Electronics Calculators

Solve for voltage, current, or resistance. Power dissipation included.

Decode 4-band resistor color codes or enter a value to see the corresponding bands.

Calculate output voltage, ratio, and current for resistor voltage divider circuits.

Calculate the current-limiting resistor for any LED. Nearest E24 standard value included.

Calculate frequency, duty cycle and pulse width for 555 astable and monostable circuits.

Visualize magnitude and phase response with an interactive Bode plot. Low-pass and high-pass modes.

Calculate total resistance for series and parallel combinations. Supports up to 6 resistors.

Calculate minimum PCB trace width for any current using IPC-2221. Supports external/internal layers, 1oz/2oz copper, temperature rise. Trace resistance and voltage drop included.

Look up wire diameter, resistance, and current capacity for any AWG. Voltage drop calculator for copper and aluminum wire.

Calculate RC time constant and the time a capacitor takes to charge to any voltage. Charging curve included.

Estimate battery runtime from capacity, current draw, efficiency, and self-discharge. Continuous and duty cycle modes.

Calculate resistor power dissipation (P = V²/R, I²R, V×I). Get recommended wattage rating with ×2 safety factor and thermal derating curve.

Decode ceramic capacitor 3-digit codes (104 = 100nF, 103 = 10nF). Convert between code and pF/nF/µF. Tolerance letter decoder included.

Convert between decibels and voltage/power ratios in both directions. Common presets included.

Calculate inverting and non-inverting op-amp gain in V/V and dB. Includes output voltage and circuit diagram.

Calculate output voltage and resistor values for LM317 adjustable voltage regulator circuits.

Calculate maximum heat sink thermal resistance (Rth_sa) and junction temperature. Enter power, Rth_jc from datasheet, and ambient temperature.

Calculate period, tON, tOFF, and average voltage for PWM signals. Inverse mode: find duty cycle from target voltage.

Calculate total resistance for up to 5 parallel resistors. Branch currents from optional supply voltage.

Calculate total resistance for up to 5 series resistors. Voltage drop across each from optional supply voltage.

Calculate electrical power (V×I, V²/R, I²R), energy in kWh, and electricity cost estimation.

Calculate voltage drop across cables for copper and aluminum conductors. Supports mm² and AWG wire sizes with IEC limits.

Calculate series resistor, zener current, and power dissipation for zener voltage regulator circuits.

Calculate Q-point, load line, and operating region for BJT common emitter voltage divider bias circuits.

Calculate resonant frequency, angular frequency and characteristic impedance for LC circuits.

Calculate resonant frequency, Q factor, bandwidth, and cutoff frequencies for RLC series circuits. Impedance curve included.

Calculate power dissipation, heatsink needs, and capacitor values for 7805/7812/78xx regulators.

Calculate transformer turns ratio, secondary voltage, current, and power from primary winding parameters.

Calculate op-amp −3dB bandwidth from gain-bandwidth product. Supports LM741, NE5532, TL071 and custom GBW. Bode plot and margin check included.

Calculate valid pull-up resistor range for I2C buses. Accounts for supply voltage, bus speed, and capacitance.

Calculate gate resistor, drive power, and switching times for N-channel MOSFET circuits.

Convert between frequency and period. Hz, kHz, MHz, GHz, RPM, and rad/s with reference table.

Calculate NTC thermistor resistance from temperature or temperature from resistance. ADC voltage divider included.

Calculate discharge time constant, voltage decay, and time to reach any target voltage.

Calculate bridge balance resistor and output voltage for Wheatstone bridge sensor circuits.

Calculate energy stored (E = ½CV²) and charge (Q = CV) for any capacitor. Inverse mode: find C for target energy.

Calculate inductor impedance, stored energy, Q factor, and self-resonant frequency.

Calculate capacitive reactance (Xc), total impedance with ESR, and view reactance vs frequency curve. Bypass capacitor guide.

Calculate duty cycle, minimum inductor, and output capacitor for Buck, Boost, and Buck-Boost DC-DC converters.

Calculate resistors, power, and current for LED arrays in series, parallel, and series-parallel matrix configurations.

Calculate dipole, monopole, and 5/8 wave antenna lengths for any frequency. Results in meters, cm, inches, and feet.

Design Pi and T resistive attenuator pads. Enter attenuation in dB and impedance. Nearest E24 standard values and circuit diagrams included.

Voltage divider with load resistance. Shows Vout error due to loading effect and when a buffer op-amp is needed.

Calculate upper and lower threshold voltages and hysteresis for inverting and non-inverting Schmitt trigger op-amp circuits.

Determine output state (HIGH/LOW) and voltage for push-pull and open-collector comparator configurations.

Calculate output current and sense resistor power for Howland current pump V-to-I converter circuits.

Calculate 555 astable frequency and duty cycle with a diode across Rb. Achieve duty cycles below 50%.

Calculate C1 and C2 load capacitors for Pierce oscillator circuits from crystal CL and stray capacitance.

Convert dBm, dBu, dBV, and dBW to absolute power and voltage. Audio level reference table included.

Calculate thermal noise voltage, spectral density (nV/√Hz), and noise power for any resistor value and bandwidth.

Calculate skin depth in copper, aluminum, and silver at any frequency. Reference table from 50 Hz to 1 GHz.