Engineering
Mechanical, civil, electrical, hydraulic, HVAC, and more engineering calculators.
Mechanical Engineering
Gears, torque, power transmission, springs, stress & strain, and rotational motion.
Gear Ratio Calculator
Find the gear ratio, output speed, torque, and mechanical advantage of a gear pair, in metric or imperial.
Gear Train Calculator
Calculate the overall ratio and output speed of a multi-stage compound gear train.
Torque Calculator
Calculate shaft torque from power and rotational speed in metric or imperial units.
Power Transmission Calculator
Calculate the mechanical power transmitted by a rotating shaft from torque and shaft speed.
Belt Length Calculator
Calculate open-belt length from pulley diameters and centre distance in metric or imperial units.
Pulley Ratio Calculator
Calculate driven pulley speed and ratio from driver and driven diameters.
Chain Drive Calculator
Calculate chain length and link count for roller-chain drives from pitch, sprocket teeth, and centre distance.
Bearing Life Calculator
Calculate L10 bearing fatigue life in revolutions and hours for ball and roller bearings.
Shaft Diameter Calculator
Find the minimum solid shaft diameter for a given torque and allowable shear stress using the torsion formula.
Spring Rate Calculator
Calculate the stiffness of a helical compression spring from wire diameter, coil diameter, and active coils.
Spring Constant Calculator
Calculate spring stiffness from force and displacement using Hooke’s law k = F ÷ x.
Flywheel Energy Calculator
Calculate the kinetic energy stored in a solid-disc flywheel from its mass, radius, and rotational speed.
Clutch Torque Calculator
Calculate friction clutch torque capacity from clamping force, friction coefficient, and mean radius.
Brake Torque Calculator
Calculate disc brake stopping torque from pad friction, clamping force, and effective rotor radius.
Mechanical Advantage Calculator
Calculate the mechanical advantage of a simple machine from its load and effort forces.
Lever Calculator
Calculate the load a lever can balance using the law of the lever: effort × effort arm = load × load arm.
Rotational Speed Calculator
Convert between RPM, rad/s, Hz, and deg/s instantly for any rotating shaft or motor.
RPM Calculator
Find a shaft or wheel’s rotational speed from its surface speed and diameter.
Angular Velocity Calculator
Convert rpm to rad/s and calculate linear (tangential) speed at any radius instantly.
Angular Acceleration Calculator
Calculate angular acceleration from initial and final RPM over a time interval in rad/s².
Centrifugal Force Calculator
Calculate the outward centrifugal force on a rotating mass from its mass, radius, and speed.
Moment of Inertia Calculator
Calculate the mass moment of inertia of discs, rings, spheres, and rods about their central axis.
Stress Calculator
Calculate normal (axial) stress from force and cross-sectional area, in MPa or ksi.
Strain Calculator
Calculate engineering strain from the change in length and original length, with percent and microstrain.
Young’s Modulus Calculator
Calculate Young’s modulus (elastic modulus) from stress and strain, in GPa, MPa or ksi, and Mpsi.
Shear Stress Calculator
Calculate shear stress from shear force and the area resisting shear, in MPa or ksi.
Shear Strain Calculator
Calculate shear strain γ from lateral displacement and height, with the shear angle in degrees.
Beam Deflection Calculator
Calculate the maximum deflection of simply supported and cantilever beams under point or uniform loads.
Civil & Construction
Concrete, rebar, bricks, asphalt, paint, tiling, and material quantity estimators.
Concrete Volume Calculator
Calculate concrete volume and weight for slabs — metric or imperial, with waste allowance.
Concrete Mix Calculator
Estimate cement bags, sand, and gravel for any concrete volume using standard mix ratios.
Cement Calculator
Calculate how many cement bags you need for any concrete pour by mix ratio and bag size.
Sand Calculator
Estimate how much sand you need to fill or cover an area — bedding, fill, or sandbox.
Gravel Calculator
Estimate gravel or aggregate needed to cover a driveway, path, or base course by area and depth.
Concrete Slab Calculator
Calculate concrete volume and cement, sand, and gravel quantities for any rectangular slab.
Brick Calculator
Estimate how many bricks you need for a wall — choose brick size, add a waste allowance, get a count.
Concrete Block Calculator
Estimate how many concrete blocks you need for a wall — pick block size, add waste, get a count.
Mortar Calculator
Estimate cement bags, sand volume, and mortar quantity for brick and blockwork walls.
Rebar Calculator
Estimate rebar quantities for a rectangular slab — bar counts, total length, and steel mass.
Earthwork Calculator
Estimate cut or fill earthwork volume and in-situ soil mass for a rectangular area.
Excavation Calculator
Estimate excavation (bank) volume and the loose hauled volume after soil bulking.
Asphalt Calculator
Calculate tonnes of asphalt to pave a driveway, road, or car park from length, width, and thickness.
Road Base Material Calculator
Estimate compacted crusher-run aggregate tonnage for road base and sub-base construction.
Pavement (Paver) Calculator
Count how many paving blocks or slabs you need to cover an area, with a waste allowance.
Roofing Calculator
Calculate sloped roof area and shingle bundles from the building footprint and roof pitch.
Tile Calculator
Calculate how many tiles you need for a room or wall — including waste and boxes required.
Paint Calculator
Calculate how much paint you need for a wall — enter dimensions, coats, and paint type.
Stair Calculator
Calculate the number of steps, riser height, and total run for a staircase, in metric or imperial.
Ramp Calculator
Calculate ramp run, sloped length, slope percentage, and angle from a rise and 1:n slope ratio.
Drainage (Rational Method) Calculator
Estimate peak stormwater runoff with the Rational Method to size gutters, drains, and culverts.
Footing Concrete Calculator
Estimate concrete volume and mix materials for rectangular pad footings.
Electrical Engineering
Ohm’s law, power, energy cost, circuits, solar, batteries, and LED resistors.
Ohm’s Law Calculator
Solve for voltage, current, or resistance with Ohm’s law V = I × R, plus power dissipation.
Voltage Calculator
Calculate voltage from current and resistance using Ohm’s law, plus dissipated power.
Current Calculator
Calculate electrical current from voltage and resistance using Ohm’s law, plus power.
Resistance Calculator
Calculate electrical resistance from voltage and current using Ohm’s law, plus power.
Electrical Power Calculator
Calculate electrical power in watts using voltage, current, or resistance with three formulas.
Energy Consumption Calculator
Calculate how many kWh an appliance uses per day, month, or year from its wattage and run time.
Electricity Cost Calculator
Calculate the daily, monthly, and yearly cost of running any appliance from its wattage and rate.
Voltage Drop Calculator
Calculate voltage drop and percentage loss along a cable run for single-phase or three-phase systems.
Transformer Calculator
Calculate secondary voltage, turns ratio, and secondary current for an ideal transformer.
Transformer Turns Ratio Calculator
Calculate the turns ratio Np:Ns from winding counts or from primary and secondary voltages.
Capacitor Calculator
Calculate the energy stored in a capacitor or its capacitive reactance at any frequency.
Inductor Calculator
Calculate the energy stored in an inductor or its inductive reactance at any frequency.
LED Resistor Calculator
Calculate the series resistor value and power rating needed to safely drive an LED.
RC Circuit Calculator
Calculate the RC time constant and cutoff frequency for any resistor–capacitor circuit.
RL Circuit Calculator
Calculate the RL time constant τ = L ÷ R and settling time for a series resistor–inductor circuit.
RLC Circuit Calculator
Calculate the resonant frequency, quality factor, and bandwidth of a series RLC circuit.
Power Factor Calculator
Calculate power factor, phase angle, and reactive power from real and apparent power.
Three-Phase Power Calculator
Calculate real and apparent power in balanced three-phase AC systems from line values.
Single-Phase Power Calculator
Calculate real power in watts for a single-phase AC circuit from voltage, current, and power factor.
Battery Capacity Calculator
Convert amp-hours and voltage to watt-hours to compare batteries of any voltage on equal terms.
Battery Life Calculator
Estimate battery runtime from capacity, load current, depth of discharge, and system efficiency.
Solar Panel Output Calculator
Estimate daily, monthly, and yearly solar energy output from your panel array.
Solar Array Sizing Calculator
Calculate how many solar panels you need to meet your daily energy load.
Inverter Size Calculator
Calculate the recommended inverter size for your load with a margin for losses and headroom.
Generator Size Calculator
Calculate the recommended generator size from running watts, motor surge watts, and a margin.
Hydraulic & Fluid
Pipe flow, pumps, pressure, head loss, tanks, and open-channel flow.
Flow Rate Calculator
Calculate volumetric flow rate through a circular pipe from its inner diameter and flow velocity.
Pipe Flow Calculator
Calculate volumetric flow through a full-bore circular pipe from its diameter and flow velocity.
Water Flow Calculator
Calculate water flow through a pipe or outlet from its diameter and water velocity.
Pipe Velocity Calculator
Calculate the flow velocity inside a circular pipe from volumetric flow rate and inner diameter.
Pipe Diameter Calculator
Find the minimum pipe inner diameter for a required flow rate at a target velocity.
Water Pressure Calculator
Calculate static water pressure from a column height using P = ρ·g·h, in metric or imperial.
Water Demand Calculator
Calculate average daily water demand and peak flow for a population from per-capita usage.
Pump Power Calculator
Calculate hydraulic and shaft power for a pump from flow rate, head, and efficiency.
Pump Efficiency Calculator
Calculate pump efficiency from flow rate, total head, and shaft power.
Head Loss Calculator
Calculate pipe friction head loss with the Darcy–Weisbach equation.
Pressure Loss Calculator
Calculate pipe pressure loss using the Darcy–Weisbach equation for any flow, pipe size, and friction factor.
Hydraulic Power Calculator
Calculate hydraulic power from system pressure and flow rate using P = ΔP × Q.
Hydraulic Cylinder Calculator
Calculate hydraulic cylinder push force and extension speed from pressure, bore, and flow rate.
Hydraulic Force Calculator
Calculate the output force of a hydraulic piston from fluid pressure and piston diameter.
Hydraulic Pump Flow Calculator
Calculate hydraulic pump output flow from displacement, speed, and volumetric efficiency.
Hydraulic Motor Calculator
Calculate hydraulic motor output torque from pressure drop, displacement, and mechanical efficiency.
Reservoir Capacity Calculator
Calculate the storage volume of cylindrical or rectangular reservoirs and tanks.
Water Tank Calculator
Calculate water tank capacity for cylindrical or rectangular tanks and estimate fill time.
Irrigation Water Calculator
Calculate irrigation water volume and watering time from area, application depth, and flow rate.
Open Channel Flow Calculator
Calculate flow rate in open channels with Manning’s equation from roughness, area, radius, and slope.
HVAC & Thermal
Cooling and heating loads, BTU, airflow, duct sizing, and heat transfer.
Cooling Load Calculator
Estimate the cooling load for a room by floor area and room type, in BTU/h, kW, and tons.
Heating Load Calculator
Estimate the heating load for a room or building from floor area and insulation level.
HVAC Sizing Calculator
Estimate air-conditioner or heat-pump capacity in tons from conditioned area and application.
BTU Converter
Convert heating and cooling power between BTU/h, watts, kilowatts, and refrigeration tons.
Air Flow (CFM) Calculator
Calculate the airflow (CFM) needed to carry a sensible cooling load over a temperature difference.
Duct Size Calculator
Calculate the round duct diameter needed from airflow and air velocity for HVAC design.
Ventilation (Air Changes) Calculator
Calculate required ventilation airflow from room dimensions and air changes per hour.
Heat Transfer Calculator
Calculate heat flow through walls and materials using a U-value or thermal conductivity.
Heat Loss Calculator
Calculate fabric heat loss through walls, roofs, and windows using the U·A·ΔT formula.
Heat Gain Calculator
Estimate conductive heat gain through a wall, roof, or floor from U-value, area, and ΔT.
Manufacturing & Machining
Cutting speed, feed rate, CNC speeds, tool life, and material removal rate.
Cutting Speed Calculator
Calculate surface cutting speed (Vc) from tool diameter and spindle RPM for turning and milling.
CNC Speed (RPM) Calculator
Calculate the spindle speed (RPM) for a CNC operation from cutting speed and tool diameter.
Feed Rate Calculator
Calculate CNC table feed rate from spindle speed, feed per tooth, and number of flutes.
Machining Time Calculator
Calculate cutting time from cut length, feed rate, and number of passes for CNC and manual machining.
Tool Life Calculator
Calculate cutting tool life from Taylor’s equation V·Tⁿ = C for machining operations.
Material Removal Rate Calculator
Calculate the volume of material cut per minute for turning and milling operations.
Milling Calculator
Calculate cutting speed, table feed rate, and material removal rate for milling operations.
Turning Calculator
Calculate cutting speed, feed rate, and material removal rate for CNC and manual lathe turning operations.
Drilling Calculator
Calculate spindle speed, feed rate, and drilling time from drill diameter, cutting speed, and feed.
Production Rate Calculator
Calculate parts per hour, per shift, and per day from cycle time and line efficiency.
Industrial Engineering
Takt and cycle time, OEE, EOQ, safety stock, queues, and throughput.
Takt Time Calculator
Calculate the pace of production needed to meet customer demand — available time divided by units required.
Cycle Time Calculator
Calculate the average time to produce one unit from net production time and units made.
Production Capacity Calculator
Calculate maximum unit output from available time, cycle time, and number of machines or lines.
OEE Calculator
Calculate Overall Equipment Effectiveness from availability, performance, and quality rates.
Economic Order Quantity Calculator
Find the optimal order quantity that minimises total inventory cost by balancing ordering and holding costs.
Process Capability Calculator
Calculate Cp and Cpk to measure how well your process meets specification limits.
Safety Stock Calculator
Calculate safety stock and reorder point to buffer against demand variability during lead time.
Reorder Point Calculator
Calculate the inventory level that triggers a new order so stock arrives before you run out.
Inventory Turnover Calculator
Calculate how many times you sell and replace inventory per year using COGS and average inventory value.
Little’s Law Calculator
Compute WIP, throughput, or flow time using Little’s Law for any stable process or queue.
Labor Productivity Calculator
Calculate output per labor hour to measure and track workforce efficiency over time.
Environmental Engineering
Carbon footprint, water use, emissions, air quality, noise, and rainwater harvesting.
Carbon Footprint Calculator
Estimate your annual CO₂ emissions from electricity, driving, and flights, and see how many trees offset them.
Fuel CO₂ Emissions Calculator
Calculate CO₂ emissions from burning petrol, diesel, LPG, or jet fuel by volume consumed.
Electricity Emissions Calculator
Calculate the CO₂ emissions from electricity use based on your regional grid emission factor.
Water Usage Calculator
Calculate total household or project water consumption from daily per-person use, people, and days.
Rainwater Harvesting Calculator
Estimate how much rainwater your roof can collect each year based on area, rainfall, and runoff coefficient.
Recycling Rate Calculator
Calculate your waste diversion rate and per-capita waste from recycled and total waste figures.
Air Quality Index Calculator
Convert a PM2.5 concentration into a US EPA Air Quality Index (AQI) score and health category.
Noise Level Calculator
Calculate combined decibel levels from two sound sources or sound level at a given distance from a point source.
Solar Energy Yield Calculator
Estimate annual solar energy production and CO₂ offset from system size and peak sun hours.
Tree Offset Calculator
Calculate how many trees you need to plant to offset a given amount of CO₂ emissions per year.
Emission Intensity Calculator
Calculate kg CO₂ emitted per unit produced to benchmark and compare production efficiency.