What Is the Resistance and Power for 120V and 1.5A?

120 volts and 1.5 amps gives 80 ohms resistance and 180 watts power. Ohm's Law (V = IR) and the power equation (P = VI) connect all four electrical values. Knowing any two lets you calculate the other two instantly.

120V and 1.5A

80 Ω | 180 W

Voltage (V)120 V

Current (I)1.5 A

Resistance (R)80 Ω

Power (P)180 W

Volts

Amps

Ohms

Watts

180

Formulas & Step-by-Step

Resistance

R = V ÷ I

120 ÷ 1.5 = 80 Ω

Power

P = V × I

120 × 1.5 = 180 W

Verification (alternative formulas)

P = I² × R

1.5² × 80 = 2.25 × 80 = 180 W ✓

P = V² ÷ R

120² ÷ 80 = 14,400 ÷ 80 = 180 W ✓

Circuit Analysis

Heat Dissipation

This circuit dissipates 180 watts of power as heat. In a resistor, all electrical energy at steady state converts to thermal energy. The actual component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve rather than applying a blanket margin.

If You Change the Resistance

Resistance	Current	Power	Change
40 Ω	3 A	360 W	Lower R = more current
60 Ω	2 A	240 W	Lower R = more current
80 Ω	1.5 A	180 W	Current
120 Ω	1 A	120 W	Higher R = less current
160 Ω	0.75 A	90 W	Higher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 80Ω, here is how current and power scale with source voltage. This is a reference table, not a set of separate circuit scenarios: each row is the same resistor under a different applied voltage.

Voltage	Current (at 80Ω)	Power
5V	0.0625 A	0.3125 W
12V	0.15 A	1.8 W
24V	0.3 A	7.2 W
48V	0.6 A	28.8 W
120V	1.5 A	180 W
208V	2.6 A	540.8 W
230V	2.88 A	661.25 W
240V	3 A	720 W
480V	6 A	2,880 W

Related Calculations

bolt 180W to amps at 120V electric_bolt 1.5A to watts at 120V payments 180W running cost functions Ohm's Law formula

Frequently Asked Questions

What is the resistance for 120V and 1.5A?expand_more

R = V ÷ I = 120 ÷ 1.5 = 80 ohms.

How are voltage, current, resistance, and power related?expand_more

Ohm's Law (V = IR) and the power equation (P = VI) connect all four. Given any two, you can calculate the other two.

What is the power for 120V and 1.5A?expand_more

P = V × I = 120 × 1.5 = 180 watts.

What are all 12 Ohm's Law formulas?expand_more

V=IR, V=P/I, V=√(PR) | I=V/R, I=P/V, I=√(P/R) | R=V/I, R=V²/P, R=P/I² | P=VI, P=I²R, P=V²/R.

How much heat does 80 ohms produce at 120V?expand_more

All 180W is dissipated as heat in a pure resistor at steady state. The component power rating needs headroom above this steady-state figure, but the specific derating depends on resistor type (carbon-comp, metal-film, wirewound each behave differently), ambient temperature, airflow or heat-sinking, and whether the load is continuous or pulsed. Check the resistor datasheet for the manufacturer-specific derating curve.

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.