Electronics Calculators & Tools
Free, fast electronics calculators. Use them here or embed them on your own site.
Resistor Color Code Calculator
Pick the color bands to instantly get the resistance (Ω) and tolerance. Supports 4, 5 and 6-band resistors.
Ohm's Law Calculator
Enter any two of voltage (V), current (I), resistance (R) or power (P); the other two are calculated automatically.
LED Resistor Calculator
Enter supply voltage, LED forward voltage and current to get the series resistor and the nearest standard value.
Capacitor Code Calculator
Enter the 3-digit code on a ceramic capacitor (e.g. 104) to see the capacitance in pF, nF and µF.
SMD Resistor Code Calculator
Enter the code on an SMD resistor (472, 4702, 4R7 or EIA-96 01C) to instantly get the resistance.
PCB Trace Width Calculator
Calculate the required PCB trace width from current, temperature rise and copper weight per IPC-2221.
555 Timer Calculator
Calculate frequency, period, duty cycle and pulse width from R and C for an NE555 astable/monostable circuit.
LM317 Voltage Calculator
Calculate the output voltage of an LM317 adjustable regulator from R1 and R2 (or the R2 needed for a target voltage).
Voltage Divider Calculator
Instantly compute the output voltage (Vout), current and dissipated power of a two-resistor voltage divider.
Standard Resistor Value Finder
Find the nearest standard E12/E24/E96 resistor value to your calculated value, with the percentage deviation.
Parallel & Series Resistor Calculator
Compute the series and parallel equivalent of several resistors at once — just enter the values separated by commas.
Parallel & Series Capacitor Calculator
Compute the parallel and series equivalent capacitance of several capacitors at once (in µF).
NTC Thermistor Calculator (Beta)
Compute an NTC thermistor's resistance at a temperature, or the temperature from a measured resistance, using the Beta model.
RC Filter Calculator (Cutoff Frequency)
Instantly compute the −3 dB cutoff frequency (fc) and time constant of an RC filter from one resistor and one capacitor.
LC Resonant Frequency Calculator
Compute the resonant frequency and characteristic impedance of an LC circuit from an inductor and a capacitor.
Op-Amp Gain Calculator
Compute the voltage gain (V/V and dB) of inverting and non-inverting op-amp amplifiers from the resistor values.
Zener Diode Calculator (Series Resistor)
Compute the series resistor a zener regulator needs, plus the power dissipated in the resistor and the zener.
LED Array Calculator (Series/Parallel)
Compute the resistor each string needs and the total current when arranging multiple LEDs in series and parallel.
Antenna Length & Wavelength Calculator
Compute the wavelength and the physical length of a dipole / monopole / loop antenna from frequency, with velocity factor.
PCB Trace Impedance Calculator (Microstrip/Stripline)
Compute a PCB trace's characteristic impedance (Z₀), effective dielectric and propagation delay for microstrip or stripline.