Business
Invoice late-payment interest Calculator
Calculate simple overdue interest using the applicable entered rate and compensation. This free invoice late-payment interest calculator shows the calculation and its assumptions so you can compare your own figures.
Your results
Calculate simple overdue interest using the applicable entered rate and compensation.
Calculated outcomes
- Compensation
- €0.00
Assumptions and estimates
- Simple actual-days/365 interest. Enter the legally applicable or agreed rate and any applicable fixed compensation. This calculator does not decide entitlement or model payments made partway through the overdue period.
- Method: Simple interest = outstanding principal × entered annual rate × days overdue ÷ 365; entered compensation is added.
- This arithmetic does not determine legal entitlement. Part-period payments require separate period calculations.
Useful next steps
- Use Compare options to test an alternative side by side.
- Copy, print or download a record of this calculation when you need one.
Reports open your email app addressed to s@s1.ie with the public page address only. Your inputs are never added.
How the invoice late-payment interest calculation works
Simple interest = outstanding principal × entered annual rate × days overdue ÷ 365; entered compensation is added.
This arithmetic does not determine legal entitlement. Part-period payments require separate period calculations.
Using this calculator
- Enter your own figures in the labelled inputs. Keep the currencies, units and time periods consistent.
- Choose any applicable rate profile, pattern or assumption shown for this tool. Open additional inputs when relevant.
- Review late interest and outstanding principal and total due, then read the stated assumptions and eligibility conditions before using the result.
Worked example
This is a static example using illustrative inputs, not facts about you or today’s date. The displayed eligibility selections and assumptions apply only to this example.
See example inputs
- Original invoice principal (€)
- 5000
- Applicable annual interest rate (%)
- 0
- Days overdue
- 60
- Applicable fixed compensation (€)
- 0
- Payments already received (€)
- 0
- Late Interest
- €0.00
- Outstanding Principal
- €5,000.00
- Total Due
- €5,000.00