THE NUMBERS, EXPLAINED
How to use this calculator.
Overage is rounded separately from the base rental. Meter readings are already reconciled and all fee rules are supplied.
Start with your inputs
Enter actual metered rental runtime (hours), included runtime (hours), overage billing increment (hours), price per excess hour (currency), base rental charge (currency). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Actual metered rental runtime (hours) | 35 |
| Included runtime (hours) | 20 |
| Overage billing increment (hours) | 0.5 |
| Price per excess hour (currency) | 8 |
| Base rental charge (currency) | 200 |
A worked example
With the example inputs above, raw excess runtime (hours) is 15. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Raw excess runtime (hours) | 15 |
| Billable excess runtime (hours) | 15 |
| Total invoice (currency) | 320 |
How this is calculated
Raw excess runtime (hours)
Deduct included runtime from actual usage.
Billable excess runtime (hours)
Round excess runtime up to the supplied billing increment.
Total invoice (currency)
Add priced excess runtime to the base rental.
Symbols and units
- a
- Actual metered rental runtime (hours)
- b
- Included runtime (hours)
- c
- Overage billing increment (hours)
- d
- Price per excess hour (currency)
- e
- Base rental charge (currency)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Overage is rounded separately from the base rental. Meter readings are already reconciled and all fee rules are supplied.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Raw excess runtime (hours); Billable excess runtime (hours); Total invoice (currency). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Overage is rounded separately from the base rental. Meter readings are already reconciled and all fee rules are supplied.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: Describe and Identify Cost Drivers ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →