(the gap between the "high" and "low" switching points) of the specific chip you're using. For a 74HC14 running at , the most accurate empirical formula to use is:
So for a quick estimate: ( R ) in Ohms, ( C ) in Farads → ( f ) in Hz. 74hc14 oscillator calculator full
You don't need special software. Here's how to build a in Excel or Google Sheets: (the gap between the "high" and "low" switching
A "calculator" is useless if the values you pick fall outside the physical capabilities of the chip. 74hc14 oscillator calculator full