sum.