PWM Duty Cycle Voltage Calculator
Calculate PWM average voltage, RMS voltage, duty cycle from target voltage, PWM code value and RC filter ripple for Arduino, ESP32, STM32 and electronics projects.
⚡ Maker Rule: PWM is not true analog voltage by itself. The average voltage is based on duty cycle, but a load or RC filter decides how smooth it becomes. Use this with the ADC Resolution Calculator, RC Debounce Calculator, MOSFET Gate Resistor Calculator and LED Resistor Calculator.
▥ PWM Duty Cycle — Digital Pulses to Average Voltage
PWM High Voltage
PWM Low Voltage
Duty Cycle
PWM Resolution
PWM Frequency Optional
Load Type
Average voltage = Vlow + duty × (Vhigh − Vlow). RMS voltage is useful for resistive heating power.
Presets:Arduino 5VESP32 3.3V12V motor PWM
PWM High Voltage
PWM Low Voltage
Target Average Voltage
PWM Resolution
This finds duty cycle and PWM register/code value needed for a target average voltage.
PWM High Voltage
Duty Cycle
PWM Frequency
Filter Resistor
Filter Capacitor
Target Ripple Optional
This is a simplified first-order RC estimate. Real ripple depends on load impedance and PWM waveform.
📐 Formula Reference
Average Voltage
Vavg = Vlow + D × (Vhigh − Vlow)
RMS Voltage
Vrms = √(D × Vhigh² + (1 − D) × Vlow²)
Duty from Target
D = (Vtarget − Vlow) ÷ (Vhigh − Vlow)
RC Cutoff
fc = 1 ÷ (2πRC)
📋 Quick Reference
Common PWM
Arduino analogWrite8-bit
ESP32 PWMflexible
Servo PWMpulse width
Use Average For
Filtered analogVavg
LED dimmingbrightness
Motor speedapprox
Use RMS For
Heater powerVrms
Resistive loadpower
Power estimateI²R
📚 Engineering Notes
PWM average is not automatically smooth DCA PWM pin switches between high and low. A filter or slow load creates an average effect.
Duty controls average voltageWith 5V high and 0V low, 60% duty gives about 3V average.
RC filter reduces rippleHigher PWM frequency, larger resistor/capacitor, and lighter load generally reduce ripple.
For power switching, check MOSFET lossUse the MOSFET Power Loss Calculator and MOSFET Gate Resistor Calculator.
What is a PWM Duty Cycle Voltage Calculator?
A PWM duty cycle voltage calculator estimates the average voltage, RMS voltage and required duty cycle for a PWM signal. It is useful for Arduino, ESP32 and microcontroller PWM outputs.
How PWM average voltage is calculated
The average voltage is calculated by multiplying duty cycle by the difference between high and low voltage, then adding the low voltage. For a 5V PWM signal at 50% duty, the average voltage is about 2.5V.
PWM average voltage vs RMS voltage
Average voltage is useful for filtered analog signals and slow loads. RMS voltage is more useful for resistive power calculations such as heaters.
Important limitation
This calculator gives ideal PWM math and simple RC estimates. Real circuits depend on load impedance, MOSFET switching, PWM frequency, capacitor ESR, op-amp buffering, ADC sampling and power supply noise.
❓ Frequently Asked Questions
No. PWM switches between high and low states. The average can behave like analog voltage only after filtering or with a slow load.
For 0V low and 5V high, 50% duty gives 2.5V average.
Yes, PWM is commonly used for DC motor control, but you need a proper MOSFET/driver and flyback protection for inductive loads.