Volts to mA Calculator

Convert electrical voltage to current using Ohm's Law. Calculate milliamps from volts and resistance or power for accurate circuit analysis.

Electrical Calculator:

Convert between electrical voltage and current measurements for circuit design, troubleshooting, and electrical engineering applications.

Electrical Current Converter

Conversion Direction

Enter voltage in volts or current in milliamps

Choose how to calculate current from voltage

Electrical resistance in ohms

Current Results

Enter values and click "Convert"

to calculate current

Voltage and Current Conversion

Voltage and current are fundamental electrical quantities, but they measure different aspects of electricity. Voltage represents electrical potential difference, while current represents the flow of electrical charge. Converting between volts and milliamps requires additional information about the circuit because current depends on both voltage and circuit characteristics.

This calculator uses Ohm's Law and power relationships to accurately convert between voltage and current measurements. The key insight is that current cannot be determined from voltage alone - you need either resistance or power consumption data.

Why Resistance or Power Is Required

According to Ohm's Law (V = I × R), the relationship between voltage, current, and resistance is direct. Similarly, power relationships (P = V × I) connect voltage, current, and power consumption.

  • Ohm's Law: Voltage = Current × Resistance
  • Power Law: Power = Voltage × Current
  • Circuit characteristics determine current flow
  • Safety consideration: Proper calculations prevent electrical hazards

Electrical Conversion Formulas

The calculator implements standard electrical engineering formulas:

Using Resistance (Ohm's Law):
Current (mA) = (Voltage ÷ Resistance) × 1000
I = V/R, then converted to milliamps
Using Power:
Current (mA) = (Power ÷ Voltage) × 1000
I = P/V, then converted to milliamps
Reverse Calculations:
Voltage = Current × Resistance
Power = Voltage × Current

All calculations automatically handle unit conversions to ensure accuracy.

Practical Electrical Examples

Here are common voltage-to-current calculations used in electronics:

Voltage (V) Resistance (Ω) Power (W) Current (mA) Application
5 250 - 20 LED circuit
12 600 - 20 Arduino project
9 - 0.18 20 Battery-powered device
24 - 0.48 20 Industrial sensor
3.3 165 - 20 Microcontroller circuit
1.5 75 - 20 Watch battery circuit
48 - 2.4 50 DC motor controller
0.5 25 - 20 Precision measurement
6 300 - 20 Solar panel circuit
15 - 0.3 20 USB device charging
2.4 120 - 20 Bluetooth module
7.4 - 0.148 20 Lithium battery circuit
18 900 - 20 Stepper motor driver
4.5 - 0.09 20 Wireless sensor node
1.8 90 - 20 NFC reader circuit
28 - 0.56 20 High-voltage relay
0.9 45 - 20 Temperature sensor
36 1800 - 20 HVAC control panel
11 - 0.22 20 Security camera system
2.7 135 - 20 GPS tracking device
8.1 - 0.162 20 Medical infusion pump
22 1100 - 20 Industrial PLC system
13.5 - 0.27 20 Audio amplifier circuit
3.6 180 - 20 Smart home controller
0.25 12.5 - 20 Coin cell battery circuit
30 - 0.6 20 Automotive electronics
Safety Warning:

Electrical calculations should only be used for design and analysis purposes. Always verify measurements with proper test equipment and follow electrical safety standards in your region.