Electrical Load Calculator
Calculate total electrical load vs. panel capacity using the NEC 80% rule.
Quick Add Appliances
Load Items
Central A/C (3-ton)
3500W each
Electric Range
8000W each
Electric Dryer
5000W each
Water Heater
4500W each
Refrigerator
150W each
LED Lighting (per room)
60W each
Add Custom Item
Total Load
21.9 kW
91.3A @ 240V
Panel Load
WITHIN CAPACITY
46% used
80% limit = 38.4 kW
Panel Capacity
48 kW
80% Limit
38.4 kW
Headroom
16.5 kW
Items in List
6 devices
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Frequently Asked Questions
How do I calculate electrical load for a circuit?
Multiply amps × volts to get watts. A 20-amp, 120V circuit handles up to 2,400W (derate to 80% = 1,920W continuous). Add up all device wattages to determine if a circuit can handle the load.
What is the 80% rule in electrical circuits?
The NEC requires circuits to be loaded to no more than 80% of their rated ampacity for continuous loads (3+ hours). A 20A circuit should carry no more than 16A (1,920W at 120V) continuously.
How many watts can a 200-amp panel handle?
A 200A, 240V panel has a maximum capacity of 48,000W. At the 80% continuous-load rule, the practical limit is 38,400W. Most homes use 50–150A total load under normal conditions.