Finance category
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Rate Lock Float Down Calculator
A float-down lock lets you re-price to a lower rate if market rates drop during your lock period. Costs 0.125-0.375% extra upfront. This calculator evaluates whether it's worth the premium.
Net expected value of float-down
$6,141
Prob-weighted savings
$7,141
Float-down fee
$1,000
Savings if drop occurs
$23,803
How the math works
$400K, 0.25% fee = $1,000. 30% prob × 0.25% drop = $75K lifetime savings × 30% = $22,500 expected. Net value $21,500. Big positive.
Most accurate when rates are high and Fed is signaling cuts. Skip if rates are at recent lows or stable. Negotiable — ask lender for free float-down if rates drop.
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 Rate Lock Float Down Calculator is built to give a quick, browser-based estimate for rate lock float down. A float-down lock lets you re-price to a lower rate if market rates drop during your lock period. Costs 0.125-0.375% extra upfront. This calculator evaluates whether it's worth the premium. 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 rate lock float down 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 rate lock float down 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 standard lock rate, float-down rate, and float-down fee.
- Estimate probability and expected size of rate drop.
- See expected value of the float-down option.
Frequently Asked Questions
When is float-down worth it?
In volatile rate environments or long lock periods (60+ days). If you're locking when rates are near recent highs and Fed signals cuts, float-down can be valuable.
How much drop to recover fee?
A 0.125% float-down fee on $400K = $500. To recover with lifetime payment savings, need rate to drop 0.125% and qualify for drop. 10-25% of floats are exercised.
Float-down vs extension?
Different purposes. Float-down: rates go DOWN and you benefit. Extension: rates go UP but you keep old lock. Both protect against rate changes; float is proactive/optional, extension is reactive/mandatory.
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