Mechanical Engineering Calculators
Calculators for mechanical and manufacturing work: power transmission, fastener torque, belt drives and threading. Each tool documents the formula and the friction or material factors it assumes.
Power Transmission
Gears, belts, chains and pulleys — speed ratios, torque conversion and drive geometry.
- Gear Ratio CalculatorCalculate gear ratio from teeth counts, with output RPM and torque including mesh efficiency. Supports single-stage and explained multi-stage use.
- Gear Geometry CalculatorCalculate spur gear geometry from module and tooth count: pitch, outside and root diameters, circular pitch and tooth depth. ISO module system.
- Pulley RPM CalculatorCalculate driven pulley RPM from diameters and driver speed, with belt speed check. For V-belt and flat-belt drives using pitch diameters.
- Pulley System CalculatorCalculate belt-drive speed ratio, output RPM, torque multiplication and belt speed from driver/driven pulley diameters — with the V-belt limits shown.
- Belt Length CalculatorCalculate open-belt length from two pulley diameters and center distance, with speed ratio. Classical V-belt/flat-belt geometry, metric and imperial output.
- Chain Length CalculatorCalculate roller chain length from sprocket teeth and center distance, in pitches, links, mm and inches. Recommends even link counts.
- Torque to Power CalculatorConvert torque and RPM to mechanical power in kW, hp and lb·ft. Includes the exact formulas and the difference between shaft, brake and rated power.
Fasteners & Threading
Bolt torque, tap drill sizes and torque wrench corrections.
- Bolt Torque CalculatorCalculate tightening torque for metric bolts by grade and size, with preload at 75% of proof load and dry or lubricated friction. Includes the K-factor model.
- Tap Drill CalculatorCalculate tap drill size for metric threads at any thread engagement percentage, with the standard 75% recommendation and nearest drill bit size.
- Torque Wrench Extension CalculatorCorrect torque wrench settings when using extensions or crowfoot wrenches in line with the handle. Get the reduced setting that hits the target.
Engine & Displacement
Engine displacement, compression ratio and bore/stroke calculations.
- Engine Displacement CalculatorCalculate engine displacement in cc, liters, cubic inches (CID) and CI from bore, stroke and cylinder count. Per-cylinder volume included.
- Compression Ratio CalculatorCalculate static compression ratio from swept volume, chamber volume, gasket volume and piston dome/dish. Essential engine building math.
Machine Elements
Bearings, springs, material weight and structural considerations.
- Bearing Life CalculatorCalculate ball or roller bearing L10 life from dynamic load rating, applied load and speed. Hours, revolutions and years at the duty point.
- Spring Rate CalculatorCalculate compression spring rate from wire diameter, coil diameter and active coils. N/mm and lbf/in, with spring index guidance.
- Metal Weight CalculatorCalculate the weight of steel, aluminum, stainless, brass and other metals in round bar, square bar, plate and tube shapes. kg and lb.
Beams & Shafts
Cantilever deflection and stress, shaft torsion capacity and machine efficiency.
- Cantilever Beam CalculatorCalculate tip deflection and maximum bending stress for a steel cantilever with an end load. Rectangular section, with utilization against 250 MPa yield.
- Simply Supported Beam CalculatorCalculate midspan deflection and bending stress for a steel simply supported beam with a center point load — with the support-condition comparison explained.
- Shaft Torsion CalculatorCalculate shear stress in a solid round shaft from torque, or the torque capacity at an allowable stress. Power at 1750 RPM included for motor sizing.
- Machine Efficiency CalculatorCalculate efficiency from measured input and output power, with the loss in watts that becomes heat. Motor load-point guidance included.
Materials & Statics
Stress, strain, elastic modulus and power in linear motion.
- Hooke's Law CalculatorSolve Hooke's law: stress (F/A), strain (ΔL/L) and Young's modulus — enter force and area to predict elongation, or enter elongation to measure E.
- Power from Force CalculatorCalculate mechanical power from force and linear velocity: watts, kW and hp — the linear-motion twin of torque-to-power for conveyors, hoists and actuators.
Fluid Power
Hydraulic cylinders, pump power and fluid mechanics.
- Hydraulic Cylinder CalculatorCalculate hydraulic cylinder force from bore, rod and pressure, for both extend and retract strokes. kN and lbf, with the annulus area explained.
- Pump Power CalculatorCalculate pump hydraulic and shaft power from flow, head and efficiency. Water horsepower, brake horsepower and motor sizing in kW and hp.
Design guide
How these calculations fit together in real projects — the order to run them in, and the decisions each one answers.