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Engineering calculators
75 free calculators for engineering design and analysis. Calculate instantly without an account. Log in only when you want to save calculations to a project.
Mass from Density × Volume
Calculate mass from material density and physical volume.
Density
Calculate density from mass and volume.
Volume from Mass ÷ Density
Calculate material volume from mass and density.
Percentage Change
Calculate percentage change between an original and a new value.
Force
Newton's second law: F = m × a.
Torque
Calculate torque from perpendicular force and lever arm.
Work
Calculate mechanical work from force and displacement.
Mechanical Power
Calculate average power from work and elapsed time.
Kinetic Energy
Calculate translational kinetic energy.
Momentum
Calculate linear momentum.
Centripetal Force
Calculate centripetal force for circular motion.
Normal Stress
Calculate axial normal stress from force and cross-sectional area.
Strain
Calculate engineering strain from extension and original length.
Factor of Safety
Calculate factor of safety from allowable strength and working stress.
Axial Deformation
Calculate elastic axial extension δ = FL / AE.
Bending Stress
Calculate bending stress σ = My / I.
Ohm's Law — Voltage
Calculate voltage from current and resistance.
Ohm's Law — Current
Calculate current from voltage and resistance.
Ohm's Law — Resistance
Calculate resistance from voltage and current.
Electrical Power
Calculate electrical power P = VI.
Electrical Energy
Calculate electrical energy from power and time.
Battery Energy
Estimate nominal battery energy from voltage and capacity.
Battery Runtime
Ideal runtime from usable capacity and average current.
Wing Loading
Calculate mass-based wing loading.
Aspect Ratio
Calculate wing aspect ratio AR = b² / S.
Dynamic Pressure
Calculate q = ½ρV².
Lift
Calculate aerodynamic lift L = ½ρV²SCₗ.
Drag
Calculate aerodynamic drag D = ½ρV²SCᴅ.
Stall Speed
Estimate stall speed from mass, air density, wing area and Cₗmax.
Reynolds Number
Calculate Reynolds number Re = ρVL / μ.
Pressure
Calculate pressure from normal force over area.
Volumetric Flow Rate
Calculate volumetric flow rate Q = Av.
Fluid Velocity from Flow Rate
Calculate average velocity v = Q / A.
Heat Energy
Calculate sensible heat energy Q = mcΔT.
Linear Thermal Expansion
Calculate length change ΔL = αLΔT.
Weight from Mass
Convert mass to gravitational weight using standard gravity.
Circle Area
Calculate circular area from diameter.
Rectangle Area
Calculate rectangular area from length and width.
Rectangular Volume
Calculate rectangular-prism volume from length, width and height.
Cylinder Volume
Calculate cylindrical volume from diameter and length.
Current from Power ÷ Voltage
Calculate electrical current from power and voltage.
Resistance from Power & Current
Calculate resistance from P = I²R.
Efficiency
Calculate output/input efficiency.
Hydrostatic Pressure
Calculate pressure increase from fluid density and depth.
Rectangular Second Moment of Area
Calculate the centroidal second moment of area of a rectangular section about its strong axis.
Circular Second Moment of Area
Calculate the centroidal second moment of area of a solid circular section.
Rectangular Section Modulus
Calculate elastic section modulus for a rectangular section about its strong axis.
Simply Supported Beam Deflection — Centre Load
Maximum deflection of a simply supported beam with a concentrated load at midspan.
Cantilever Deflection — End Load
Tip deflection of a cantilever beam under a concentrated end load.
Simply Supported Beam Deflection — UDL
Maximum deflection of a simply supported beam under a uniformly distributed load.
Euler Buckling Load
Estimate the elastic critical buckling load of a slender column.
Solid Shaft Torsional Stress
Maximum torsional shear stress in a solid circular shaft.
Solid Shaft Angle of Twist
Elastic twist of a solid circular shaft under torque.
Bearing Stress
Average bearing stress at a pin, bolt or fastener interface.
Voltage Divider
Calculate the unloaded output voltage of a two-resistor voltage divider.
Series Resistance
Equivalent resistance of three resistors connected in series.
Parallel Resistance — Two Branches
Equivalent resistance of two resistors connected in parallel.
RC Time Constant
Calculate the time constant τ = RC of a first-order resistor-capacitor circuit.
Capacitor Stored Energy
Calculate energy stored in a capacitor at a given voltage.
Resistive Heating
Calculate Joule heating power using P = I²R.
Battery Current from C-Rate
Calculate current associated with a battery capacity and specified C-rate.
Mass Flow Rate
Calculate mass flow rate from fluid density and volumetric flow rate.
Bernoulli Pressure
Estimate downstream static pressure using Bernoulli's equation including elevation change.
Darcy–Weisbach Pressure Loss
Calculate major pressure loss along a straight pipe from Darcy friction factor.
Hydraulic Power
Calculate ideal hydraulic power from pressure difference and volumetric flow rate.
Orifice Flow Rate
Estimate incompressible flow through an orifice from pressure difference.
Conduction Heat Transfer
Steady one-dimensional conduction through a uniform wall or plate.
Convective Heat Transfer
Estimate convection heat-transfer rate using Newton's law of cooling.
Conduction Thermal Resistance
Calculate thermal resistance through a uniform layer.
Convection Thermal Resistance
Calculate convective thermal resistance between a surface and fluid.
Radiative Heat Transfer
Net idealised thermal radiation exchange with a large surrounding environment.
Rotational Kinetic Energy
Calculate kinetic energy stored in a rotating body.
Spring–Mass Natural Frequency
Undamped natural frequency of a single-degree-of-freedom spring-mass system.
Lift Coefficient
Calculate aerodynamic lift coefficient from lift force, dynamic pressure and reference area.
Drag Coefficient
Calculate aerodynamic drag coefficient from drag force, dynamic pressure and reference area.
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