The 555 timer is one of the most popular chips ever made, and it runs in two classic modes. In astable mode it oscillates continuously, and in monostable mode it fires a single timed pulse when triggered. This calculator handles both. For astable mode enter the two resistors Ra and Rb and the timing capacitor to get the output frequency, the period, and the duty cycle using the standard 1.44 divided by Ra plus two Rb times C relationship. For monostable mode enter one resistor and the capacitor to get the one shot pulse width, which is 1.1 times R times C. These formulas match the classic bipolar NE555, so you can design blinkers, tone generators, delays and pulse stretchers with confidence. Enter your parts, choosing convenient units, and read the timing instantly in your browser.
The 555 timer is one of the most popular chips ever made, and it runs in two classic modes. In astable mode it oscillates continuously, and in monostable mode it fires a single timed pulse when triggered.
Yes. NE555 Timer Calculator is completely free, with no sign-up and no usage limits.
Yes. NE555 Timer Calculator runs in any modern web browser. There is nothing to download or install.
Yes. NE555 Timer Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.