Free tools for engineering & physics calculations and conversions. All tools run in your browser with no data sent to any server.
All Engineering & Physics Tools
Ohm's Law Calculator
Compute voltage, current, or resistance
Resistor Color Code Calculator
Decode 4, 5, and 6 band resistor color codes to find resistance values
Power Law Calculator
Compute electrical power from voltage and current
Power Factor Calculator
Calculate power factor, phase angle, reactive power, and estimated current
Force Calculator
Calculate force from mass and acceleration
Kinetic Energy Calculator
Calculate kinetic energy, mass, or velocity with unit conversions
Potential Energy Calculator
Calculate gravitational potential energy, mass, or height with unit and gravity presets
FOV Visualizer
Visualize and calculate field of view angles for cameras, games, and VR
Sun Angle & Shadow Calculator
Calculate solar altitude, azimuth, and shadow length for any location and time
Battery Runtime Calculator
Estimate battery life based on capacity, load, and safety factor
Voltage Divider Calculator
Calculate unloaded and loaded output voltage, divider current, and resistor power dissipation
Density Calculator
Calculate density, mass, or volume with common material presets
Half-Life Calculator
Calculate radioactive decay, remaining quantity, and elapsed half-lives
Projectile Motion Calculator
Calculate range, max height, and flight time of projectile motion
Ideal Gas Law Calculator
Solve PV = nRT for any variable with unit conversions
LED Resistor Calculator
Calculate the correct current-limiting resistor for LEDs with color code display
Moment of Inertia Calculator
Calculate moment of inertia for common shapes with parallel axis theorem
3D Print Time Estimator
Estimate 3D printing time based on model volume, layer height, print speed, and infill percentage
Wavelength Calculator
Convert between wavelength, frequency, and energy for electromagnetic waves with spectrum visualization
Stair Calculator
Calculate rise, run, number of steps, and code compliance for stairs
Torque Calculator
Calculate torque from force and lever arm distance with unit conversion
Spring Calculator
Calculate spring force, displacement, and energy using Hooke's Law
Pulley Calculator
Calculate mechanical advantage, belt length, and speed ratios for pulley systems
BTU Calculator
Calculate heating and cooling BTU requirements for any room
Pendulum Calculator
Calculate period, frequency, and length of a simple pendulum
Impedance Calculator
Calculate AC circuit impedance, reactance, and phase angle for RLC circuits
555 Timer Calculator
Calculate 555 timer IC frequency, duty cycle, and component values
Solar Panel Calculator
Estimate solar panel system size, costs, savings, and payback period for your home
HVAC BTU Calculator
Calculate heating and cooling BTU requirements for any room size
Pipe Flow Calculator
Calculate flow rate, velocity, and pressure drop in pipes
Air Conditioner Size Calculator
Calculate the right AC size in BTU for your room based on dimensions and conditions
Brick Calculator
Calculate how many bricks you need for a wall, patio, or project with mortar allowance
Staircase Calculator
Calculate stair dimensions — rise, run, number of steps, and stringer length
Battery Life Calculator
Calculate battery runtime from capacity and load, or required capacity for desired runtime
Air Density Calculator
Calculate air density from temperature, pressure, and humidity using the ideal gas law
Wire Size Calculator
Calculate the right wire gauge (AWG) for your electrical project based on current, distance, and voltage drop
Capacitor Charge Calculator
Calculate RC circuit charge/discharge time, time constant, and voltage curves
Snow Load Calculator
Calculate snow load on roofs and structures based on depth, density, and area
Voltage Drop Calculator
Calculate voltage drop across electrical wire runs based on wire gauge, length, current, and material
Rebar Calculator
Calculate rebar quantity, weight, and cost for concrete slabs, footings, and walls
Gear Ratio Calculator
Calculate gear ratios, RPM, and torque for single and multi-stage gear trains
Electrical Load Calculator
Calculate total electrical load, amperage, and recommended breaker size for panels and circuits
Noise Level Comparison Calculator
Compare noise levels in decibels, calculate combined sound sources, and understand hearing safety
Metal Weight Calculator
Calculate weight of metal stock by shape, dimensions, and material type
Torque Converter
Convert between torque units including N·m, ft·lb, in·lb, kgf·m, and more
Dipole Antenna Length Calculator
Calculate half-wave, quarter-wave, and 5/8-wave antenna lengths for any frequency
SWR Calculator
Calculate standing wave ratio, return loss, reflection coefficient, and mismatch loss
Decibel (dB) Calculator
Convert between dB and power or voltage ratios, dBm to watts, and add dB values
Coax Cable Loss Calculator
Calculate signal attenuation in coaxial cable by type, length, and frequency
Axle Weight Distribution Calculator
Calculate front and rear axle loads based on vehicle weight, wheelbase, and cargo position