Is this calculation free and private?

Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.

What do I need to enter?

Just Resistor Ra, Resistor Rb and Timing Capacitor C. Every field has a sensible default you can start from.

Is my data uploaded anywhere?

No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.

Does it work on a phone?

Yes. The layout adapts to small screens and needs no app or signup.

555 Timer Astable Frequency & Duty Cycle Calculator

Calculate oscillation frequency (Hz), high/low period times (t1/t2), and duty cycle percentage for NE555 astable multivibrators.

100% free
Private in browser
No signup
No watermarks

Resistor Ra (Ohms Ω, Pin 7 to Vcc)

Resistor Rb (Ohms Ω, Pin 7 to Pin 2/6)

Timing Capacitor C (Microfarads µF)

Oscillation Frequency (Hz)

138.8

Duty Cycle High (%)

54.8

Total Clock Period T (ms)

7.21

Output High Time t1 (ms)

3.95

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About 555 Timer Astable Frequency & Duty Cycle Calculator

Calculate oscillation frequency (Hz), high/low period times (t1/t2), and duty cycle percentage for NE555 astable multivibrators. Enter Resistor Ra, Resistor Rb and Timing Capacitor C and the tool works out Oscillation Frequency, Duty Cycle High and Total Clock Period T straight away. Everything runs in your browser, so your data never leaves your device.

How to use 555 Timer Astable Frequency & Duty Cycle Calculator

Enter Resistor Ra, Resistor Rb and Timing Capacitor C.
Change any value to see the result update instantly.
Read Oscillation Frequency, Duty Cycle High and Total Clock Period T in the results panel — copy or download what you need.

Key features

Shows Oscillation Frequency (Hz)
Shows Duty Cycle High (%)
Shows Total Clock Period T (ms)
3 adjustable inputs, results update as you type
No signup, no limits

Frequently asked questions

Is this calculation free and private?: Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
What does the 555 Timer Astable Frequency & Duty Cycle Calculator give me?: It works out Oscillation Frequency, Duty Cycle High, Total Clock Period T and Output High Time t1, updating live as you change the inputs.
What do I need to enter?: Just Resistor Ra, Resistor Rb and Timing Capacitor C. Every field has a sensible default you can start from.
Is my data uploaded anywhere?: No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
Does it work on a phone?: Yes. The layout adapts to small screens and needs no app or signup.

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