The SI-system, unit converters, physical constants, drawing scales and more

Acceleration Units Converter

Convert between common units of accelerations

Acceleration of Gravity and Newton's Second Law

Acceleration of gravity and Newton's Second Law - SI and Imperial units

Air Properties

Density, specific heat, thermal conductivity, expansion coefficient, kinematic viscosity and Prandtl's number - for air temperatures ranging from -150 oC to 400 oC

Angle Converter

Convert between angle units

British Imperial System

A principal system of units

Circles - Circumferences and Areas

Area and circumferences of circles with diameters in inches

Conversion Chart - from Inches to mm

Convert fractional and/or decimal inches to metric mm - and vice versa

Convert Gallons of Water to Pounds

and vice versa

Decimal System Prefixes

Prefix Names of Multiples and Submultiples of Units

Density, Specific Weight and Specific Gravity

An introduction to density, specific weight and specific gravity - formulas with examples

Drawing Scales

Commonly used scales for blueprint drawings


Usefulnes of a process

Electromagnetic Spectrum

Electromagnetic wavelengths and frequencies

Elements of the Periodic System

The elements of the periodic system with names, symbols, atomic numbers and weights

Empirical Equations

Empirical equations or formulas


Mechanical, thermal, electrostatic, phase and chemical equilibrium

Exponents - Powers and Roots

Fractional and integer exponents laws

Flow Units Converter

Convert between volume flow units - gpm, liter/sec, cfm, m3/h - an online flow unit calculator

Inches - Decimal Equivalents

Decimal equivalents of eights, sixteenths, thirty-seconds and sixty-fourths of an inch

Inches - Fraction Decimal Equivalents

Inches - fractional decimal equivalents

Inches to feet, yards and meters - Conversion Chart

Convert from inches to feet, yards and meters

Length Units Converter

Convert between common length units like meters, feet, inches, nautical miles and more


Rules of logarithms - log10 and loge for numbers ranging 1 to 1000

Mass and Weight

Mass and Weight - the difference

Mixtures, Solutions and Suspensions

The difference between mixtures, solutions and suspensions

Mole and Avagadro's Number

The mole is the SI base unit for amount of substance

Moment of Inertia

Moment of Inertia (Mass Moment of Inertia) depends on the mass of the object, its shape and its relative point of rotation - Radius of Gyration

Natural Trigonometric Functions

Sine, Cosine and Tangent - Natural Trigonometric Functions

Online Fuel Equivalents Calculator

Online calculator to compute the fuels equivalents - oil and gas

Online Units Conversion Calculator

Convert Energy, Pressure, Volume, Density, Specific Volume, Specific Heat (Entropy), Enthalpy, Thermal Conductivity, Viscosity (absolute) or Coefficient of Heat Transfer units

Ounces and Pounds converted to Grams

Converting ounces (ozs.) and pounds (lbs.) to grams (g)

Parts per million - ppm

ppm - parts per million - is commonly used as a unit of concentration

Periodic Table of Elements

The periodic table of the elements with atomic numbers

Physical Constants

Physical constants - SI Units


Introduction to pressure - psi and Pa - online pressure units converter

Pressure Units - Online Converter

Convert between pressure units like Pa,  bar, atmosphere, pound square feet, psi and more

Pressure to Head Unit Converter

Convert between pressure and head units - lb/in2, atm, inches mercury, bars, Pa and more ..

Properties and State

Concept of properties and state

Pumps, Fans and Turbines - Horsepower

British Horse Power in pumps, fans and turbines - and how to convert to other commonly used units


The radian - a unit of angle measure - angular velocity

Ratio and Proportion

The ratio and proportion between quantities

Real Numbers Algebra

Real numbers algebra - commutative law for addition, associative law for addition and more

SI System

An introduction to the SI-system

Solar System Constants

Sun, Earth and Moon constants

Solids - Volume and Surface

Volume and surface of solids like rectangular prism, cylinder, pyramid, cone and sphere - online calculator

Some Measuring Units

Some commonly used measuring units - gross, dozen, quire, sheets ..

Specific Heat - Online Converter

Online specific heat converter with the most commonly used units


Introduction to temperature - including Celsius, Fahrenheit, Kelvin and Rankine definitions - an online temperature converter

U.S. Gallons to U.K. Gallons, Cubic Feet and Cubic Meters - Converting Chart

Convert between U.S. liquid Gallons, U.K. liquid Gallons, Cubic Feet and Cubic Meters

USCS - United States Customary System Units

United States Customary System Units or Imperial Units

Unit Converter with the most commonly used Units

Common converting units for Acceleration, Area, Density, Energy, Energy per unit mass, Force, Heat flow rate, Heat flux, Heat generation per unit volume and many more

Vector Addition

Online vector calculator - add vectors with different magnitude and direction

Velocity Units Converter

Convert between common velocity and speed units - online converter

Volume Units Converter

Convert between common volume units like cubic meters, cubic feet, cubic inches and more

Water Content in Foods and other Products

Products and water content before and after drying - common material like foods, cork, grain, soap, peat, wood and more

Water Pressure and Head

Pressure in pounds per square inch (psi) versus head in feet of water (fth2o)

pH Definition

Introduction to pH

Search the Engineering ToolBox

- "Search is the most efficient way to navigate the Engineering ToolBox!"

Engineering ToolBox - SketchUp Extension - Online 3D modeling!

3D Engineering ToolBox Extension to SketchUp - add parametric components to your SketchUp model

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your SketchUp model with the Engineering ToolBox - SketchUp Extension/Plugin - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

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