22.5 is the example result. Read it using the units and relationship stated below.
Motor Breaker Size uses load current (a), sizing multiplier (%).
Distinguishing electrical arithmetic from equipment selection
For motor breaker size, the relationship is Result = [Load current (A)] × [Sizing multiplier (%)] ÷ 100. The amount depends on the supplied load current (a), sizing multiplier (%), rather than a live market price or a value imported from another record. Power, energy, voltage and current describe different quantities. Watts represent a rate; watt-hours represent energy over time. Battery and inverter losses can reduce usable runtime even when the rated capacity is unchanged.
What the model includes
Result = [Load current (A)] × [Sizing multiplier (%)] ÷ 100 Read unit labels before comparing results. Motor estimates depend on phase, efficiency and power factor; energy budgets depend on duration and duty cycle. Nameplate values and measured consumption may differ under real loads. Treat the output as the stated estimate. It does not select a code-compliant conductor, protective device or complete installation. Equipment specifications and applicable requirements remain part of the design decision.
Example with the supplied inputs
Load current (A): 18; Sizing multiplier (%): 125. Result: 22.5. The values are illustrative.
Compare one changed input
Load current (A) changes from 18 to 19.8. The result becomes 24.75. All other inputs remain fixed.
Calculation rule
Result = [Load current (A)] × [Sizing multiplier (%)] ÷ 100
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Load current (A) | 18 | Use the source quantity represented by load current (a). Keep the counted population fixed and avoid mixing a unit value with a period total. |
| Sizing multiplier (%) | 125 | Enter sizing multiplier (%) on the percentage scale used in the formula (20 means 20%, not 0.20). Keep its base and reporting period consistent with the other inputs. |
Output: 22.5 is the example result. Read it using the units and relationship stated below. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Load current (A), Sizing multiplier (%). Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change Load current (A) on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 22.5.
Change Load current (A) from 18 to 19.8 while keeping every other value fixed. The result becomes 24.75. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026