What Is the Resistance and Power for 24V and 1A?

Using Ohm's Law: 24V at 1A means 24 ohms of resistance and 24 watts of power. This is useful for sizing resistors, understanding circuit behavior, and verifying that components can handle the power dissipation (24W in this case).

24V and 1A
24 Ω   |   24 W
Voltage (V)24 V
Current (I)1 A
Resistance (R)24 Ω
Power (P)24 W
24
24

Formulas & Step-by-Step

Resistance

R = V ÷ I

24 ÷ 1 = 24 Ω

Power

P = V × I

24 × 1 = 24 W

Verification (alternative formulas)

P = I² × R

1² × 24 = 1 × 24 = 24 W

P = V² ÷ R

24² ÷ 24 = 576 ÷ 24 = 24 W

Circuit Analysis

Heat Dissipation

This circuit dissipates 24 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

ResistanceCurrentPowerChange
12 Ω2 A48 WLower R = more current
18 Ω1.33 A32 WLower R = more current
24 Ω1 A24 WCurrent
36 Ω0.6667 A16 WHigher R = less current
48 Ω0.5 A12 WHigher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 24Ω, 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.

VoltageCurrent (at 24Ω)Power
5V0.2083 A1.04 W
12V0.5 A6 W
24V1 A24 W
48V2 A96 W
120V5 A600 W
208V8.67 A1,802.67 W
230V9.58 A2,204.17 W
240V10 A2,400 W
480V20 A9,600 W

Frequently Asked Questions

R = V ÷ I = 24 ÷ 1 = 24 ohms.
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.
Ohm's Law (V = IR) and the power equation (P = VI) connect all four. Given any two, you can calculate the other two.
For purely resistive loads, yes. For reactive loads, use impedance (Z) instead of resistance (R). Z includes both resistance and reactance, and the V/I phase shift shows up in power factor.
P = V × I = 24 × 1 = 24 watts.
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.