Engineering Calculators & Tools
Civil, Mechanical, Electrical, and Computer Engineering calculators.
Engineering work leans on standard formulas applied carefully and consistently. These calculators cover common civil, mechanical, and electrical tasks, and each shows the equation so you can trace the result back to first principles.
ABV Calculator
Calculate alcohol by volume from original and final gravity. Free calculator with instant calculations, the underlying formula, and an easy-to-follow example.
Air Changes Per Hour Calculator
Calculate ACH from airflow and room volume.
Arc Flash Incident Energy Estimator
A simplified arc-flash incident energy estimate.
Floor Area Ratio (FAR) Calculator
Calculate FAR and allowable floor area.
Area & Volume Calculator
Calculate area and volume of a box-shaped space.
Solar Array Layout Calculator
Calculate panels per string and total array layout.
Asphalt Tonnage Calculator
Calculate asphalt tonnage for a paving area.
Batch Scaling Calculator
Scale a production batch up or down.
Battery Life Calculator
Calculate how long a battery will last from capacity and current draw.
Battery Backup (UPS) Calculator
Estimate UPS runtime from battery and load.
Battery Bank Sizing Calculator
Size a battery bank for a daily energy need.
Beam Deflection (UDL) Calculator
Max deflection of a simply-supported beam under uniform load.
Beam Deflection Calculator
Calculate max deflection of a simply-supported beam under a central point load.
Bending Moment Calculator
Max bending moment for point and uniform loads.
Bid Comparison Calculator
Compare contractor bids by total and per-unit cost.
Bolt Shear Capacity Calculator
Estimate the shear capacity of a bolt.
Bolt Torque Calculator
Calculate tightening torque for a target bolt preload.
Bill of Materials Cost Calculator
Total a bill of materials from line items.
Room BTU Calculator
Estimate cooling/heating BTU needed for a room.
Cable Pulling Tension Calculator
Estimate the tension to pull cable through a straight conduit.
Capacitor Calculator
Calculate charge, voltage, or capacitance.
Capacitor Code Calculator
Decode a 3-digit ceramic capacitor code to capacitance.
CFM Airflow Calculator
Calculate required airflow (CFM) for a room and air changes.
Wire Ampacity Reference
Look up the typical ampacity of common copper wire sizes.
Column Buckling Calculator
Calculate Euler critical buckling load of a column.
Concrete Calculator
Calculate concrete volume for a slab.
Concrete Mix Calculator
Calculate cement, sand and gravel for a concrete volume.
Concrete Pour Calculator
Calculate concrete for footings, columns or slabs.
Conduit Fill Calculator
Check conductor fill percentage in a conduit.
Deck Board Calculator
Calculate deck boards needed for an area.
Drainage Flow Calculator
Estimate stormwater runoff using the Rational Method.
Drain Slope Calculator
Calculate drain pipe fall over a run.
Duct Sizing Calculator
Find duct size for an airflow at a target velocity.
DWV Fixture Unit Calculator
Total drainage fixture units for plumbing fixtures.
DWV Pipe Size Planner
Suggest a drain pipe size from total fixture units.
Earthwork Cut & Fill Calculator
Calculate cut/fill volume and the balance.
Electrical Job Cost Calculator
Estimate the price of an electrical job.
Energy Cost Calculator
Calculate the cost to run a device from its energy use.
Fiber Optic Link Budget Calculator
Calculate optical power budget and margin for a fiber link.
Plumbing Fixture Summary
Summarize fixture count and water demand.
Flooring Calculator
Calculate flooring needed for a room with waste.
Flow Velocity Calculator
Calculate fluid velocity from flow rate and pipe area.
Fluid Flow Rate Calculator
Calculate volumetric flow from velocity and area.
Foundation Bearing Calculator
Check footing size against soil bearing capacity.
Wall Framing Calculator
Calculate studs needed for a wall.
Gas Cylinder Duration Calculator
Estimate how long a gas cylinder will last.
Gas Pipe Sizing Calculator
Estimate gas pipe capacity from BTU load and length.
Gas Pressure Drop Calculator
Estimate pressure drop in a natural gas line.
Gear Ratio Calculator
Calculate gear ratio and output speed/torque.
Generator Sizing Calculator
Estimate generator kW needed for your loads.
Gravel Calculator
Calculate gravel volume and weight for an area.
Heat Load Calculator
Calculate heat load from a temperature difference and U-value.
HVAC Load Calculator
Estimate heating/cooling load with a simplified Manual-J approach.
HVAC Quote Calculator
Estimate an HVAC installation quote.
HVAC Upgrade ROI Calculator
Calculate payback period for an HVAC efficiency upgrade.
Inductor Energy Calculator
Calculate energy stored in an inductor.
kWh Energy Converter
Convert energy between kWh, joules, BTU and calories.
Labor Burden Calculator
Calculate the fully-burdened cost of an employee.
Land Area Converter
Convert land area between m², hectares, acres and ft².
LCL Freight Calculator
Calculate chargeable weight for LCL ocean freight.
Lighting Design Calculator
Calculate the number of fixtures for a target light level.
Electrical Load Converter
Convert between watts, amps, volts and horsepower.
Load Demand Calculator
Apply a demand factor to a connected electrical load.
Material Takeoff Calculator
Total material cost from quantity, unit price and waste.
Motor Speed Calculator
Calculate AC motor synchronous speed from poles and frequency.
Mulch Calculator
Calculate mulch volume needed for a garden bed.
Occupancy Load Calculator
Calculate occupant load from area and use type.
Ohm's Law Calculator
Solve for voltage, current, resistance or power. Free calculator with instant calculations, the underlying formula, and an easy-to-follow example.
Panel Load Balance Calculator
Balance circuit loads across two panel legs.
Pipe Sizing Calculator
Find pipe diameter for a flow at a target velocity.
Plumbing Job Estimate
Estimate the cost of a plumbing job.
Electrical Power Calculator
Calculate electrical power from voltage and current.
Power Factor Calculator
Calculate power factor from real and apparent power.
Pipe Pressure Drop Calculator
Estimate pressure drop using Hazen-Williams.
Pressure Loss Calculator
Convert head loss to pressure and total dynamic head.
Project Margin Calculator
Calculate gross margin and markup from cost and price.
Pump Operating Point Calculator
Find where a pump curve meets the system curve.
Pump Horsepower Calculator
Calculate the hydraulic and brake horsepower of a pump.
Ramp Slope Calculator
Calculate ramp slope and check accessibility compliance.
RC Time Constant Calculator
Calculate the RC time constant and charging curves.
Rebar Weight Calculator
Calculate the weight of reinforcing bar.
Refrigerant Line Charge Calculator
Estimate extra refrigerant for long line sets.
Resistor Color Code Calculator
Calculate resistance from color bands.
Retaining Wall Calculator
Estimate lateral earth pressure on a retaining wall.
Roofing Calculator
Calculate roof area and material from footprint and pitch.
Roof Panel Fit Calculator
Estimate how many solar panels fit on a roof.
Project Schedule Calculator
Estimate project duration from tasks and resources.
Section Modulus Calculator
Calculate section modulus for a rectangular section.
SEER Savings Calculator
Estimate AC energy savings from upgrading SEER rating.
Service Load Calculator
Estimate a dwelling's electrical service size.
Cable Signal Loss Calculator
Calculate signal attenuation over a coaxial cable run.
Soil Compaction Calculator
Calculate compacted vs loose soil volume.
Solar Power Calculator
Estimate daily energy from a solar array.
Commercial Solar Calculator
Estimate commercial solar size, output and cost.
Solar + Battery Calculator
Size solar and battery for self-consumption.
Solar ROI Calculator
Calculate payback and savings for a solar installation.
Solar System Sizing Calculator
Size a solar array to offset your energy use.
Solar Panel Tilt Calculator
Find the optimal fixed tilt angle for your latitude.
Specific Gravity Calculator
Calculate specific gravity from density.
Square Footage Calculator
Calculate area in square feet and metres.
Stair Calculator
Calculate riser height and tread depth for a staircase.
Steel Weight Calculator
Calculate the weight of a steel section by length.
Structural Load Calculator
Total dead, live and snow loads on a structure.
Structural Utilization Calculator
Check load utilization against member capacity.
Sugar Concentration (Brix) Calculator
Convert between Brix, specific gravity and sugar content.
Peak Sun Hours Calculator
Convert solar irradiance to peak sun hours.
Shadow Length Calculator
Calculate shadow length from object height and sun angle.
Tankless Water Heater Sizing
Size a tankless heater from flow and temperature rise.
Three-Phase Power Calculator
Calculate three-phase power, current or voltage.
Tile Calculator
Calculate tiles needed for a surface with waste.
Transformer Calculator
Calculate transformer voltage, current, or turns ratio.
Transformer Sizing Calculator
Size a transformer (kVA) for a load.
Voltage Drop Calculator
Calculate voltage drop in a copper wire run.
Advanced Voltage Drop Calculator
Voltage drop with conductor material and phase selection.
Water Pipe Flow Calculator
Estimate flow rate through a pipe from velocity and size.
Wire Gauge Calculator
Calculate wire resistance and current capacity by AWG.
Wire Size Calculator
Recommend a minimum wire gauge for a given current.
Process Yield Calculator
Calculate process yield and waste percentage.
How to choose the right Engineering tool
- Sizing beams, loads, or structures? Start with the civil and structural tools.
- Circuits, resistance, or power? Use the electrical calculators.
- Forces, stress, or motion in parts? The mechanical tools cover those.
- Confirm your units match the formula; mixing metric and imperial is the most common slip.
Who these tools are for
Used by engineering students and practising engineers for quick checks and first-pass estimates.
Need Help Solving a Problem?
Our AI Math Solver handles any math problem, just type it in plain English and get instant step-by-step solutions.
Explore Other Categories
Popular tools from our other scientific categories
Absolute Value Calculator
Calculate the absolute value of any number. Use this free calculator for fast, accurate answers, complete with the formula and a worked example.
AC to DC Converter Calculator
Convert AC voltage to DC voltage for different rectifier configurations. Free online calculator with instant, step-by-step results.
Acid-Base Titration Calculator
Calculate concentration from titration data. Get quick, accurate results with this free online calculator, including formulas and worked examples.
Amortization Schedule Calculator - Free Online
Free Generate a complete amortization schedule. Step-by-step solutions and formulas included. Free, accurate results with step-by-step explanations.
Average Cost Basis Calculator - Free Online
Free Calculate average cost per share. Step-by-step solutions and formulas included. Fast, accurate, and free, with formula and example.
1031 Exchange Calculator - Free Online
Free Calculate tax deferral in a 1031 exchange. Step-by-step solutions and formulas included. Fast, accurate, and free, with formula and example.
A1C Calculator - Free Online
Free Convert between A1C percentage and estimated average glucose. Step-by-step solutions and formulas included. Simple, fast, and free.
Batting Average Calculator
Calculate batting average in baseball/cricket. Free calculator with instant calculations, the underlying formula, and an easy-to-follow example.
Air Density Calculator
Calculate air density from temperature and pressure using the ideal gas law. Fast, accurate, and free, with formula and example.
Age Calculator
Calculate exact age in years, months, and days. Use this free calculator for fast, accurate answers, complete with the formula and a worked example.
Acceleration Converter
Convert between acceleration units. Get quick, accurate results with this free online converter, including formulas and worked examples.
Circle Area Calculator
Calculate the area and circumference of a circle. Free online calculator with instant results, step-by-step explanations, and a clear worked example.
Angle Between Two Lines Calculator
Calculate the angle between two lines given their slopes. Free calculator with instant calculations, the underlying formula, and an easy-to-follow example.
Apache Log Parser, Free Online Developer Tool
Parse Apache/NGINX combined access log lines into IP, time, request, status and size fields. Get instant results, the formula, and a clear example.
Add Text to Beginning, Free Online Text Tool
Add custom text to the beginning of every line in your text instantly. Get instant results, the formula, and a clear example.
Accessible Color Pair Finder
Check if a text/background pair meets WCAG and suggest a fix. Free tool with instant calculations, the underlying formula, and an easy-to-follow example.