Example Data Table
| Date | Amount | Type | Meaning |
|---|---|---|---|
| 2026-01-20 | 1200 | payment | Partial regular payment received early. |
| 2026-02-10 | 500 | extra_payment | Extra amount applied using selected priority. |
| 2026-03-05 | 35 | fee | Added servicing or late fee. |
| 2026-04-01 | 8.75 | rate_change | New annual rate begins on this date. |
| 2026-05-18 | 2000 | payment | Large irregular payment near review date. |
Formula Used
The calculator accrues interest between dated events.
Interest = Interest Base × Annual Rate × Days ÷ Day Basis
The interest base is the principal balance. It can include unpaid fees when that option is selected.
Payoff Balance = Principal Balance + Unpaid Interest + Unpaid Fees
Payments are applied by the selected priority. Common priority is fees first, interest second, and principal last.
For rate changes, interest is calculated at the old rate through the event date. Later rows use the new rate.
How To Use This Calculator
- Enter the original principal, annual rate, start date, and review date.
- Select the day count basis used by your agreement.
- Choose whether unpaid fees should accrue interest.
- Set the payment allocation priority used by your lender.
- Add optional scheduled payments and a first payment date.
- Enter irregular rows in the schedule box.
- Use payment, extra_payment, fee, draw, or rate_change as event types.
- Press calculate and review the result above the form.
- Download CSV or PDF for records.
Advanced Loan Tracking For Uneven Cash Flow
A loan rarely moves in a perfect line. Many borrowers pay early, pay late, skip a month, add fees, or make one large extra payment. This calculator is built for those real schedules. It reads each dated event, applies interest for the exact gap, and then updates the balance. You can compare lender statements, plan a payoff, or test a refinancing idea.
Why Irregular Payments Matter
Irregular payments change interest because time changes interest. A payment made ten days early saves more than the same payment made ten days late. Extra payments reduce future interest. Fees and new draws raise the balance. A rate change can shift every later line. Simple monthly formulas may miss these details. A dated ledger gives a clearer answer.
Practical Uses
Use this tool for personal loans, private notes, business debt, vehicle balances, and short bridge loans. It also helps when a loan has manual payments instead of fixed automatic drafts. Enter the original principal, the start date, the annual rate, and the review date. Then add payment, fee, draw, and rate change rows in the schedule box.
Better Review And Planning
The result table shows days, interest, principal paid, fees, and ending balance. This makes each step easy to audit. You can see which payments mainly covered interest. You can also see when extra payments began lowering principal faster. The summary gives total paid, total interest, total fees, and remaining balance.
Exporting Your Work
Download the CSV file for spreadsheet review. Download the PDF file for a compact record. Keep both with lender emails, receipts, and payoff letters. Because every calculation uses dates, always check that each date matches your payment proof.
Important Limitations
This page gives an estimate. Real lenders may use rounding rules, grace periods, compounding terms, escrow charges, late fees, or servicing policies. Always compare the output with your agreement and official statement before making financial decisions.
Data Entry Tips
Use positive numbers for payments, fees, draws, and new rates. Choose the correct event type. Keep rows in any order; the calculator sorts them by date. Review unusual results by checking one row at a time. Small date errors can create large interest differences.
FAQs
What is an irregular payment?
It is any payment that does not follow the normal amount or date. Extra, missed, early, and late payments are common examples.
Can this calculator handle rate changes?
Yes. Add a rate_change row. The amount should be the new annual rate. Later interest uses that new rate.
Does the calculator include unpaid interest?
Yes. Interest accrues between dated events. Payments reduce it according to the selected allocation priority.
Can I add loan fees?
Yes. Use the fee event type. You can also decide whether unpaid fees should be part of the interest base.
What does draw mean?
A draw adds new borrowed principal. It is useful for lines of credit, construction loans, and private notes.
Why does day count basis matter?
Interest changes when the lender uses 360 days instead of 365 days. Check your loan agreement before choosing.
Can I export the schedule?
Yes. After calculating, use the CSV or PDF buttons above the form. Both exports use the current input values.
Is this a legal payoff quote?
No. It is an estimate for planning and review. Always request an official payoff statement from the lender.