Electrical calculators
Circuit Calculators
15 tools
Ohm's law, Kirchhoff, dividers, RC/RLC, and passive networks.
Popular in Circuits
Featured tools from the Family registry.
- Ohm's Law Calculator Enter any two of voltage, current, resistance, and power to solve the remaining values. Runs locally in your browser. Free online tool — no sign-up.
- Voltage Divider Calculator Solve a two-resistor voltage divider: enter exactly three of Vin, R1, R2, and Vout to find the fourth. Also reports current, power, ratio, and Rth. Try it free.
- Kirchhoff's Law Calculator Apply Kirchhoff’s voltage law to a series loop or current law to a parallel node with N resistors.
- RC Time Constant Calculator Calculate the RC time constant τ = R×C, solve for R or C, and get −3 dB frequency plus 2.2τ / 5τ timing estimates. Runs locally in your browser.
All Circuits
Every live calculator in this family. URLs stay /calc/electric/…
- 555 Timer Calculator Astable frequency, period, high/low times and duty — or monostable pulse width — for the classic 555 timer from R and C. ln(2)-canonical NE555 timing with device-applicability warnings.
- Capacitance Calculator Compute parallel-plate capacitance C=εA/d or combine series/parallel capacitors. Runs locally in your browser.
- Current Divider Calculator Split a total current between two parallel resistors: I1 = It·R2/(R1+R2), I2 = It·R1/(R1+R2). Runs locally in your browser.
- High-Pass Filter Calculator First-order RC high-pass cutoff fc=1/(2πRC) and optional |H(f)|. Twin of the LPF calculator.
- Kirchhoff's Law Calculator Apply Kirchhoff’s voltage law to a series loop or current law to a parallel node with N resistors.
- LED Resistor Calculator Size the series resistor for one or more LEDs: R = (Vs − n·Vf) / If.
- Low-Pass Filter Calculator Design a first-order RC low-pass filter: solve any two of R, C, and cutoff fc = 1/(2πRC), and evaluate magnitude |H(f)| in linear and dB. Runs locally in your browser.
- Ohm's Law Calculator Enter any two of voltage, current, resistance, and power to solve the remaining values. Runs locally in your browser. Free online tool — no sign-up.
- Parallel Resistor Calculator Compute equivalent resistance of two or more resistors in parallel. Runs locally in your browser.
- RC Time Constant Calculator Calculate the RC time constant τ = R×C, solve for R or C, and get −3 dB frequency plus 2.2τ / 5τ timing estimates. Runs locally in your browser.
- Resistor Color Code Calculator IEC 60062 band colors → Ω ±tol. Runs locally in your browser.
- RLC Resonance Calculator Calculate RLC resonant frequency f₀, Q factor, bandwidth, and reactance at resonance for series or parallel circuits from L, C, and R. Runs locally in your browser.
- Series Capacitor Calculator Combine capacitors in series: 1/C = Σ 1/Ci. Runs locally in your browser.
- Voltage Divider Calculator Solve a two-resistor voltage divider: enter exactly three of Vin, R1, R2, and Vout to find the fourth. Also reports current, power, ratio, and Rth. Try it free.
- Wheatstone Bridge Calculator Compute Wheatstone bridge output voltage and balance from Vin and four resistors. Runs locally in your browser.