Accountants Late Payment Interest Calculator Examples
Worked examples of monthly simple interest on overdue accountancy invoices.
These examples show how the invoice balance, monthly rate and overdue period affect estimated interest and the total amount due.
Small invoice overdue for one month
£800 invoice at 1.5% per month for 1 month.
Input Summary
Balance
£800
Rate
1.5%
Months
1
Calculation Breakdown
- 1Monthly interest£800 × 0.015£12.00
- 2Total due£800 + £12.00£812.00
Result Summary
Total due
£812.00
Accountants Late Payment Interest Calculator
Estimated interest is £12.00 and total due is £812.00.
Larger invoice overdue for six months
£12,000 invoice at 1% per month for 6 months.
Input Summary
Balance
£12,000
Rate
1%
Months
6
Calculation Breakdown
- 1Interest per month£12,000 × 0.01£120.00
- 2Total interest£120.00 × 6£720.00
- 3Total due£12,000 + £720.00£12,720.00
Result Summary
Total due
£12,720.00
Accountants Late Payment Interest Calculator
Estimated interest is £720.00 and total due is £12,720.00.
Higher monthly rate
£3,500 invoice at 2% per month for 4 months.
Input Summary
Balance
£3,500
Rate
2%
Months
4
Calculation Breakdown
- 1Interest per month£3,500 × 0.02£70.00
- 2Total interest£70.00 × 4£280.00
- 3Total due£3,500 + £280.00£3,780.00
Result Summary
Total due
£3,780.00
Accountants Late Payment Interest Calculator
Estimated interest is £280.00 and total due is £3,780.00.
How to Read Your Results
Interest per month shows the charge on the original balance for one month.
Total interest covers the full-month period entered.
Total amount due combines the original balance and estimated interest.
Results are estimates rather than a statement of entitlement.
Assumptions & Important Notes
- The balance is unchanged during the overdue period.
- Interest is simple and applied for complete months only.
- No additional charges are included.
Related Examples
Frequently Asked Questions
Can I use these examples for partial months?
No. The calculator is designed for full months only.
Why does the monthly charge stay the same?
Simple interest is calculated on the original overdue amount.
Are recovery charges included?
No. The examples calculate interest only.
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Use the live calculator with your own inputs, timing, and preferences.