Result
Save $97,967.24 and finish 5 years 2 months sooner
Applying $20,000.00 to principal now shortens estimated payoff from 30 years to 24 years 10 months while keeping the scheduled payment unchanged.
- Scheduled payoff time
- 30 years
- New payoff time
- 24 years 10 months
- Interest saved
- $97,967.24
- Interest after lump sum
- $284,661.80
- Balance after lump sum
- $280,000.00
- Scheduled principal and interest payment
- $1,896.21
Estimate only. Not financial advice, loan approval, or a quote. Confirm rates, taxes, insurance, lender terms, and fees before making decisions. Read the full disclaimer.
More
At a glance
- Cost
- Free
- Login
- Not required
- Best use
- Compare a mortgage's scheduled payoff with applying a one-time lump-sum payment directly to principal while keeping the regular payment unchanged.
- Output
- Browser result with print and PDF options
Result summary
Quick answer
With the sample inputs, this calculator returns Save $97,967.24 and finish 5 years 2 months sooner. Scheduled payoff time: 30 years. Use Save $97,967.24 and finish 5 years 2 months sooner as a planning estimate, then verify rates, fees, taxes, insurance, and terms with current lender or account data before making a commitment.
Instructions
How to use this calculator
Open the short walkthrough for choosing and checking inputs.
The calculator applies the lump sum to principal immediately, then models the remaining balance with the same scheduled principal-and-interest payment. It compares that payoff schedule with making no lump-sum payment.
Page guide
On this page
Jump directly to the part of the calculator you need.
Calculation details
Formula and methodology
See the exact math used to produce the result.
Lump-sum comparison = the scheduled fixed-rate payoff path versus applying the lump sum to principal now and keeping the scheduled payment unchanged.
Before acting
Assumptions to check
Review the real-world details that can change the estimate.
The key inputs are Remaining mortgage balance, Interest rate, Scheduled principal and interest payment, Lump sum applied to principal. Confirm APR, payment timing, lender fees, taxes, insurance, payoff terms, and local costs before making financial decisions.
More guidance Examples, methodology, and planning checks Open the worked example, review notes, reference tables, and practical next checks.
When to round up
Use only the principal-and-interest portion of the payment. Confirm prepayment rules and principal-only posting with the servicer. This is not a mortgage recast: the scheduled payment stays unchanged, and escrow, fees, daily-interest timing, and recast charges are not modeled.
When to use this calculator
- Comparing payments before committing
- Testing one financial input at a time
- Preparing questions for a lender, dealer, or budget review
Tips for better estimates
- Use the actual APR and loan term when available.
- Add taxes, insurance, fees, PMI, HOA, or maintenance when they apply.
- Treat the result as a planning estimate, not approval or a quote.
How this estimate was built
This page applies the entered lump sum to principal immediately, then accrues monthly interest and keeps the scheduled principal-and-interest payment unchanged. It is a prepayment comparison, not a mortgage recast or a new lender payment schedule.
Worked example
Example inputs: Remaining mortgage balance: $300000; Interest rate: 6.5 %; Scheduled principal and interest payment: $1896.21 /month; Lump sum applied to principal: $20000. With those values, the calculator returns Save $97,967.24 and finish 5 years 2 months sooner. Applying $20,000.00 to principal now shortens estimated payoff from 30 years to 24 years 10 months while keeping the scheduled payment unchanged.
Example scenarios
- Applying $20,000 immediately to a $300,000 mortgage balance at 6.5%, while keeping a $1,896.21 principal-and-interest payment, shortens the estimate from 30 years to 24 years 10 months.
- In that example, estimated remaining interest falls by about $97,967.24 because future monthly interest starts from a $280,000 balance.
- This models a principal prepayment, not a recast: the scheduled payment stays $1,896.21 rather than being recalculated by the lender.
- Confirm principal-only posting, prepayment penalties, daily-interest timing, and any recast requirements with the mortgage servicer before sending money.
Quick reference chart
| Sample result | Save $97,967.24 and finish 5 years 2 months sooner |
|---|---|
| Scheduled payoff time | 30 years |
| New payoff time | 24 years 10 months |
| Interest saved | $97,967.24 |
| Interest after lump sum | $284,661.80 |
| Best next step | Use this as a planning estimate, then compare it with real lender terms, APR, fees, taxes, insurance, and local costs before committing. |
FAQs
Mortgage Lump-Sum Payment Calculator questions
Can I use this result as a final quote?
No. Use it as a planning estimate, then compare with lender quotes, APR, taxes, insurance, fees, and local costs.
Should I add a safety margin?
Yes. Leave room for PMI, insurance changes, taxes, maintenance, fees, and rate differences. A calculator result should not be treated as a lender quote.
What should I check before deciding?
Check the actual APR, payment schedule, taxes, insurance, closing costs, lender fees, and whether the payment fits your full budget.
Can this replace professional financial advice?
No. It is a planning estimate, not financial advice, underwriting, approval, or a loan offer.
Is the mortgage lump-sum payment calculator exact?
No. It is a planning estimate, not a quote, approval, or financial advice. Compare the result with real APR, lender terms, taxes, insurance, and fees.
What inputs matter most?
Remaining balance, rate, scheduled principal-and-interest payment, and the immediate lump-sum amount determine the comparison.
More resources Saved tools and additional links Open optional follow-ups, common mistakes, and more calculators.
Saved tools
Saved calculators
- No saved calculators yet.
Recent tools
Recent calculators
- Recent calculators will appear here.
Common planning mistakes
Confusing a principal prepayment with a recast, assuming the required payment will fall, entering an escrow-inclusive payment, and sending a lump sum without confirming principal-only posting or prepayment terms.
Was this calculator helpful?
Suggest an improvementNotice an issue with this calculator? Contact us here.