Fixed interest rate
Used directly in this page's monthly amortization formula.
Free payment plannerModel 2026.08 · Reviewed 2026-08-22
Whole House Generator Financing Calculator
Estimate a fixed monthly payment, total interest, total of payments, and total project cash outlay before comparing written generator financing offers.
No lender matching, rate claim, credit check, approval estimate, or application. Your values stay in this browser session.
- Fixed-rate model
- Rate sensitivity
- No signup
01 Fixed-rate payment planner
Estimate monthly payment and total borrowing cost.
Enter a cash project price, down payment, financed fees, fixed annual interest rate, and term. The result updates only after a valid field is committed.
Change first: project cost and the rate from a written offer.
02 Same project, different term
A lower monthly payment can carry more total interest.
These three rows hold the default $13,720 project and 10.00% fixed annual rate constant. Only the term changes.
| Term | Monthly | Interest | Total payments |
|---|---|---|---|
| 36 months | $442.71 | $2,217 | $15,937 |
| 60 months | $291.51 | $3,771 | $17,491 |
| 84 months | $227.77 | $5,413 | $19,133 |
Planning output, not a rate offer. Real payment schedules can differ because of fee treatment, payment dates, daily interest, odd periods, and creditor rounding.
Fixed-rate level payment
P × r × (1+r)n÷(1+r)n − 1
- P
- Modeled amount financed
- r
- Annual interest rate ÷ 12
- n
- Number of monthly payments
03 Transparent method
The calculator models one regular fixed-rate schedule.
Project balance equals project cash price minus down payment. Entered fees are then added to principal. The monthly payment is calculated at full precision, and displayed payments and totals are rounded only at the end.
The model assumes a single advance, equal monthly periods, equal payments, no balloon, and no irregular first or final period. Those boundaries keep the number explainable and reproducible.
04 Rate and fee boundary
Interest rate, APR, and financed fees are not interchangeable.
CFPB guidance describes the interest rate as the charge for borrowing and APR as a broader yearly measure that can include lender fees. A creditor's written disclosure controls the real classification.
APR
May combine the interest rate with additional lender fees.
Financed fees
Added to modeled principal only when the written offer does so.
Disclosures
Use the written amount financed, finance charge, APR, and schedule.
Resolve before signing“0% APR”is not the same wording as“No interest if paid in full”
05 Promotional financing
Deferred interest needs its own payoff check.
CFPB guidance explains that deferred interest can be charged back to the purchase date if the promotional balance remains unpaid by the deadline or offer conditions are broken. A minimum monthly payment may also be too small to clear the balance in time.
This calculator deliberately excludes deferred-interest logic. Record the payoff deadline, balance that must reach zero, interest rate used if the condition fails, late-payment rules, and payment allocation before comparing it with a fixed-rate installment loan.
06 Written-offer checklist
Compare the contract fields, not the headline payment.
Ask for one written project scope and one written credit disclosure for every offer. Keep contractor pricing questions separate from lender terms so a lower payment does not hide a different project.
- 1What is the cash project price?
Separate equipment and installation scope from the cost of borrowing.
- 2What amount is financed?
Reconcile the cash price, down payment, financed fees, and any prepaid finance charge.
- 3What are the interest rate and APR?
Compare rate to rate and APR to APR; record why they differ.
- 4How many payments, and how much is each?
Check the first, regular, and final payment plus every due-date convention.
- 5What is the total of payments?
Use the full scheduled sum to compare a lower payment with a longer term.
- 6What changes after a missed or early payment?
Check late charges, deferred-interest conditions, prepayment terms, and allocation rules.
07 Sources and assumptions
Federal disclosure guidance, generator-market evidence, and visible internal assumptions.
CFPB sources own the disclosure and promotional-financing boundaries. Generator Budget owns the narrow payment model, validation limits, ±2-point sensitivity, and rounding.
Consumer Financial Protection Bureau
Appendix J to Part 1026 — Annual Percentage Rate Computations for Closed-End Credit Transactions
Actuarial-method context for single-advance closed-end credit, regular payment periods, and equal-payment schedules.
The page is a planning calculator, not a creditor disclosure engine. It applies a narrower fixed-rate monthly-payment formula and does not claim Regulation Z compliance for a real transaction.Open sourceConsumer Financial Protection Bureau
12 CFR § 1026.18 — Content of disclosures
Definitions and disclosure context for amount financed, finance charge, annual percentage rate, payment schedule, total of payments, and prepayment terms.
The calculator labels its own output as modeled interest and borrowing cost because classifying a real fee as a finance charge depends on the actual transaction and creditor disclosure.Open sourceConsumer Financial Protection Bureau
What is the difference between a loan interest rate and the APR?
The distinction between a contract interest rate and an APR that can incorporate additional lender fees.
The calculator asks for the fixed annual interest rate used for payment modeling. Entering an APR instead creates only a comparison proxy when that APR includes fees.Open sourceConsumer Financial Protection Bureau
I got a credit card promising no interest for a purchase if I pay in full within 12 months. How does this work?
Deferred-interest risk: unpaid promotional balances can trigger interest traced back to the original purchase date under the offer terms.
Deferred-interest schedules remain outside the fixed-rate model and receive a visible resolve-before-signing warning.Open sourceGenerac
Home Generator Financing Options
Current generator-market evidence that fixed-payment terms, activation fees, and deferred-interest promotions appear in manufacturer-linked financing offers.
Offer terms can change. No Generac rate, term, fee, lender, approval statement, or payment factor is used as the calculator default or recommendation.Open sourceOpen the field-to-evidence ledger
| Assumption group | Model fields | Basis | Boundary |
|---|---|---|---|
| Project balance and entered financed fees | projectCost, downPayment, financedFees, amountFinanced | External reference + internal planning assumption | A real creditor may classify or disclose a fee differently. The calculator does not determine a legal amount-financed or finance-charge disclosure. |
| Fixed-rate level monthly payment | calculateLevelMonthlyPayment, calculateScenario | External reference + internal planning assumption | One fixed-rate, fully amortizing, single-advance loan with equal monthly payments and no irregular first or final period. |
| Low / entered / high rate comparison | FINANCING_RATE_SENSITIVITY_PERCENTAGE_POINTS, low, typical, high | Internal planning assumption | This visible sensitivity range is not a rate forecast, market range, lender offer, or approval estimate. Replace it with actual written offers. |
| Display rounding | roundCurrency, roundRate | Internal planning assumption | A real payment schedule can differ because of payment-date conventions, odd periods, daily interest, fee treatment, or creditor rounding. |
| APR, fee, and deferred-interest boundary | FINANCING_BOUNDARY | External reference | Visitors must use the creditor's written disclosures for APR, fees, promotional conditions, prepayment, late payment, and final payment terms. |
08 FAQ
Generator financing questions, answered with the model boundary visible.
How much is a whole house generator per month with financing?
For this page's editable $13,720 project example, no down payment or financed fees, a 10.00% fixed annual interest rate, and a 60-month term, the modeled payment is $291.51 per month. The sensitivity cases are $278.19–$305.19 at the entered rate minus or plus 2 percentage points. Replace every starting input with a written project price and credit offer.
Can generator installation be included in financing?
Some generator financing offers can cover equipment and installation, but eligible scope depends on the lender, dealer, contractor, and written agreement. Enter only the cash project scope and fees shown in the documents you are comparing. The calculator does not decide eligibility or approval.
What interest rate should I use for a generator loan estimate?
Use the fixed contract interest rate from a written offer when available. The default 10.00% is a round, editable planning input rather than a lender-derived quote. If the document shows only APR, the payment result is a comparison proxy because APR can include lender fees that the contract interest rate does not.
Is APR the same as the interest rate?
No. CFPB guidance distinguishes the interest rate charged for borrowing from APR, which can incorporate the interest rate plus additional lender fees. This calculator uses the annual interest-rate input in a level-payment formula and lists entered financed fees separately; it does not calculate a lender-disclosed APR.
Is no interest if paid in full the same as 0% APR?
Not necessarily. CFPB guidance explains that a deferred-interest offer can add interest traced back to the purchase date if the promotional balance is not fully paid by the deadline or other conditions are broken. The fixed-rate calculator does not model deferred interest, so review the exact promotional wording and payoff requirement separately.
Does a longer generator financing term save money?
A longer term usually lowers the monthly payment in this fixed-rate model but increases total interest when the annual rate and amount financed stay the same. Compare both monthly payment and total of payments rather than choosing from the monthly figure alone.
Which financing fees should I enter?
Enter only fees the written offer adds to the loan principal. Keep fees paid in cash outside the financed-fee input. A real lender's amount-financed, finance-charge, and APR disclosures control because fee classification depends on the transaction.