swap_horiz Looking to convert 20A at 240V back to watts?

How Many Amps Is 4,800 Watts at 240V?

4,800 watts equals 20 amps at 240V on an AC single-phase resistive circuit (PF 1.0). AC resistive at PF 1.0 and the DC baseline land on the same number at this voltage.

At 20A, the NEC 210.19(A) continuous-load sizing math (125% of the load, equivalently 80% of the breaker rating) points to a 25A breaker as the smallest standard size that covers this load continuously. A 20A breaker is the smallest standard size the raw current fits under, but it is non-continuous-only at this load. At 240V, the lower current draw allows smaller wire and breakers compared to 120V.

4,800 watts at 240V

20 Amps

4,800 watts equals 20 amps at 240 volts (AC single-phase, PF 1.0 resistive)

DC20 A

Try: 5,000W at 240V 4,500W at 240V 4,000W at 240V 6,000W at 240V

Watts

Volts

Amps (AC 1Φ, PF 1.0)

Assumes an AC single-phase resistive load at PF 1.0. Typing a commercial L-L voltage (208/400/480V) re-routes the result to three-phase; 277V stays on single-phase because it's the L-N lighting leg of a 480Y/277V wye; 12/24V re-routes to DC.

Formulas

DC: Watts to Amps

I_(A) = P_(W) ÷ V_(V)

4,800 ÷ 240 = 20 A

AC Single Phase (PF = 0.85)

I_(A) = P_(W) ÷ (PF × V_(V))

4,800 ÷ (0.85 × 240) = 4,800 ÷ 204 = 23.53 A

Circuit Sizing

Breaker Sizing

NEC 240.6(A) standard ampere ratings for branch-circuit and feeder breakers start at 15, 20, 25, 30, 35, 40, 45, and 50A and continue at 60A and above for feeder and large-appliance circuits. At 20A, the smallest standard breaker the raw current fits under is 20A, but that breaker only covers 20A non-continuously; NEC 210.19(A) requires conductor and OCP sized at 125% of any continuous load (equivalently 80% of breaker rating), so for a continuous load the smallest compliant breaker is 25A. Final selection still depends on the equipment nameplate, whether the load is continuous, conductor ampacity, and local code.

Breaker Size	Max Continuous Load (80%)	Status for 20A
15A	12A	Too small
20A	16A	Non-continuous only
25A	20A	OK for continuous
30A	24A	OK for continuous
35A	28A	OK for continuous
40A	32A	OK for continuous
45A	36A	OK for continuous
50A	40A	OK for continuous

Energy Cost

Running 4,800W costs approximately $0.82 per hour at the US average rate of $0.17/kWh (rates last reviewed April 2026). That is $6.53 for 8 hours or about $195.84 per month. See detailed cost breakdown.

AC Conversion Detail

The DC baseline for 4,800W at 240V is 20A. On an AC circuit with a power factor of 0.85, the current rises to 23.53A because reactive current flows alongside the real-power current.

Circuit Type	Formula	Result
DC	4,800 ÷ 240	20 A
AC Single Phase (PF 0.85)	4,800 ÷ (240 × 0.85)	23.53 A

Power Factor Reference

Power factor is the main reason 4,800W draws more current on AC than DC. At PF 1.0 (pure resistive, like a heater), the load pulls 20A at 240V on the single-phase basis the rest of the page uses. At PF 0.80 (typical induction motor), the same 4,800W pulls 25A. That is an extra 5A just to overcome the reactive component. Use the typical values below as a starting point, not for precise engineering calculations.

Load Type	Typical PF	4,800W at 240V (single-phase)
Resistive (heaters, incandescent)	1	20 A
Fluorescent lamps	0.95	21.05 A
LED lighting	0.9	22.22 A
Synchronous motors	0.9	22.22 A
Typical mixed loads	0.85	23.53 A
Induction motors (full load)	0.8	25 A
Computers (without PFC)	0.65	30.77 A
Induction motors (no load)	0.35	57.14 A

Same Wattage, Other Voltages

bolt4,800W at 12V = 400ADC bolt4,800W at 24V = 200ADC bolt4,800W at 100V = 48A1Φ, PF 1.0 bolt4,800W at 120V = 40A1Φ, PF 1.0 bolt4,800W at 208V = 15.67A3Φ per line, PF 0.85 bolt4,800W at 220V = 21.82A1Φ, PF 1.0 bolt4,800W at 230V = 20.87A1Φ, PF 1.0 bolt4,800W at 277V = 17.33A1Φ, PF 1.0 bolt4,800W at 400V = 8.15A3Φ per line, PF 0.85 bolt4,800W at 460V = 7.09A3Φ per line, PF 0.85 bolt4,800W at 480V = 6.79A3Φ per line, PF 0.85 bolt4,800W at 575V = 5.67A3Φ per line, PF 0.85

swap_horiz 20A to watts at 240V payments 4,800W running cost cable Wire size for 20A at 240V electrical_services 4.8 kW to amps science Ohm's law: 240V & 20A functions Watts to amps formula

Other Wattages at 240V

Watts	AC 1Φ Amps PF 1.0 resistive	AC 1Φ Amps PF 0.85 motor
1,300W	5.42A	6.37A
1,400W	5.83A	6.86A
1,500W	6.25A	7.35A
1,600W	6.67A	7.84A
1,700W	7.08A	8.33A
1,800W	7.5A	8.82A
1,900W	7.92A	9.31A
2,000W	8.33A	9.8A
2,200W	9.17A	10.78A
2,400W	10A	11.76A
2,500W	10.42A	12.25A
2,700W	11.25A	13.24A
3,000W	12.5A	14.71A
3,500W	14.58A	17.16A
4,000W	16.67A	19.61A
4,500W	18.75A	22.06A
5,000W	20.83A	24.51A
6,000W	25A	29.41A
7,500W	31.25A	36.76A
8,000W	33.33A	39.22A

Frequently Asked Questions

How many amps is 4,800W at 240V? expand_more

4,800W at 240V draws 20 amps on AC single-phase at PF 1.0 (resistive). For comparison at the same voltage: 20A on DC, 23.53A on AC single-phase at PF 0.85. Actual current depends on the load's power factor.

How much does 4,800W cost to run per hour? expand_more

At the US residential average of $0.17/kWh (last reviewed April 2026), 4,800W costs $0.82 per hour and $6.53 for 8 hours. Rates vary by utility and time of day.

What kind of 240V outlet does a 4,800W appliance need? expand_more

At US 240V a "regular outlet" is not a standard 120V NEMA 5-15R household receptacle, it's a dedicated 240V branch-circuit receptacle sized to the load. At 4,800W on 240V the current is 20A, which typically maps to a NEMA 6-30 or 14-30 receptacle on a 240V/30A circuit (14-30 is the modern dryer outlet). Receptacle choice also depends on whether a neutral is needed, the equipment's cord and plug configuration, and any local amendments. Verify against the appliance's spec sheet and the receiving circuit.

Why does AC draw more amps than DC for 4,800W? expand_more

AC circuits with reactive loads have a power factor below 1.0, so they draw extra current. At PF 0.85, 4,800W at 240V draws 23.53A instead of 20A (DC). That is about 18% more current for the same real power.

Why does a 4,800W resistive heater draw fewer amps than a 4,800W motor at 240V? expand_more

Resistive loads like space heaters and toasters have a power factor of 1.0, so 4,800W at 240V on a single-phase AC basis draws 20A. An induction motor at the same wattage has a PF around 0.80, drawing 25A on the same basis. The extra current is reactive, it does no real work but still has to flow through the conductors and breaker.

This calculator provides estimates for reference purposes only. Always consult a licensed electrician and verify compliance with the National Electrical Code (NEC) and local electrical codes before performing any electrical work.