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Penalty and late fee calculator
An instalment was missed. This works out what the borrower owes on top of it under your own rules — how long the grace period runs, what the penalty is charged on, and how often it recurs — and shows every individual charge that makes up the total.
The overdue instalment
Only used when the penalty is charged on the whole balance rather than on the missed instalment.
The date the borrower pays, or today if the arrears are still open.
Days after the due date before any penalty is charged. A payment made on the last day of grace costs nothing extra.
Penalty rules
Charging on the whole outstanding balance rather than the missed instalment produces a far larger penalty, and is restricted or banned in several markets.
Recurring penalties are charged per period or part thereof — a charge falls due the moment a period starts, not when it ends.
Optional ceiling, as a percentage of the amount the penalty is charged on. Leave at 0 for no cap.
Penalty owed
ZAR 179.20
Annualised, that is 31.06%
The penalty restated as a yearly rate on the amount it is charged on, so it can be read next to an interest rate.
- Days late
- 47
- Penalty starts
- Jun 11, 2026
- Chargeable days
- 37
- Charges applied
- 2
- Charged on
- ZAR 4,480.00
- Instalment overdue
- ZAR 4,480.00
- Total penalty
- ZAR 179.20
- Total to clear the arrears
- ZAR 4,659.20
What has to be paid
- Instalment
- Penalty
An estimate for planning and for explaining a figure to a borrower. Your loan agreement, your local rules on penalty interest, and your own rounding decide what is actually enforceable.
Every charge, one by one
Each row is a single penalty charge: the date it falls due, what it was worked out on, and the running total behind it.
Opens in Excel, Sheets or any spreadsheet.
| # | Charge date | Days late | Charged on | Penalty | Running total |
|---|---|---|---|---|---|
| 1 | Jun 11, 2026 | 10 | ZAR 4,480.00 | ZAR 89.60 | ZAR 89.60 |
| 2 | Jul 11, 2026 | 40 | ZAR 4,480.00 | ZAR 89.60 | ZAR 179.20 |
| Total | ZAR 179.20 |
Four settings decide the whole number
Late fee disputes almost always come down to one of these being read differently by the lender and the borrower. Write all four into the agreement.
- 1
When the clock starts
The grace period is the gap between the due date and the first charge. Ten days of grace on a payment that is ten days late means no penalty at all — the charge lands on day eleven. Leaving it undefined is the single most common cause of a late fee being reversed.
- 2
What the charge is measured against
Two percent of a missed instalment and two percent of the outstanding loan balance are wildly different amounts on the same loan. Charging on the whole balance is restricted or prohibited in a number of markets, and it is worth checking before it is written into a product.
- 3
How often it repeats
A one-off charge is fixed the day it is levied. A recurring one keeps growing until the arrears are cleared, which is what turns a small late fee into a debt of its own. Daily penalties on a long-overdue account can outrun the instalment that caused them.
- 4
Whether there is a ceiling
A cap stops the total at a fixed proportion of the debt, however long the account stays open. Several regulators impose one, and without it a forgotten daily penalty eventually produces a figure that is neither collectable nor defensible.
What each cycle does to the total
The same rate, the same instalment, the same 47 days late — only the cycle changes. Charges are levied per period or part thereof, so a charge falls due the moment a period starts.
| Charged | What it means | 2% on a 4,480 instalment, 37 chargeable days |
|---|---|---|
| Once only | A single charge the day the grace period runs out. The amount is fixed from then on, however long the arrears stay open. | 1 charge — 89.60 |
| Every day | Penalty interest in all but name. It accrues without limit, so a cap or a hard collections deadline usually goes with it. | 37 charges — 3,315.20 |
| Every week | A middle ground: the pressure builds week by week, but the total stays comprehensible to the borrower. | 6 charges — 537.60 |
| Every month | The usual choice on monthly instalments, and the easiest to reconcile against a statement, since it moves once per cycle. | 2 charges — 179.20 |
Every one of those totals comes from the same rate on the same instalment. The cycle is not a detail — it is most of the answer.
Amortization Schedule GeneratorQuestions about penalties and late fees
- Take the amount the penalty is charged on — usually the overdue instalment, sometimes only its principal — and apply the agreed rate or flat charge. Then repeat it for every cycle the account stays overdue after the grace period ends. The total is the rate multiplied by the number of charges levied, which is why the cycle matters more than the rate on a long-overdue account.
- It is a fixed number of days after the due date during which no penalty is charged. Nothing obliges a lender to offer one unless local rules or the loan agreement say so, but most do: payment systems clear at different speeds, and a few days of tolerance avoids penalising a borrower for a bank’s timing. Whatever you choose has to be stated in the agreement to be enforceable.
- A percentage stays proportionate across a portfolio — the same rule is fair on a 500 loan and a 500,000 one. A fixed charge is easier for a borrower to understand and easier to collect, but it is punitive on small balances and negligible on large ones. Lenders with a wide range of loan sizes generally use a percentage; those with a narrow one often prefer a flat fee.
- Technically yes, and some agreements do it. It produces a much larger figure than charging on the missed instalment alone, and several jurisdictions restrict or prohibit it, along with capping total penalties at a proportion of the original debt. Check your own regulator before setting it up this way.
- It restates the penalty as a yearly rate on the amount it was charged on, so it can be compared with an interest rate. A two percent charge that sits on the account for 47 days is around 15.5% a year; the same two percent charged monthly is far higher. It is the quickest way to see whether a late fee is a nudge or a second loan.
- Because a recurring charge has no natural end. On a daily cycle the penalty can exceed the instalment that triggered it within a couple of months, and eventually the loan itself. Many regulators impose a ceiling for exactly that reason — often expressed as a percentage of the outstanding debt — and a cap in your own product rules keeps a forgotten account from generating a figure nobody will ever collect.
- In practice they are the same mechanism at different frequencies. Penalty interest is usually a rate accruing daily on the overdue amount; a late fee is usually a one-off or monthly charge. Set this calculator to a daily cycle and you are modelling penalty interest; set it to once and you are modelling a late fee.
- Yes. Penalty income is not interest income, and mixing the two distorts your yield on the portfolio and, in most frameworks, is reported incorrectly. It should post to its own income account, which is how Lendbox handles it when a penalty is charged against a loan.
- No. The whole calculation runs in your browser, and the exports are generated on your own device. Nothing you type is sent to a server, saved, or logged, and there is no sign-up.
How is a late payment penalty calculated?
What is a grace period, and does it have to be given?
Should the penalty be a percentage or a fixed amount?
Can a penalty be charged on the whole outstanding balance?
What does the annualised figure mean?
Why should a penalty be capped?
Is penalty interest the same as a late fee?
Do penalties have to be accounted for separately?
Is my data stored?
Stop working out arrears by hand
Lendbox applies your penalty rules automatically the day an instalment falls overdue — grace period, basis, cycle and cap — posts the charge to its own income account, and shows collections exactly what each borrower owes today.
No credit card required.
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