Engineering tools
Free calculators for everyday electronics work.
Component Calculators
Resistor Color Code Calculator
Decode 4, 5 and 6-band resistors with a live color preview.
Open →SMD Resistor Code Calculator
3-digit, 4-digit and EIA-96 marking decoder with package preview.
Open →E-Series Standard Value Finder
Nearest E12/E24/E48/E96 value with error and neighbors.
Open →SMD Capacitor Value Finder
Snap any target to the nearest standard MLCC value (E3/E6/E12/E24) with its 3-digit code, neighbors and error.
Open →Coil Inductance Calculator
Single-layer air-core solenoid inductance from turns and geometry (Wheeler), or turns for a target inductance.
Open →Analog & Filters
Ohm's Law Calculator
Enter any two of voltage, current, resistance and power to get the other two.
Open →Voltage Divider Calculator
Solve Vin, Vout, R1 or R2 of a resistive divider.
Open →Series & Parallel RLC Calculator
Equivalent value of series/parallel resistor, inductor or capacitor networks.
Open →Reactance Calculator
Capacitive Xc and inductive XL at any frequency.
Open →RC Charging / Discharging Calculator
Time constant, voltage curve and time to reach a target voltage.
Open →RC Filter Calculator
Cutoff frequency, time constant and Bode plot for RC low-pass / high-pass filters.
Open →RL Filter Calculator
Cutoff frequency, time constant and Bode plot for RL low-pass / high-pass filters.
Open →RLC Filter Calculator
Resonance, Q, damping and Bode plot for series RLC low-pass, high-pass, band-pass and band-stop filters.
Open →Active Filter Designer (Sallen-Key / MFB)
f₀ and Q to real R/C values rounded to the E-series, with the resulting error and schematic.
Open →Op-Amp Gain Calculator
Inverting (−Rf/Rin) and non-inverting (1+Rf/Rg) gain with dB and output voltage — schematic per config.
Open →Signals & DSP
Chirp Signal Spectrogram
Linear, exponential and quadratic sweeps with a live STFT spectrogram.
Open →FFT Spectrum Analyzer
Multi-tone signal + noise through a windowed FFT — live magnitude spectrum.
Open →Window Function Comparator
Hann, Hamming, Blackman, flat-top: shapes, lobes, sidelobes and ENBW overlaid.
Open →Biquad Filter Designer
RBJ cookbook IIR coefficients (LPF/HPF/BPF/notch/peak/shelf) with response plot.
Open →FIR & IIR Filter Designer
Windowed-sinc FIR and Butterworth/Cheby I-II/Elliptic/Bessel IIR — coefficients, response, pole-zero map, float/Q15 C code.
Open →dB / dBm Converter
Ratio ↔ dB (10·log vs 20·log) and dBm ↔ watts ↔ volts at any impedance.
Open →Goertzel Calculator
Single-bin tone detection: bin, coefficient, bandwidth and C code. DTMF preset.
Open →Allpass / Phase Corrector Designer
Phase-correction sections with phase + group delay plots — magnitude stays flat.
Open →THD / SINAD / ENOB Calculator
Harmonics + noise in, every ADC datasheet metric out.
Open →Phase Noise → Jitter Converter
Integrate a dBc/Hz profile into RMS phase error and femtosecond jitter.
Open →Power
Three-Phase Power Calculator
Phase voltage/current, apparent, real and reactive power for delta and wye systems.
Open →Battery Life Calculator
Estimated runtime from capacity, average load current and a real-world derating factor.
Open →Wire Ampacity Calculator (AWG)
Max current for AWG gauges (chassis / power transmission) with diameter, area, resistance and voltage drop.
Open →Voltage Drop Calculator
Conductor voltage drop from current, gauge, length and material — with percent of supply and power loss.
Open →LED Series Resistor Calculator
Series resistor from supply, LED Vf and current — nearest E-series value and power.
Open →Buck / Boost Converter Calculator
Duty cycle, inductor ripple current and output voltage ripple for a switching converter.
Open →Heat Sink & Junction Temp Calculator
Junction temperature from the θJC + θCS + θSA chain — or the heat sink θSA you need.
Open →mAh ↔ Wh Battery Capacity Calculator
Convert mAh ↔ Wh ↔ kWh with voltage and size series/parallel packs (pack voltage, capacity, energy).
Open →PCB & High-Speed
PCB Trace Width Calculator (IPC-2221)
Required copper width from current, temperature rise, copper weight and layer — with cross-section and resistance.
Open →PCB Impedance Calculator (Microstrip / Stripline / Differential)
Single-ended Z₀ and differential pair impedance for microstrip and stripline, with cross-section, εeff and propagation delay.
Open →PCB Via Calculator
Plated barrel copper area, via resistance, current capacity (IPC-2221) and parasitic inductance from drill, plating and board thickness.
Open →Trace Delay & Length Matching
Propagation delay (ps/mm), signal velocity, max length mismatch for a skew budget, and the critical length where a trace becomes a transmission line.
Open →Embedded Copper Resistor / Heater
Sheet resistance from copper weight, squares from a trace's length and width, resistance at 20 °C and at temperature, plus heater mode (power, current, self-heating ΔT).
Open →PDN / Decoupling Target Impedance
Target impedance from supply, ripple and transient current, number of decaps at a target frequency from their mounting inductance, plus capacitor SRF.
Open →PCB Trace Resistance & IR Drop
DC resistance of a copper trace (temperature-corrected), the voltage drop and power loss at a given current, with cross-section and current density.
Open →Thermal Via Array (θ)
Thermal resistance of a plated via (copper barrel plus fill) and of N vias in parallel, from drill, plating, board thickness and fill — for sinking heat to a plane.
Open →Skin Depth & AC Resistance
Skin depth vs frequency for copper, silver, gold and aluminium, the skin-effect onset frequency, and DC vs AC resistance for a round wire or PCB trace.
Open →RF & Wireless
LC Resonant Frequency Calculator
Solve f, L or C for an LC tank from f0 = 1/(2π√LC), plus characteristic impedance Z0 = √(L/C).
Open →Antenna Length & Wavelength Calculator
Wavelength from frequency, plus half-wave dipole and quarter-wave whip lengths with velocity factor.
Open →Pi & T Attenuator Calculator
Pi-pad and T-pad attenuator resistor values from attenuation (dB) and impedance — equal or unequal Zin/Zout, with schematic and minimum-loss limit.
Open →Control Systems
PID Tuning Simulator
FOPDT/SOPDT/integrating plants, five tuning methods compared live, relay autotune, manual bump test, anti-windup C code.
Open →Second-Order Step Response
Percent overshoot, peak time, rise time, 2% and 5% settling time, damped frequency and decay rate from the damping ratio and natural frequency, with a live step-response plot.
Open →First-Order Step Response
The 63/86/95/98/99% time-constant milestones, 10–90% rise time, 2% and 5% settling time, bandwidth and pole, plus the time to reach any target percentage.
Open →Damping ↔ Overshoot ↔ Phase Margin
Convert between damping ratio, percent overshoot, quality factor Q and phase margin for a second-order loop, plus the resonant peak.
Open →Steady-State Error & System Type
Static position, velocity and acceleration error constants and the steady-state error to a step, ramp and parabola input from the system type and gain.
Open →PID Discretization → C Code
Continuous Kp/Ki/Kd and a sample time into discrete velocity-form coefficients (q0,q1,q2) for backward Euler, Tustin or forward Euler, with ready C code and anti-windup.
Open →Lead / Lag Compensator Designer
Pole/zero ratio α, time constant, zero and pole frequencies and the gain at the center frequency from a target maximum phase and the frequency where it occurs.
Open →Routh-Hurwitz Stability
Enter the characteristic-polynomial coefficients to get the full Routh array, the number of right-half-plane (unstable) roots and a stable / unstable verdict.
Open →PWM & Timing
PWM Frequency & Resolution
PWM frequency, duty resolution in bits and timer registers (ARR/PSC/CCR) from the timer clock.
Open →PWM → Voltage (RC DAC)
Average voltage, ripple, cutoff and effective resolution of a PWM filtered by an RC low-pass — live waveform.
Open →555 Timer Calculator
Astable frequency, duty and high/low times from R1, R2, C, or monostable pulse width from R, C.
Open →Frequency ↔ Period ↔ RPM
Convert between Hz/kHz/MHz, period (s/ms/µs/ns), RPM and angular velocity — edit any field.
Open →Temperature & Sensors
Thermocouple Calculator
All types (B, E, J, K, N, R, S, T): °C ↔ µV with cold-junction compensation, per NIST ITS-90.
Open →NTC Thermistor Calculator
Beta-model resistance ↔ temperature conversion.
Open →PT100 / PT1000 Calculator
RTD resistance ↔ temperature via Callendar–Van Dusen (IEC 60751).
Open →4–20 mA Scaling Calculator
Loop current ↔ process value with percent of span and NAMUR fault limits.
Open →Embedded & MCU
UART Baud Rate Calculator
Divider, actual baud and error % for any clock — with a common-baud table.
Open →ADC Resolution Calculator
LSB size, counts, ideal SNR and code ↔ voltage conversion.
Open →Timer Prescaler Calculator
Update frequency from PSC/ARR — or the best register pair for a target frequency.
Open →Q-Format Converter
Float ↔ Q7/Q15/Q31 with hex, quantization error and the fixed-point arithmetic rules.
Open →ASCII / Text Converter
Text ↔ hex/dec/bin/oct byte codes with C array output and a live per-character breakdown.
Open →Number / Base Converter
Hex/dec/bin/oct with 8–64-bit width, two's complement, a clickable bit editor and bitwise ops.
Open →Crystal PPM Calculator
Convert crystal ppm tolerance to frequency deviation (Hz), the min/max range and clock drift per day and year.
Open →CAN Bit Timing Calculator
BRP, TSEG1, TSEG2 and sample point for a target CAN bitrate, with actual bitrate, error and STM32 bxCAN register values.
Open →I²C Pull-up Resistor Calculator
Minimum and maximum pull-up from Vcc, bus capacitance and speed mode (rise time + sink current), with a recommended E12 value.
Open →CRC Calculator
CRC-8 / CRC-16 (CCITT, XMODEM, Modbus) / CRC-32 from text or hex with selectable polynomial, reflection and xor-out, plus bitwise C code.
Open →Quadrature Encoder Calculator
Counts per revolution for x1/x2/x4 decoding, angular resolution, count frequency, counts per sample period, gear ratio and linear speed.
Open →Watchdog Timeout Calculator
Timeout from watchdog clock, prescaler and reload — or the prescaler and reload for a target timeout, with STM32 IWDG register values.
Open →Register Bitfield Builder
Compose an MCU register from named bit fields or decode a value back, with a clickable bit map in hex, binary and decimal.
Open →DDS / NCO Calculator
Output frequency from the phase-accumulator tuning word and clock, frequency resolution, the tuning word for a target frequency, phase step per clock and phase-truncation SFDR.
Open →CIC Filter Calculator
DC gain and register bit growth, passband droop at the band edge and worst-case alias / image rejection for a cascaded integrator-comb decimation or interpolation filter.
Open →