Engineering calculators

Engineering calculators with live diagrams and step-by-step working.

• Ohm's Law — Solve voltage, current, resistance and power from any two known values.
• LED Resistor Calculator — Series resistor, nearest E-series value and power for one or more LEDs.
• Resistor Colour Code — Decode 4, 5 and 6-band resistors — or find the bands for any value.
• Series Resistor Calculator — Total series resistance plus current and per-resistor voltage drops.
• Parallel Resistor Calculator — Equivalent parallel resistance with branch currents and power.
• Resistivity & Wire Resistance — Resistance of a conductor from material, length, cross-section and temperature.
• Resistor Wattage Calculator — Power dissipated in a resistor and the minimum safe power rating.
• Battery Capacity Tester — Measured mAh/Wh, state of health and C-rate from a resistor discharge test.
• Capacitors in Series — Total series capacitance, charge, energy and voltage on each capacitor.
• Capacitors in Parallel — Total parallel capacitance, charge on each capacitor and stored energy.
• Inductors in Series — Total series inductance, stored energy and reactance.
• Inductors in Parallel — Equivalent parallel inductance, branch currents and reactance.
• RLC Resonant Frequency — Resonant frequency, Q-factor, bandwidth and impedance curve of a series RLC / LC tank.
• RLC Parallel Resonance — Parallel tank resonance, Q, bandwidth and dynamic impedance including inductor ESR.
• DC Power Calculator — DC power, equivalent load resistance, energy use and running cost.
• AC Power Calculator — Real, reactive and apparent power for 1-phase or 3-phase loads, plus PF-correction capacitor.
• Buck Converter Calculator — Duty cycle, inductor, output capacitor and peak currents for a step-down converter.
• Boost Converter Calculator — Duty cycle, inductor, output capacitor and switch current for a step-up converter.
• 555 Timer — Astable — Frequency, duty cycle and high/low times of a free-running 555 oscillator.
• 555 Timer — Monostable — One-shot pulse width from R and C, or the R needed for a target delay.
• Inverting Op-Amp Gain — Gain, output voltage and clipping for an inverting amplifier.
• Non-Inverting Op-Amp Gain — Gain and output of a non-inverting amplifier, or resistors for a target gain.
• Op-Amp Voltage-to-Current Converter — Output current, load compliance and sense resistor for a V-to-I (transconductance) stage, e.g. 4–20 mA.
• PCB Trace Width Calculator — Minimum trace width for a current and temperature rise, with resistance and voltage drop.
• PCB Via Array Calculator — Current capacity, resistance and number of vias needed for a power connection.
• PCB Trace Voltage Drop — Resistance, voltage drop, % of supply and power loss along a copper trace.
• Trace Impedance & Electrical Performance — Characteristic impedance, propagation delay, L and C per length for microstrip and stripline.
• Antenna Gain Calculator — Gain in dBi/dBd of a parabolic dish or any aperture from size, frequency and efficiency.
• Antenna Beamwidth Calculator — Half-power and first-null beamwidth from dish size, or estimate beamwidth from gain.
• Antenna Aperture Efficiency — Effective aperture and aperture efficiency from measured gain and physical size.
• Attenuation & dB Calculator — dB from power or voltage ratios, and π / T resistive attenuator pad design.
• ADC Resolution Calculator — LSB size, digital code, quantisation error, ideal SNR and data rate for an N-bit ADC.
• Binary Calculator — Add, subtract, multiply, divide and modulo binary numbers with decimal and hex results.
• Number System Converter — Convert between binary, octal, decimal, hexadecimal and any base from 2 to 36.
• Logic Gate Calculator — Output, truth table and IEC symbol for AND, OR, NOT, NAND, NOR, XOR, XNOR gates.
• Two's Complement Calculator — Convert signed decimals to two's complement binary/hex and back, with every step.
• Parity Bit Calculator — Generate an even/odd parity bit or check a received word for single-bit errors.
• Hamming Code Calculator — Encode data with Hamming / SECDED parity, or decode, locate and correct an error.
• Truth Table Generator — Truth table, minterms, canonical SOP/POS and simplified form for any Boolean expression.
• Karnaugh Map Solver — Minimise 2–6 variable functions from minterms and don’t-cares, with a colour-grouped K-map.
• Gray Code Converter — Convert binary or decimal to reflected Gray code and back, with the full Gray sequence.
• Bitwise Calculator — AND, OR, XOR, NOT, NAND, NOR, XNOR on decimal, hex or binary operands.
• Bit Shift Calculator — Logical and arithmetic shifts and rotations on 8–64-bit words.
• BMI Calculator — Body-mass index with WHO category, BMI Prime and healthy weight range.
• BMR Calculator — Basal metabolic rate by Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle.
• Body Fat Calculator — Body-fat percentage by the U.S. Navy tape method, with fat and lean mass.
• Calorie Calculator — Daily calorie needs (TDEE) for maintenance, weight loss or gain, with macro split.
• Pregnancy Due Date Calculator — Estimated due date, conception date, current week and trimester milestones.
• EV vs Petrol Savings Calculator — Running cost, savings, payback and CO₂ of an electric vehicle versus a petrol/diesel car.
• CO₂ Emission Calculator — Annual CO₂ footprint from driving, electricity, cooking gas and flights, with tree offset.
• Image Studio — Convert to JPG, PNG, WebP, AVIF, BMP, TIFF or PDF; crop, rotate, resize, compress to a target size and download as ZIP — files never leave your device.
• Storage Unit Calculator — Convert digital storage sizes between bits, bytes, KB, MB, GB and TB.
• Data Transfer Time — Estimate how long a file takes to transfer at a given network speed.
• UART Baud Rate — Find the closest achievable baud rate and its error for a given clock.
• SPI Clock — Compute the SPI bus clock from the system clock and a clock divider.
• I²C Pull-Up Resistor — Find the valid pull-up resistor range for an I²C bus.
• PWM Duty Cycle — Compute the on-time, off-time and period for a PWM signal.
• CAN Bit Rate — Find the CAN controller prescaler for a target bit rate and its actual error.
• Gear Ratio — Compute a gear ratio from tooth counts, and the resulting output speed.
• Torque / Power / RPM — Compute engine or motor power from torque and rotational speed.
• Fuel Economy — Convert between L/100km, km/L and miles-per-gallon (US).
• Electrical Power — Compute power dissipated by a resistance from an applied voltage.
• Voltage Drop — Estimate the voltage lost over a length of wire carrying current.
• Three-Phase Power — Compute real power delivered by a balanced three-phase supply.
• Electrical Energy — Convert power and time into total energy consumed.
• Voltage Divider — Find the output voltage of a two-resistor voltage divider.
• RC Time Constant — Compute the time constant and cutoff frequency of an RC circuit.
• Capacitor Reactance — Compute a capacitor's impedance (reactance) at a given frequency.
• Force — Compute force from mass and acceleration (Newton's second law).
• Torque — Compute torque from an applied force and lever arm radius.
• Mechanical Power — Compute rotational power from torque and rotational speed.
• Stress — Compute normal stress from an applied force and cross-sectional area.
• Strain — Compute engineering strain from an original length and its change.
• Area — Compute the area of a rectangle, circle or triangle.
• Volume — Compute the volume of a cube, box, cylinder or sphere.
• Concrete Volume — Compute the concrete volume needed for a rectangular slab or footing.
• Unit Converter — Convert a value between common length, mass, temperature, speed, volume and storage units.
• Percentage — Find what percent one value is of another, a percentage of a value, or a percent change.
• Scientific Calculator — Evaluate an expression with trig, log, powers and roots.
• Trigonometry (Right Triangle) — Solve a right triangle's sides from one angle and the hypotenuse.