What Is the Resistance and Power for 24V and 5A?

With 24 volts across a 4.8-ohm load, 5 amps flow and 120 watts are dissipated. These four values (voltage, current, resistance, and power) are the foundation of every electrical calculation on this site.

24V and 5A

4.8 Ω | 120 W

Voltage (V)24 V

Current (I)5 A

Resistance (R)4.8 Ω

Power (P)120 W

Volts

Amps

Ohms

4.8

Watts

120

Formulas & Step-by-Step

Resistance

R = V ÷ I

24 ÷ 5 = 4.8 Ω

Power

P = V × I

24 × 5 = 120 W

Verification (alternative formulas)

P = I² × R

5² × 4.8 = 25 × 4.8 = 120 W ✓

P = V² ÷ R

24² ÷ 4.8 = 576 ÷ 4.8 = 120 W ✓

Circuit Analysis

Heat Dissipation

This circuit dissipates 120 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
2.4 Ω	10 A	240 W	Lower R = more current
3.6 Ω	6.67 A	160 W	Lower R = more current
4.8 Ω	5 A	120 W	Current
7.2 Ω	3.33 A	80 W	Higher R = less current
9.6 Ω	2.5 A	60 W	Higher R = less current

Same Resistance at Different Voltages

Holding the resistance constant at 4.8Ω, 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 4.8Ω)	Power
5V	1.04 A	5.21 W
12V	2.5 A	30 W
24V	5 A	120 W
48V	10 A	480 W
120V	25 A	3,000 W
208V	43.33 A	9,013.33 W
230V	47.92 A	11,020.83 W
240V	50 A	12,000 W
480V	100 A	48,000 W

Related Calculations

bolt 120W to amps at 24V electric_bolt 5A to watts at 24V payments 120W running cost cable Wire size for 5A at 24V functions Ohm's Law formula

Frequently Asked Questions

What is the resistance for 24V and 5A?expand_more

R = V ÷ I = 24 ÷ 5 = 4.8 ohms.

Does Ohm's Law work for AC circuits?expand_more

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.

What determines wire size for 5A?expand_more

Wire sizing for a given current is not an Ohm's Law calculation. It depends on run length, source voltage, voltage-drop target, conductor material, insulation and termination temperature rating, cable type, and ambient and bundling conditions. The dedicated wire-size calculator takes those variables as input.

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 happens if I halve the resistance?expand_more

At the same 24V, current doubles to 10A and power quadruples to 240W. Lower resistance means more current, which means more power dissipated as heat.

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.