Watts to Amps Calculator
LED Lighting Supply’s free Watts to Amps Calculator makes it easy for electrical contractors to quickly convert between watts, amps, and volts. The output helps you size components properly, reduce risk, and keep projects on schedule. To use our watts to amps calculator, watts and voltage must be entered as inputs.
Power (W)
Voltage (V)
Current
How to Use LED Lighting Supply's Free Watts to Amps Calculator
Determine power in watts (W) and enter your value into the calculator. A watt (W) is the SI unit (International System of Units) measurement of electrical power. It represents how quickly energy is transferred in a circuit.
Determine voltage (V) and enter your value into the calculator. Voltage represents the electrical potential difference or pressure that pushes current through a circuit.
You can enter in direct current (DC) voltage and alternating current (AC) voltage if the power factor (PF) is 1. Otherwise, the AC voltage should be adjusted. You can find the typical PF and formula below in the Typical Power Factor in Lighting Table and formula section.
Click Calculate to see the conversion from watts and volts to amps. Amps (A) is a measurement of electric charge or the strength of an electric current. Amps represent the flow of electricity through a conductor, and are vital for sizing wires and ensuring safe current flow. A higher amperage reflects a greater volume of electrical charge moving through the system, which directly affects component sizing and wire selection.
Frequently Asked Questions
Why Use Our Watts to Amps Calculator?
Based on feedback from our industrial customers, our calculator helped select the proper wire gauge for the electrical system and ensure your electrical devices are properly sized. These choices prevent potential safety hazards during installation. This tool also serves as a watts calculator, helping you understand power output based on voltage and current input.
What is the Relationship Between Watts, Volts, and Amperage?
A common analogy is to compare an electrical circuit to water flowing through a hose: volts act like water pressure in a pipe, pushing electrons through a conductor just like water flows through a hose. Volts measure the pressure, amperage is like the flow rate, and the wire is the hose.
Higher voltage pushes more current through the conductor just like higher water pressure increases flow through a hose, assuming resistance stays the same.
Watts to Amps Table
This table calculates current in amps and milliamperes using power and voltage. These values assume a power factor of 1 and linear load conditions.
|
Power (W) |
Voltage (V) |
Current (A) |
Current (mA) |
|
1 |
1 |
1 |
1000 |
|
10 |
10 |
1 |
1000 |
|
20 |
10 |
2 |
2000 |
|
50 |
50 |
1 |
1000 |
|
100 |
100 |
1 |
1000 |
|
1000 |
100 |
10 |
10000 |
|
2000 |
200 |
10 |
10000 |
|
5000 |
500 |
10 |
10000 |
|
10000 |
1000 |
10 |
10000 |
Introduction to Electrical Calculations
Understanding how to perform electrical calculations is one of the most fundamental skills every electrician should master. These calculations allow you to determine the relationship between watts, amps, and volts. By mastering these relationships, you can ensure that your electrical installations are safe, efficient, and meet the required performance standards.
When you perform electrical calculations, you’re essentially working with formulas that help you determine how much current (measured in amperes) will flow through a circuit for a given voltage and power. This is crucial for selecting the right components, such as wire size and circuit breakers, and preventing overheating or energy loss issues.
Watts to Amps (A) Conversion Formula:
The formula to convert between watts and amps varies depending on current type (either AC or DC) and the system configuration. Both AC and DC watts are the same since a watt is a standard unit that can represent power in different forms of electrical current. The voltage, however, affects current differently for each system.
Direct Current (DC) Systems
To calculate amps in a DC system, use our watts to amps calculator above or manually calculate using the wattage and voltage to amps formula below:
- Amps = Watts (W) / Volts (V)
Alternating Current (AC) Systems
For AC systems, you have to account for the power factor in the equation since the power put into the system is not always the same power used to light a bulb or run a motor.
The power factor is the ratio of real power to apparent power and measures how efficiently electrical power is being used.
- Real power is the energy used to do useful things, like powering a fan
- Reactive power is the power stored and returned by the inductive and capacitive components of the system
Apparent power is the sum of real and reactive power
How is power factor calculated? Use the formulas or table below to calculate the power factor:
- Power Factor = Real Power / Apparent Power
- Apparent Power = Real Power + Reactive Power
How do you calculate amps from watts to voltage in a single-phase AC system? Use the following formula to calculate amps (A) from watts (W) and voltage (V):
- Amps (A) = Watts (W) / (Volts (V) × Power Factor)
How do you calculate amps from watts to voltage for line-to-line three-phase systems? Use the formula below to convert watts (W) and voltage (V) to current in amps (A):
- Amps (A) = Watts (W) / (√3 × Volts (V) × Power Factor)
For example, a three-phase system with line-to-line voltage of 208 V, power = 10,000 W, and PF = 0.9: Amps = 10000 ÷ (√3 × 208 × 0.9) ≈ 30.8 A
How do you calculate amps from watts to voltage for line-to-neutral three-phase systems? Use the formula below to convert watts (W) and voltage (V) to current in amps (A):
- Amps (A) = Watts (W) / (3 × Volts (V) × Power Factor)
For example, a three phase system with a line-to-neutral voltage of 120 Volts, power = 4,050 W, andPF = 0.9: Amps = 4050 ÷ (3 × 120 × 0.9) = 12.5 A.
TYPICAL POWER FACTORS IN LIGHTING
Why is power factor important? The power factor of a lighting system affects how much current it draws in AC applications. Power factor influences energy efficiency and cost savings.
Our Product Experts have put together typical power factors based on fixture type. To ensure the proper power factor for your fixture type, always consult with a Product Expert. Our Product Specialists will provide live help to determine
|
Fixture Type |
Typical Power Factor |
|
Incandescent Bulbs |
1.0 |
|
Halogen Bulbs |
1.0 |
|
Compact Fluorescent Lamps (CFLs) |
0.5 - 0.6 |
|
Fluorescent Tubes |
0.5 - 0.9 |
|
LED Lamps |
0.9 - 1.0 |
|
High-Pressure Sodium (HPS) |
0.9 - 1.0 |
|
Metal Halide |
0.8 - 1.0 |
|
Induction Lamps |
0.9 - 1.0 |
|
Neon Signs |
0.6 - 0.7 |
|
HID (High Intensity Discharge) |
0.8 - 0.9 |
Basic Equations:
Power Conversion
When measuring power (P) in watts, use this formula to calculate watts from voltage and current:
- Power (W) = Voltage (V) × Current (A)
To reverse the calculation and convert amps to watts, use the following formula:
- Watts = Amps × Volts
Milliamperes Conversion Formula
Milliamperes (mA) current is a measurement of electric charge or the strength of small electric currents. It's equal to 1 ampere (A) divided by 1,000. Use this formula below to convert current from Power and Voltage:
- Current (mA) = Current (A) ÷ 1000