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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Metal Weight CalculatorCalculate the weight of metal bars, tubes and plates from dimensions and material density. Supports steel, aluminium, copper, brass and stainless.
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Gas Line CalculatorEnter total BTU, pipe length (feet), and pressure (inches water column) to get the recommended gas pipe size and estimated flow rate.
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Factor of Safety CalculatorCalculate the factor of safety (FoS) from ultimate or yield stress divided by allowable stress. Free engineering safety factor calculator with margin of safety.
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Air Density CalculatorCalculate the density of dry air from pressure and temperature using the ideal gas law (ρ = P / (R·T), R = 287.058 J/kg·K).
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Air Flow Rate Calculator From Pressure and DiameterCalculate air flow rate from pressure difference and pipe diameter. Get volumetric flow in m³/s, m³/h and CFM plus velocity using Bernoulli equation.
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Weld Metal Weight CalculatorCalculate deposited weld metal weight for a fillet weld from leg size, length and material density. Metric, with cross-sectional area and volume.
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Round Pool Volume CalculatorCalculate the water volume of a round (circular) swimming pool in US gallons and cubic feet from its diameter and average depth.
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Viscosity Index CalculatorCalculate Viscosity Index easily with kinematic viscosity values at 40°C and 100°C. Determine oil performance and viscosity-temperature relationship for efficient lubricant analysis and selection.
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Wire Gauge (AWG) CalculatorConvert American Wire Gauge (AWG) to conductor diameter and cross-sectional area, and estimate copper wire current capacity (ampacity) by density.
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Hooke's Law Calculator (F = -kx)Solve Hooke's Law F = -kx for spring force, spring constant, displacement, or the acceleration of an attached mass, with full unit conversion.
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18650 Battery Pack CalculatorCalculate the voltage, capacity (Ah), total cell count and energy (Wh) of an 18650 battery pack from any series-parallel (SxP) configuration.
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Crash / Impact Force CalculatorCalculate the average impact force of a crash or collision from mass, impact speed, and stopping distance. Get force in N, kN, energy, and g-force.
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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.
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.
