Physics and Engineering calculators cover applied science and design — material weights, fluid flow, air density, and gas-line sizing. Popular tools include the Metal Weight Calculator, Manning's Pipe Flow Calculator, Air Density Calculator, Pipe Weight Calculator, and Gas Line Calculator.
Enter your parameters below for an instant result, or open the Trending tab to see what engineers are calculating this week. Every calculator is free and works on any device.
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Resistivity CalculatorCalculate the electrical resistance of a wire from its resistivity, length, and cross-sectional area using R = ρL/A. Free, instant, accurate.
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Capacitive Voltage Divider CalculatorCalculate the output voltage of a resistive voltage divider using Vout = Vin × R2 / (R1 + R2). Also gives divider ratio, current and power.
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Running Amps and Startup Load CalculatorSize a generator by adding running watts plus the largest startup surge. Enter your appliances to find the minimum wattage and a recommended size.
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VinFast Charge Time from Amps CalculatorEstimate VinFast EV charging time from charger power (kW), battery capacity, and start/target charge percent. Quick, simple hours and minutes estimate.
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Dynamic Viscosity of Water CalculatorCalculate the minimum pipe diameter from volume flow rate and target flow velocity using D = √(4Q/πv). Get diameter in mm and m plus pipe area.
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Thin Rod Center of Mass CalculatorFind the center of mass of two particles along a line from their masses and positions using x_cm = (m₁x₁ + m₂x₂)/(m₁+m₂). Free physics tool.
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Speed of Sound in Water CalculatorCalculate the speed of sound in air using a = √(γRT). Enter temperature in °C to get the sonic speed in m/s, km/h, and mph instantly.
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Gallons per Minute from Meter or Bucket Test CalculatorCalculate gallons per minute (GPM) flow rate from a bucket fill test. Enter container volume and fill time in seconds to get GPM and GPH.
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Gravitational Potential Energy CalculatorCalculate gravitational potential energy with PE = m·g·h. Enter mass, gravity, and height to get the energy in joules instantly.
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Snow Load CalculatorCalculate roof snow load from snow depth and density, or the ASCE 7 flat-roof snow load using ground snow load and exposure, thermal and importance factors.
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Bolt Torque CalculatorCalculate the tightening torque for a bolt from the nut factor (K), target clamp force, and bolt diameter using T = K·F·d. Results in N·m, lb-ft, in-lb.
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Dog Raisin Toxicity CalculatorEstimate your dog's grape or raisin toxicity risk from amount eaten and body weight. Uses conservative toxic-dose thresholds. Not a substitute for a vet.
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Escape Velocity from a Planet and the Solar System CalculatorCompute escape velocity from a planet, the Sun, the Moon or an asteroid surface, plus the speed to escape the Solar System from its orbit. Pick a preset or enter values.
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Radioactivity (Becquerel) CalculatorCalculate radioactivity in becquerel (Bq) from the mass, half-life and molar mass of a pure radioisotope. Includes 23 isotopes and Bq per gram.
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Projectile Motion CalculatorCalculate projectile range, maximum height and time of flight from initial velocity, launch angle and gravity using classic kinematics formulas.
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Terminal Velocity CalculatorCalculate the terminal velocity of a falling object from its mass, drag coefficient, cross-sectional area and fluid density. Results in m/s, km/h and mph.
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Sound Distance Attenuation CalculatorCalculate how sound level drops over distance using the inverse-square law: L2 = L1 - 20·log10(r2/r1). Free dB attenuation calculator.
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Voltage Divider CalculatorCalculate the output voltage of a resistive voltage divider from Vin, R1 and R2. Also finds loop current and total power dissipated.
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Wire Resistance CalculatorCalculate the electrical resistance of a wire from its resistivity, length, and cross-sectional area using R = ρL/A. Free online tool.
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Darcy-Weisbach Head Loss CalculatorCalculate pipe friction head loss with the Darcy-Weisbach equation. Enter friction factor, length, diameter, velocity and gravity to get head loss in meters.
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Orbital Velocity CalculatorCalculate the orbital velocity of a satellite or planet from the central body's mass and orbital radius using v = √(GM/r). Free physics tool.
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Hydraulic Gradient CalculatorCalculate the hydraulic gradient (i = dh / L) from head loss and flow path length. Free dimensionless gradient and percent slope calculator for groundwater flow.
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Orifice Flow CalculatorCalculate volumetric flow through an orifice using Q = Cd·A·√(2gh). Enter discharge coefficient, area, head and gravity to get flow rate in m³/s.
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Reynolds Number CalculatorCalculate the Reynolds number from fluid density, velocity, characteristic length and viscosity to determine laminar, transitional or turbulent flow.
Frequently asked questions
What can I calculate with these physics and engineering tools?
Material and component weights, fluid mechanics such as open-channel and pipe flow, air and gas properties like density, and sizing calculations for lines and systems.
Are the results suitable for engineering work?
They apply standard equations and reference values and are great for estimates and checks. For designs that affect safety or code compliance, verify against the governing standard and have a qualified engineer review them.
Are these calculators free?
Yes — free, no sign-up, and they work on any device.
How do I make sure my units are right?
Check each input's unit label before entering values; mixing unit systems is the most common source of error in engineering calculations.
Which tools are most popular?
This page orders them by usage; the Trending tab shows what's rising this week.
