Electrical Load Calculator
Sums watt loads, divides by volts for amps, then multiplies by a continuous factor (default 1.25).
Limitation: Educational estimate only.
How to Use the Electrical Load Calculator
Enter the fields below, then review the educational estimate.
Enter circuit voltage.
Diversity & demand
Homes rarely run every load at once. This worksheet does not apply demand factors—it sums what you enter.
What This Calculator Estimates
Simple arithmetic load list for teaching circuit current before breaker/wire coordination.
Worked Examples
1500 W + 600 W on 120 V
Inputs
Result
2100 W / 120 = 17.5 A; ×1.25 = 21.875 A.
Safety first
De-energize circuits before measuring. When in doubt, stop and consult a licensed electrician.
Frequently Asked Questions
Still have questions about this calculation?
Try the CalculatorFormulas & Assumptions
Transparent educational arithmetic. Not NEC design software or a wiring permit.
Formula
Total power
Wtotal = W1 + W2 + W3 + W4
Amps & design
I = Wtotal / V; Idesign = I × factor
Scientific Background
Service and feeder calculations in code use occupancy-specific demand factors far beyond a four-line watt list. Pair results with breaker and wire worksheets only as learning tools.
Sources & review
Electrical Load Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.
Last reviewed
July 22, 2026
Reference
physics.nist.gov
https://physics.nist.gov/cuu/Constants/index.htmlReference
nist.gov
https://www.nist.gov/pml/owm/wire-gauge-and-current-carrying-capacityFree Calculator Hub methodology
Free Calculator Hub
/methodology
See our methodology and corrections policy.