555 Timer Calculator
Calculate astable frequency, period, and duty cycle, or monostable pulse width from resistor and capacitor values.
Select astable or monostable mode and enter resistor and capacitor values with units.
555 timer basics
The NE555 is a versatile timer IC. In astable mode it oscillates continuously: frequency depends on R1, R2, and C. In monostable mode it produces a single timed pulse when triggered. These formulas assume ideal components and the standard bipolar 555; actual timing may vary slightly with supply voltage and temperature.
