About this Mortgage Recast Calculator
A mortgage recast lowers the payment by recalculating the remaining balance over the remaining term after a lump-sum principal payment.
Who this calculator is for
- Homeowners comparing real-life household costs.
- Renters and buyers building a practical monthly budget.
- Families testing assumptions before a repair, upgrade, or purchase.
When to use it
- Estimate the budget impact before making a home decision.
- Compare quotes with consistent assumptions.
- Turn usage, rates, and maintenance assumptions into transparent outputs.
How to use this calculator
- Enter your household usage, project, or payment assumptions.
- Replace defaults with local rates, quote values, and utility prices.
- Review the primary output and compare scenarios by changing one input at a time.
Key assumptions
- All prices, rates, taxes, and usage values are entered by the user.
- Calculations run locally in your browser and are not stored by Calwarden.
- This is planning math, not financial, tax, engineering, or legal advice.
Accuracy and testing
Review formula sources, default test cases, assumptions, unit handling, rounding rules, and changelog for this calculator.
How this calculator works
Current payment is based on current balance and remaining term. Recast payment uses balance minus lump-sum payment over the same remaining term.
Monthly payment uses the standard amortization formula before and after subtracting the lump-sum principal payment.
Inputs explained
Rates and prices
Use your current utility bill, HOA statement, tax notice, quote, or lender estimate where possible.
Usage assumptions
Enter expected daily, monthly, or annual usage rather than relying on national averages.
Planning period
Use a realistic ownership or analysis period for ROI and comparison calculators.
Understanding your results
Results are planning estimates. Local tariffs, taxes, weather, building condition, loan terms, and contractor quotes can materially change the real outcome.
Example scenarios
Practical scenario
A $350,000 balance with a $50,000 recast payment at 6.25% over 25 years lowers the payment based on a $300,000 recast balance.
Key Features
- Instant Calculation
- Private & Secure
- Mobile Optimized
Tips & Best Practices
- Use all-in rates when bills separate supply, delivery, taxes, and fees.
- Run conservative and optimistic cases before making a purchase decision.
- Keep quote-specific rebates, maintenance, and financing terms separate when they matter.