555 Timer Calculator – Astable Mode

This tool calculates the frequency and duty cycle of a 555 timer in astable mode. Enter your values below.

Resistor R1:
Enter the first resistor value
Ω kΩ MΩ

Resistor R2:
Enter the second resistor value
Ω kΩ MΩ

Capacitor C:
Enter the capacitor value
nF µF mF

555 Timer Calculator Online Free Tool

Use 555 Timer Calculator Online Free Tool to find frequency and duty cycle for your astable circuits. Just enter resistor and capacitor values to get instant, accurate results. 

How to Use the 555 Timer Calculator (Astable Mode): 

•  Select the correct units for your resistors (R1, R2) and capacitor (C) — like Ω, kΩ, µF etc. 
•  Enter the numeric values in the input boxes for R1, R2, and C. 
•  Click on the “🔍 Calculate” button. 
•  The tool will instantly show you the frequency (Hz) and duty cycle (%) of your astable 555 timer circuit.
•  Use the theme toggle to switch between dark mode and light mode as per your preference.