Auto Loan Balloon Payment Calculator with Bi-Weekly Payments
This calculator estimates periodic payments and balloon amounts for auto loans that include a lump sum due at the end of the term. It supports bi‑weekly, semi‑monthly and monthly payment schedules and two directions of calculation: compute the periodic payment when a balloon is specified, or compute the balloon amount when a periodic payment is specified.
Results are estimates intended for planning and comparison. Actual amounts may differ due to lender rounding rules, payment timing conventions, fees, insurance escrows, and local taxes. Use this tool to compare scenarios and verify figures with the lender before signing any loan documents.
Calculates the periodic payment amount when the loan includes a balloon due at the end of the term. Handles zero interest rate as a special case.
Inputs
Results
Periodic payment
$418.41
Total number of payments
60
Balloon due at maturity
$5,000.00
Estimated total interest
$5,104.38
| Output | Value | Unit |
|---|---|---|
| Periodic payment | $418.41 | currency |
| Total number of payments | 60 | payments |
| Balloon due at maturity | $5,000.00 | currency |
| Estimated total interest | $5,104.38 | currency |
Visualization
Methodology
We convert APR to a periodic rate using the selected frequency: periodic_rate = APR / 100 / payments_per_year, where payments_per_year is 26 for bi‑weekly, 24 for semi‑monthly, or 12 for monthly.
The loan present value equals principal plus any financed fees. For a loan with a balloon, the present value of the balloon is discounted to the same periodic basis. The periodic payment is solved from the standard annuity formula with the balloon present value subtracted from the financed amount.
Special handling: when the periodic interest rate is zero, the calculator uses linear division of principal (minus balloon present value) across payments to avoid division by zero.
Key takeaways
Use the default 'Compute periodic payment' method to find what bi‑weekly or monthly payment will be when a balloon is due at maturity.
Use the 'Compute balloon amount' method when you know the regular payment and want to find the required balloon that makes the loan balance reconcile.
Always confirm lender disclosures for exact payoff amounts, rounding, and additional fees.
Further resources
Expert Q&A
Does this calculator reflect exact lender payoff schedules and late‑payment rules?
No. This tool produces standard mathematical estimates. Lenders may apply daily interest accrual, different compounding conventions, rounding to cents, or additional finance charges. Use results for planning and confirm the final payoff and disclosure with the lender.
Why is bi‑weekly different from semi‑monthly?
Bi‑weekly uses 26 equal payments per year (every two weeks). Semi‑monthly uses 24 payments (twice a month). These produce different periodic rates and schedules even when annual APR is identical.
What accuracy and computational standards were considered?
Calculations follow standard financial formulas for annuities and discounted lump sums. For numerical reliability and floating point behavior we reference established computing standards such as IEEE 754 for floating point representation, and guidance from NIST on numerical accuracy. Results are rounded to currency precision for display but underlying math may use double precision. For legal disclosures and regulatory compliance consult applicable financial regulations and your lender.
Can I use this for lease balloon or commercial loans?
The formulas model a loan with periodic fixed payments plus a lump-sum balloon at maturity. They do not include tax, insurance escrows, conditional residual values on leases, or specialized commercial adjustments. Adapt inputs to match your contract and verify with the issuer.
Sources & citations
- National Institute of Standards and Technology (NIST) — https://www.nist.gov
- International Organization for Standardization (ISO) — https://www.iso.org
- IEEE - Floating point standard (general reference) — https://www.ieee.org
- Occupational Safety and Health Administration (OSHA) - general standards — https://www.osha.gov