Inverter Size Calculator
This free inverter size calculator helps you determine the correct inverter capacity based on your total electrical load.Enter the wattage of appliances you want to run to calculate the required inverter size in VA or kVA for home backup or solar systems.
Inverter Size Calculator
Choosing the correct inverter size for your home is very important. A small inverter may trip frequently, while an oversized inverter increases cost unnecessarily.
This guide helps you calculate the exact inverter size based on your appliance load using a simple formula.
To calculate inverter size, add total watt load of appliances, multiply by 1.2 safety factor, and divide by 0.8 power factor to get required VA rating.
Formula:
Required VA = (Total Watt Load × 1.2) ÷ 0.8
How to Calculate Inverter Size Step by Step
Step 1: Calculate Total Watt Load
Add wattage of all appliances you want to run during power cut.
Example:
TV = 150W
Fan (2 units) = 150W
Lights (4 units) = 40W
Laptop = 100W
Total Load = 440W
Step 2: Add Safety Factor
440 × 1.2 = 528W
Step 3: Convert Watt to VA
528 ÷ 0.8 = 660 VARecommended inverter size = 800VA
Recommended Inverter Size by Home Type
| Home Type | Approx Load | Recommended Inverter |
| 1 Room | 300–400W | 600VA |
| 2 Room | 500–700W | 800VA |
| Small Home | 800–1000W | 1kVA |
| With AC | 1500W+ | 2kVA+ |
Inverter Size for 1.5 Ton AC
1.5 Ton AC consumes around 1500W.
1500 × 1.2 = 1800W
1800 ÷ 0.8 = 2250 VA
Minimum recommended inverter: 2.5kVA.
Difference Between Watt and VA
Watt (W) is real power.VA (Volt-Ampere) is apparent power.
Formula:VA = Watt ÷ Power Factor
In India, power factor is usually 0.8.
Inverter Size Formula
Inverter Size (VA) = Total Load (Watts) ÷ Power Factor
Who Should Use This Calculator
- Homeowners selecting inverter size
- Users upgrading inverter systems
- Solar system planners
- Beginners avoiding under- or over-sizing
Important Note
Calculated inverter size is an estimate. Always consult a professional installer before final purchase.
FAQs
How do I know which inverter size is best?
Calculate total load and apply safety factor.
How do I calculate total load for inverter?
Add the wattage of all appliances you want to run simultaneously.
What is power factor in inverter?
Power factor represents efficiency. Most home inverters use a power factor of 0.8.
Is a higher inverter size better?
Yes, choosing a slightly higher inverter capacity ensures smooth operation and future expansion.
Is this inverter calculator free to use?
Yes, this inverter size calculator is completely free.
Can 800VA inverter run refrigerator?
Yes, if total load is within limit.
What inverter size is needed for 2BHK house?
Usually 1kVA to 1.5kVA.
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Disclaimer:
Inverter size suggestions from this calculator are estimates based on input values.
Always consult a qualified professional before purchasing or installing an inverter.