2,500 is the example result. Read it using the units and relationship stated below.
Transformer Sizing uses connected load (va), headroom (%).
Distinguishing electrical arithmetic from equipment selection
For transformer sizing, the relationship is Result = [Connected load (VA)] × (1 + [Headroom (%)] ÷ 100). The amount depends on the supplied connected load (va), headroom (%), 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.
Source and result record
For transformer sizing, retain Connected load (VA), Headroom (%) together with the output. Record the date of the source values and the unit convention used in the form. That record separates a change in the underlying case from a change in how the information was entered. A saved result without its source values cannot show which assumption produced it.
Example with the supplied inputs
Connected load (VA): 2000; Headroom (%): 25. Result: 2,500. The values are illustrative.
Compare one changed input
Connected load (VA) changes from 2000 to 2200. The result becomes 2,750. All other inputs remain fixed.
Calculation rule
Result = [Connected load (VA)] × (1 + [Headroom (%)] ÷ 100)
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Connected load (VA) | 2000 | Use the source quantity represented by connected load (va). Keep the counted population fixed and avoid mixing a unit value with a period total. |
| Headroom (%) | 25 | Enter headroom (%) 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: 2,500 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 Connected load (VA), Headroom (%). 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 Connected load (VA) 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 2,500.
Change Connected load (VA) from 2000 to 2200 while keeping every other value fixed. The result becomes 2,750. 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