Buck Converter Calculator
Calculate the output voltage of a DC-DC buck (step-down) converter
Volts (V)
Percentage (%) - Must be between 0 and 100%
How to Use This Calculator
Enter Input Voltage
Enter the DC input voltage (Vin) in volts. This is the voltage supplied to the buck converter.
Enter Duty Cycle
Enter the duty cycle as a percentage (0-100%). The duty cycle is the ratio of ON time to the total switching period.
Calculate Output Voltage
Click the calculate button to get the output voltage. The calculator will also display the voltage reduction percentage.
Formula
Vout = Vin × D
Where:
- Vout = Output voltage (V)
- Vin = Input voltage (V)
- D = Duty cycle (as a decimal, 0 to 1)
Example 1:
Input voltage = 24 V, Duty cycle = 50%
Vout = 24 × 0.5 = 12 V
Example 2:
Input voltage = 12 V, Duty cycle = 33.33%
Vout = 12 × 0.3333 = 4 V
Example 3:
Input voltage = 48 V, Duty cycle = 25%
Vout = 48 × 0.25 = 12 V
About Buck Converter Calculator
The Buck Converter Calculator is a free online tool that helps you calculate the output voltage of a DC-DC buck (step-down) converter. A buck converter is a switching power supply circuit that reduces the input voltage to a lower output voltage. This calculator is essential for engineers, students, and hobbyists working on power electronics projects, battery-powered devices, and voltage regulation circuits.
When to Use This Calculator
- Power Supply Design: Design buck converters for devices that need lower voltage than available
- Battery-Powered Devices: Calculate voltage conversion for portable electronics and IoT devices
- LED Driver Circuits: Determine output voltage for LED lighting systems requiring lower voltages
- Microcontroller Power: Step down from higher voltages to 3.3V or 5V for microcontrollers
- Educational Purposes: Learn about switching power supplies and DC-DC conversion
Why Use Our Calculator?
- ✅ Instant Results: Get accurate output voltage calculations in seconds
- ✅ Easy to Use: Simple interface requiring only input voltage and duty cycle
- ✅ Accurate Formulas: Uses the standard buck converter equation
- ✅ Voltage Reduction Display: Shows the percentage of voltage reduction
- ✅ Free Tool: No registration or payment required
- ✅ Educational Value: Includes formulas and examples for learning
Common Applications
Portable Electronics: Smartphones, tablets, and laptops use buck converters to step down battery voltage (3.7V-12V) to lower voltages needed by processors, memory, and other components (1.8V, 3.3V, 5V). Multiple buck converters are often used in a single device for different voltage rails.
Automotive Electronics: Vehicles have 12V or 24V battery systems, but many electronic components need 5V or 3.3V. Buck converters efficiently step down the voltage while providing stable power for microcontrollers, sensors, and communication modules.
LED Lighting: LED strips and modules often require specific voltages (12V, 24V) that may need to be stepped down from higher supply voltages. Buck converters provide efficient, regulated power for LED systems.
Industrial Control Systems: Industrial equipment often operates at 24V or 48V, but control circuits need lower voltages. Buck converters provide efficient voltage conversion with minimal heat generation.
Tips for Accurate Results
- Enter duty cycle as a percentage (e.g., 50 for 50%, not 0.5)
- Duty cycle must be between 0% and 100%
- Lower duty cycles result in lower output voltages
- Consider efficiency losses in real-world applications (actual output may be 5-10% lower)
- This calculator assumes ideal conditions; real converters have switching losses and parasitic resistances
- For continuous conduction mode (CCM), ensure inductor current doesn't drop to zero
Frequently Asked Questions
What is a buck converter?
A buck converter (step-down converter) is a DC-DC switching power supply that reduces the input voltage to a lower output voltage. It uses an inductor, switch (usually a MOSFET), diode, and capacitor to achieve voltage step-down efficiently.
What's the difference between a buck and boost converter?
A buck converter steps down voltage (Vout < Vin), while a boost converter steps up voltage (Vout > Vin). The formulas are different: Buck uses Vout = Vin × D, while Boost uses Vout = Vin / (1 - D).
Does this calculator account for efficiency losses?
No, this calculator provides ideal output voltage. Real buck converters have efficiency losses (typically 85-95%) due to switching losses, inductor resistance, and diode forward voltage. Multiply the result by efficiency to get realistic output.
What is the relationship between duty cycle and output voltage?
Output voltage is directly proportional to duty cycle. At 50% duty cycle, output is 50% of input. At 25% duty cycle, output is 25% of input. The relationship is linear: Vout = Vin × D.
Can I use this for AC input?
No, this calculator is for DC-DC buck converters. For AC input, you would need an AC-DC converter first, then a buck converter if needed.