Amps, Watts, Volts, kVA & kWh Power Converter, NEC Wire Ampacity & LED Calculator

Convert Amps, Volts, Watts, kW, kVA & HP, size NEC 75°C copper wire gauge, and compute kWh cost & LED resistors.

Real Power (Watts / kW) & Apparent Power (kVA)
6480 W (6.48 kW / 7.2 kVA)
NEC 125% Wire Size: 8 AWG / 6 AWG Copper (40–50A Breaker) • Monthly Energy: 1166.4 kWh ($186.62/mo)
Apparent Power & Horsepower 7.2 kVA • 8.69 HP
NEC Copper Wire & Breaker (125%) 8 AWG / 6 AWG Copper (40–50A Breaker)
Monthly Energy (6 hrs/day) 1166.4 kWh ($186.62/mo)
LED Current-Limiting Resistor 495 Ω (0.198 W)
Inputs
Select DC, Single-Phase AC, or Three-Phase AC.
V
Common voltages: 12V/24V/48V DC, 120V/240V 1Φ AC, 208V/415V/480V 3Φ AC.
A
Continuous or peak load current in Amps.
PF
Resistive heaters = 1.0; induction motors/compressors ≈ 0.80–0.92.
hrs/day
Used to compute daily/monthly kWh consumption and utility cost.
USD / kWh
Cost per kilowatt-hour on your utility bill.
V DC
DC supply voltage for LED resistor calculation.
V
Red/Amber LED ≈ 1.8–2.1V; Blue/White/Green LED ≈ 3.0–3.4V.
mA
Standard indicator LED forward current is 15–20 mA.
Results & Graph
Real Power (Watts / kW) & Apparent Power (kVA)
6480 W (6.48 kW / 7.2 kVA)
NEC 125% Wire Size: 8 AWG / 6 AWG Copper (40–50A Breaker) • Monthly Energy: 1166.4 kWh ($186.62/mo)
Apparent Power & Horsepower
7.2 kVA • 8.69 HP
Power Factor: 0.90
NEC Copper Wire & Breaker (125%)
8 AWG / 6 AWG Copper (40–50A Breaker)
Continuous design load: 37.5 A
Monthly Energy (6 hrs/day)
1166.4 kWh ($186.62/mo)
Annual: $2,239.49/yr
LED Current-Limiting Resistor
495 Ω (0.198 W)
Use ≥ 0.4 W rated resistor

AC Power Triangle, NEC Copper Ampacity Ladder & kWh Cost Suite

Real Active Power (W), Apparent Power (VA), and NEC Conductor Ampacity
Graph 1 • Annotated Electrical Circuit & Power Readout Live Voltage (V), Current (A), Impedance (Ω), and Active Power (W)
240V I = 30 A 6480 W 8.0 Ω Circuit Operating Point • Real Power: 6480 W (6.48 kW) • Apparent Power: 7.20 kVA • NEC 125% Continuous: 37.5 A • Horsepower Eq.: 8.69 HP
Graph 2 • NEC Table 310.16 Copper Wire Gauge Ladder (75°C) Highlights conductor required for 37.5A (125% continuous load)
14 AWG Copper (15A Max Breaker) 15 A 12 AWG Copper (20A Max Breaker) 20 A 10 AWG Copper (30A Max Breaker) 30 A 8 AWG Copper (50A @ 75°C THHN) 50 A 6 AWG Copper (65A @ 75°C THHN) 65 A 4 AWG Copper (85A @ 75°C THHN) 85 A
Graph 3 • Voltage Drop (%) Across Wire Distances (25 ft to 250 ft) Keep branch-circuit voltage drop below the 3.0% NEC recommendation
0% 4.3% 8.5% NEC 3.0% Max Branch-Circuit Drop Limit 25 ft: 0.79 % 0.8 25 ft 50 ft: 1.57 % 1.6 50 ft 100 ft: 3.15 % 3.1 100 ft 150 ft: 4.72 % 4.7 150 ft 200 ft: 6.3 % 6.3 200 ft 250 ft: 7.88 % 7.9 250 ft
Summary: Real power is 6480 W (6.48 kW), apparent power is 7.2 kVA, and monthly electricity cost is $186.62.
Summary: At 240 V and 30 A (Single-Phase AC, PF = 0.9), apparent power is 7200 VA (7.2 kVA) and real power is 6480 W (6.48 kW or 8.69 electrical HP). Sizing for a 125% NEC continuous load (37.5 A) calls for 8 AWG / 6 AWG Copper (40–50A Breaker). Running 6 hours/day consumes 1166.4 kWh/month ($186.62/month).

Formula & Mathematical Methodology: DC / 1Φ / 3Φ Power Identities, kWh Energy & LED Dropping Resistor

P1Φ = V · I · PF,   P3Φ = 3 · VLL · I · PF,   kVA = V · I1000,   RLED = Vs − VfILED
P_1Φ = V × I × PF; P_3Φ = √3 × V_LL × I × PF; kVA = VA / 1000; R_LED = (V_s − V_f) / I_LED
  • √3: Three-phase line-to-line multiplier (≈ 1.73205)
  • PF: Power Factor = Real Power (kW) ÷ Apparent Power (kVA)

Rounding: Power and energy round to 1–2 decimal places; resistor dissipation rounds to 3 decimal places.

Worked Example: 240V Single-Phase 30A Load (PF = 0.90) Running 6 Hours/Day at $0.16/kWh

Find real power, kVA, NEC copper wire size, and monthly operating cost.

  1. Apparent Power = 240 × 30 = 7,200 VA (7.20 kVA); Real Power = 7,200 × 0.90 = 6,480 W (6.48 kW = 8.69 HP).
  2. NEC 125% continuous load = 30 × 1.25 = 37.5 A → Requires 8 AWG Copper on a 40A breaker.
  3. Monthly energy = 6.48 kW × 6 hrs × 30 days = 1,166.4 kWh → Cost = $186.62/month.
Result: 6,480 W (6.48 kW / 7.20 kVA), 8 AWG copper conductor, and $186.62/mo electricity cost.

Frequently Asked Questions

What is the difference between kW (Kilowatts) and kVA (Kilovolt-Amperes)?

kW is Real Power that performs actual work or generates heat. kVA is Apparent Power (Volts × Amps ÷ 1,000), which includes reactive current required to magnetize AC motors and transformers. They are related by kW = kVA × Power Factor.

Why does the National Electrical Code require sizing breakers and wire at 125% of continuous load?

Any electrical load that runs uninterrupted for 3 hours or more (such as EV chargers, water heaters, or commercial lighting) builds up thermal heat in breaker contacts and conductor insulation, requiring a 125% ampacity buffer (or 80% breaker loading rule).

Science & Engineering • Electrical Engineering & Power Systems Guide

How to Use the Amps, Watts, Volts, kVA & kWh Power Converter, NEC Wire Ampacity & LED Calculator: Practical Guide & Visual Analysis

Solve DC, Single-Phase AC, and 3-Phase AC power equations (Amps ↔ Watts ↔ Volts ↔ kVA ↔ HP), check recommended NEC Table 310.16 copper conductor AWG for 125% continuous loads, project monthly appliance kWh electricity bills, and size current-limiting LED resistors. Whether you are researching amps to watts calculator, watts to amps calculator, volts to watts calculator, kva to kw calculator, wire size ampacity calculator, this interactive tool helps you convert between Amps, Volts, Watts, kW, VA, kVA, and electrical Horsepower for DC, Single-Phase AC, and 3-Phase AC circuits, size NEC 125% continuous-load copper wire gauge, estimate monthly kWh electricity cost, and calculate LED series resistors.

Interpreting the 3 Custom Visual Graphs & Key Outputs

As you adjust Circuit Current Type, Circuit Voltage (Volts), Load Current (Amperes), AC Power Factor (PF cos φ), the calculator immediately computes Real Active Power (Watts & kW) and Apparent Power (VA & kVA), Electrical Horsepower Equivalent (1 HP = 745.7 W), Recommended NEC 75°C Copper Wire Gauge (125% Continuous Load), Monthly Energy Consumption (kWh) & LED Series Resistor (Ω & Watts) and updates all three domain-specific SVG charts in real time. Instead of relying on a single static figure, you can inspect the primary domain diagram, component breakdown, and multi-point trajectory curve to see how changing your inputs shifts the final result. Use the Compare (up to 3 scenarios) button to evaluate side-by-side variations before making a decision.

Real-World Benchmark & Planning Tips (Global Electrical Engineering & NFPA 70 (NEC) Reference)

In our benchmark scenario (240V Single-Phase 30A Load (PF = 0.90) Running 6 Hours/Day at $0.16/kWh), 6,480 W (6.48 kW / 7.20 kVA), 8 AWG copper conductor, and $186.62/mo electricity cost. Keep in mind that nEC conductor recommendations reference Table 310.16 (75°C copper THHN/THWN-2) with the mandatory 125% continuous-load multiplier and 14/12/10 AWG small-conductor overcurrent rules (NEC 240.4(D)). For related calculations in Science & Engineering, explore Ohm's Law, Wire Voltage Drop & Resistor Series/Parallel Calculator, EV Charging Cost & Fuel vs. Electricity Calculator, Unit Conversion Calculator.