Engineering & construction
517 engineering and construction calculators: electrical circuits, mechanics, materials, structures and building quantities. Results with the formula and units in view, so you can check a design before you build it, free in your browser.
Horizontal Curve Calculator
Give a 500 m radius and a 60-degree deflection and you get the tangent length, the arc length and the external distance of the curve, all in metres.
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Height of instrument calculator
With a benchmark at 100 m and a backsight of 1.245 m, the height of instrument is 101.245 m. Enter the benchmark elevation and the backsight reading to start a…
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Map scale from measurement calculator
Turn a ruler measurement into a map scale: 2 cm on the map that span 1 km on the ground give 1:50000.
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Modulus of toughness estimate
Estimate how much energy a material absorbs before it breaks: 250 MPa yield, 450 MPa ultimate and a fracture strain of 0.3 give 105 MJ/m³.
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Nozzle exit velocity calculator
Estimate how fast liquid leaves a tank opening: with 5 m of head, Torricelli's rule gives about 9.90 m/s.
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Heat exchanger NTU effectiveness calculator
Find how close a heat exchanger gets to the maximum possible heat transfer: NTU 2 with a capacity ratio of 0.5 in counterflow gives an effectiveness of just…
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Percent Elongation Calculator for Tensile Specimens
Measure how far a specimen stretched before breaking: a gauge length that grows from 50 mm to 62.5 mm has lengthened 12.5 mm, an elongation of 25 %.
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Pipe flow velocity calculator
Find how fast fluid moves on average in a full round pipe: 0.01 m³/s through a 0.1 m bore travels at just over one and a quarter metres per second.
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Plastic Moment Capacity Calculator
Get the full plastic bending capacity of a section: a plastic modulus of 500000 mm³ with a yield strength of 355 MPa gives 177.5 kN·m.
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Solid Shaft Polar Moment of Inertia Calculator
Get the polar moment of inertia of a solid round shaft from its diameter alone: a 50 mm shaft has a J of just over six hundred thousand mm⁴.
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Pump Total Dynamic Head Calculator
Add up what a pump must overcome: 18 m of lift, 7.5 m of friction loss and an outlet speed of 2.4 m/s come to just under twenty-six metres of total head.
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Thermal resistance series calculator
Stack up the thermal resistance of a layered wall: 0.08 m of mineral wool at 0.04 W/(m·K) alone adds 2 m²·K/W, far more than the brick and gypsum board around…
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Screw jack MA calculator
See how much a screw jack multiplies your effort: a 0.5 m handle on a 0.005 m pitch gives an ideal advantage of 2π times 100, so each newton of effort lifts…
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Shaft critical speed calculator from static deflection
Estimate where a rotating shaft starts to whirl: 2.5 mm of static deflection puts the first critical speed just under six hundred rpm.
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Slider-Crank Piston Position Calculator
Locate a piston at any crank angle: with a 50 crank radius and a 150 rod, top dead centre sits at 200 and the stroke is 100, and at 60° the piston has dropped…
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Soderberg fatigue criterion calculator
Check whether a cyclic load stays inside the Soderberg line: 120 alternating and 80 mean against a 300 endurance limit and 500 yield give a utilization of 0.56…
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Steel plate weight calculator
Weigh a plate before you order it: a 2 m by 1 m sheet, 0.01 m thick, in mild steel at 7850 kg/m³ has a volume of 0.02 m³ and weighs 157 kg.
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Motor Synchronous Speed Calculator
Find how fast the magnetic field turns in an AC motor: four poles at 50 Hz give 1500 rpm, one revolution every 40 ms.
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Thermal strain calculator
See how much a material grows when heated: at 12 ppm/K, warming from 20 °C to 70 °C gives a strain of 0.0006, or 600 microstrain, so each unrestrained metre…
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Torque from power and speed calculator
Turn a machine's power and speed into shaft torque: 15 kW at 1450 rpm puts just under a hundred newton-metres on the shaft.
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Shaft Torsional Shear Stress Calculator
Check how hard a torque loads a round shaft: 1200 N·m on a solid shaft of 25 mm radius produces just under forty-nine megapascals of shear at its surface.
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Transformer turns ratio and voltage calculator
Find what voltage a winding delivers: 230 V on a 1000-turn primary with a 100-turn secondary gives a turns ratio of 10 and an ideal 23 V output, so it is a…
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Trapezoidal channel hydraulic radius
A channel 10 wide at the bed, 2 deep and with 1.5:1 banks has a flow area of 26 and a hydraulic radius of about 1.510653, in the same length units you typed.
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Trigonometric leveling calculator
With the instrument 1.55 above the ground, a 5.5° vertical angle, 120 of horizontal distance and a target 1.8 high, the ground-to-ground difference is about…
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Truss joint two-member force calculator
With one bar along the x-axis, one pointing straight up and a downward load of 100 on the joint, the vertical bar carries 100 in tension and the horizontal one…
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Hydraulic turbine power calculator
With 2.5 m³/s of flow, 40 m of net head, 88% efficiency and fresh water, a turbine delivers about 863 kW out of 980665 W of hydraulic power.
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Feeder voltage drop percentage calculator
A drop of 7.2 V on a 240 V feeder is 3%: enter the voltage loss you already calculated and the nominal system voltage, and get the percentage your design review…
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Vertical curve elevation calculator
On a curve 200 long that starts at elevation 100 and goes from a 2% climb to a 1% fall, the point 75 from the start sits at 101.078125, with a grade of 0.875%.
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Feeder voltage regulation calculator
A feeder that reads 240 V at no load and 230 V at full load has a voltage regulation of about 4.3478%, from a 10 V change.
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Interior Wall Surface Temperature Calculator
With 21 °C indoors, a wall U-value of 0.35, an inside film coefficient of 7.7 and a 25 K difference to outside, the inner wall face sits at 19.863636 °C.
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V-notch weir flow calculator
A 90° V-notch with 0.25 m of head above the vertex passes 45.098832115 litres per second with the standard coefficient of 0.611, and you can enter the…
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Wheel and axle mechanical advantage calculator
A wheel with a radius of 30 on an axle with a radius of 5 multiplies your effort by 6, in any length unit as long as both match.
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Acceleration from distance and time calculator
An object starting from rest that covers 100 metres in 10 seconds is accelerating at 2 m/s²: enter the distance and the time, and the calculator applies twice…
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Initial velocity for distance calculator
To cover 100 m in 5 s while accelerating at 2 m/s², an object must start at 15 m/s. Enter the signed displacement, the constant acceleration and a non-zero time…
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Reaction distance calculator
At 13.89 m/s with a 1.5 s reaction time, a car covers 20.835 m before the brakes even begin to work.
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Relative velocity 2D calculator
A body moving at (10, 0) seen from one moving at (3, 4) has a relative velocity of (7, −4): 7 along the horizontal and 4 downward.
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Torricelli equation calculator
Starting at 10 m/s and accelerating at 2 m/s² over 50 m, a body reaches 17.320508075689 m/s. Enter initial velocity, acceleration and displacement to get the…
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Vertical throw flight time calculator
A ball thrown straight up at 24.5 m/s under 9.80665 m/s² gravity stays in the air for 4.996609443592 s before passing its launch height again.
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Angle of repose calculator
A static friction coefficient of 0.5 means a block starts to slide at 26.565051177078 degrees: the calculator takes the arctangent of μₛ and gives the angle of…
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Force resolution calculator
A 100 N force at 30° has a vertical component of exactly 50 N: enter any magnitude and angle to get both components, with signs that show left, right, up or…
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Incline friction to prevent sliding calculator
A block on a 30-degree slope needs a static friction coefficient of at least 0.57735026919 to stay put.
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Mean velocity under uniform acceleration
An object that speeds up steadily from 10 m/s to 30 m/s has a mean velocity of 20 m/s over that stretch.
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Projectile range on an incline calculator
Fire at 30 m/s and 45° toward a ramp that rises 15° and see exactly where the projectile lands: the distance along the slope, the horizontal distance, the…
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Complementary angle range calculator
Type 20 m/s and 30° and the calculator also shows the 60° partner: both land at the same distance, while the steeper path stays longer in the air and climbs…
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Tension in accelerating cord calculator
On a smooth floor, pulling a 3 kg block with 10 N while it tows a 2 kg block gives both an acceleration of 2 m/s² and a cord tension of 4 N.
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Two-rope tension calculator
A 100 N weight hanging from ropes at 30° and 60° puts 50 N in the first rope and 86.60254 N in the second.
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Centrifuge g-force calculator
A rotor radius of 10 cm at 10000 rpm gives 11180 g of relative centrifugal force. Enter the distance from the axis to the sample and the speed shown on your…
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Kinetic energy ratio calculator
Going from 10 to 20 km/h doubles the speed but quadruples the kinetic energy. Enter a reference speed and a comparison speed in the same unit to get the speed…
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Max speed on flat curve calculator
On a flat curve of 50 m radius with a friction coefficient of 0.7, the fastest speed before the tyres slide is 18.52970588 m/s.
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Output power from efficiency calculator
Find what a motor, drive or converter really delivers: 750 W in at 84 % efficiency gives 630 W of useful output, with the other 120 W lost.
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Pendulum speed at the bottom calculator
Release a pendulum bob 1.25 m above its lowest point and it passes the bottom at just under 5 m/s, with no mass needed.
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Screw jack mechanical advantage calculator
A 0.5 m handle on a screw with a 0.005 m pitch gives an ideal mechanical advantage of 2π × 100: your hand travels a whole circle while the load rises one pitch.
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Maximum static friction calculator
With a static coefficient of 0.45 and a normal force of 320 N, surfaces can hold up to 144 N before they slip.
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Work-energy theorem calculator
A 2 kg body speeding up from 3 to 5 m/s goes from 9 J to 25 J of kinetic energy, so the net work on it is 16 J.
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Angular displacement calculator
A body spinning at 10 rad/s with an angular acceleration of 2 rad/s² sweeps 75 radians in 5 seconds: the calculator adds ω₀t and ½αt² and shows each step.
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1D momentum conservation calculator
A 2 kg cart at 3 m/s meets a 1 kg cart at −1 m/s; if the first ends at 1 m/s, the second leaves at 3 m/s.
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Explosion fragment velocity calculator
If a 2 kg piece flies off at 12 m/s, a 3 kg piece recoils at -8 m/s: the calculator finds the second fragment's velocity, with its direction shown as a sign…
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Impulse on bouncing ball calculator
A 0.5 kg ball that hits the floor at 4 m/s and rebounds at 3 m/s receives an impulse of 3.5 N·s, because its velocity changes by 7 m/s.
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Point Mass Moment of Inertia Calculator
A 3 kg mass sitting 2 m from the axis has a moment of inertia of 12 kg·m²: enter the mass and its perpendicular distance and get I = mr² straight away.
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Ring moment of inertia calculator
A thin ring of 3 kg and radius 4 m has a moment of inertia of 48 kg·m² about its centre, because all of its mass sits on the rim.
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