| 555 Timer Calculator

The formulas to calculate the time high and time low for the timer are as follows (typically):

Time HIGH (seconds) Time LOW (seconds)
$$x = {0.693(R_1 + R_2) * C_1}$$ $$x = {0.693(R_2 * C_1)}$$

You can use the calculator below to calculate these values as well as frequency and duty cycle.

- Value of R1
- Value of R2
- Value of C1


Frequency 0.000 Hz
Duty Cycle 0.000 %
Time HIGH 0.000 s
Time LOW 0.000 s


Blinking LED schematic

Interactive Simulation: