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Assumption Vs Refi Decision Calculator
Assumption captures below-market debt.
Assumption advantage
$2,325,000
Interest savings
$2,250,000
Assumption vs refi fee diff
$75,000
How the math works
Rate diff = new − existing. Interest savings = balance × diff × years. Fee diff = refi − assumption.
$15M × 3% × 5 = $2.25M interest savings. + $75k fee diff = $2.33M advantage. Strong case for assumption.
EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.
Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.
Learn more about our review process on the EveryCalc methodology page.
How this calculator works
What this page estimates
This Assumption Vs Refi Decision Calculator is built to give a quick, browser-based estimate for assumption vs refi decision. Assumption captures below-market debt. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.
Calculation approach
The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.
Example workflow
For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.
Practical checks
- Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
- Run a low, base, and high case when the inputs are estimates.
- Check the related calculators below when the next decision depends on a different assumption.
How to interpret the assumption vs refi decision result
Best use
Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.
Cross-check
Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.
Watch for
Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.
This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.
Before relying on this assumption vs refi decision estimate
Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.
Confirm source numbers
Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.
Separate cash flow from total cost
A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.
Run conservative cases
Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.
Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.
How to Use
- Enter loan balance.
- Enter existing rate %.
- Enter new loan rate %.
- Enter years remaining.
- Enter assumption fee %.
- Enter refi costs %.
- Read assumption advantage.
Frequently Asked Questions
Assumption mechanics?
New buyer takes over existing loan. Lender reviews and approves buyer. Buyer pays: assumption fee (0.5-1.5% of balance), legal costs, existing loan terms continue. Alternative: pay off existing, refinance with new loan at current rates.
When favorable?
Existing rate far below current market. Low rate locks for remaining years save substantial interest. 2024-25 market: assumption of 3-4% loans vs new at 6-7% can save $100k-1M+ over remaining term.
Obstacles?
Lender approval required. Good-quality buyer credit. Buyer often wants more loan than assumable balance — requires mezzanine or equity. Complex on CMBS (defeasance vs assumption). Time-intensive due diligence (30-90 days).
How often should I rerun this?
Rerun this calculator whenever inputs change materially — new rent roll data, rate moves, loan balance updates, or quarterly operating data. For active deals, monthly refresh is typical. For stabilized assets under monitoring, quarterly is fine. Treat the output as a decision tool, not a one-time answer — market conditions evolve and so should your analysis.
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