


Financial Calculators 

Loan Calculator
This calculator takes any two of the three variables (Loan, Interest Rate, and Number of months) and gives the answer for the remaining one. The advanced version allows for different compounding and payment frequencies. Also, Canadian users will find this Canadian Mortgage Calculator rather handy as the interests default to compound semiannually.

Lease Calculator
Leasing a car? Confused about the money factor that car dealers always mention? We have a mathematical proof that relates money factor to the actual interest rate. The advanced version allows for different compounding and payment frequencies.

APR Calculator
So what is the difference between APR and the Interest Rate? This calculator gives a full definition of APR and helps you determine it for a given interest rate and points cost. The advanced version allows for different compounding and payment frequencies.

Currency Calculator
Updated daily, this calculator gives the exchange rates of more than 60 currencies and converts from one to another.


Engineering Design Aids 

Unit Conversion Calculator
Featuring more than 800 units in our database (and growing), we give the unit definition and SIdimensions in addition to converting from one unit to other units in the same family.

Fraction Calculator
Design engineers, ever wonder what the closest 32^{nd} number is for a decimal fraction? This calculator tells you where your decimal fraction stands on the 1/8, 1/16, 1/32, and 1/64 scales.

Gage Calculator
There are so many systems for gaging wires and sheets. This calculator allows you to convert back and forth between gages and the actual decimal numbers in different standards.

ORing Calculator
This calculator outputs the ORing inner diameter and the range of ORing crosssection diameters that will meet user prescribed limits on groove and bore diameters and ORing compression.

Spring Calculators
Frustrated by reading spring catalogs trying to figure out which spring gives you the right force or displacement? Maybe one of these 8 calculators can help you. More calculators will be added soon!

Hardness Approx. Converter
This calculator explains and interconverts comomonly used hardness scales, including Brinell, Knoop, Mohs, Rockwell, Shore, and Vickers.


Mechanical Formulas 

Beam Calculators
Featuring 11 calculators that output the displacement, rotation, force, moment, and shear for beams with different boundary conditions under various loadings.

SDOF Vibration
This calculator returns the natural frquencies, damping ratio, and the closedform solution for a SingleDegreeOfFreedom massspringdamper system.

Reynolds Number
This calculator quickly gives you the Reynolds Number for a flow over a plate or a flow in a pipe.

Venturi Flowmeter
This calculator outputs the flowrate through a venturi constriction for a given pressure drop.

Pipe Friction
Frustrated by using the Moody Chart to calculate pressure loss in pipes? This calculator does it for you and tells you the Reynolds number, pressure drop, and flow rate for a constant crosssection pipe.

Radiation
Ever wonder how much heat per second is radiated from your (bald) head to the dark night sky if you are standing in an open field? You can use this calculator to figure that out!

Laminar Flow Over Plate
Heat convection by forced laminar flow over an isothermal plate.

Stress Transforms
Remember Mohr's Circle? We provide calculators that execute the math behind Mohr's Circle for the cases of Plane Stress and Plane Strain.

Principal Stress
Need to find the principal stresses and their directions for a given input stress state? These calculators do the math for you for the case of Plane Stress and Plane Strain.

Elastic Constants
OK, we all remember that an isotropic material requires only 2 elastic constants to describe its material behavior. But which 2 constants to use? Youngs modulus, Poisson ratio, shear modulus, or bulk modulus? Don't sweat it anymore  this calculator allows you to convert from any 2 constants to all others in common use.

Failure Criteria
Remember how to apply von Mises and the Maximum Shear criteria to evaluate failure risk? How about Maximum Stress or Mohr's Theory? We encourage you to freshen up on the basics, but short of that here are 2 calculators for applying failure criteria to brittle and ductile materials.

Plate Calculators
Featuring 11 calculators that output the maximum displacement and stress for common plates with different boundary conditions under various loadings.

Stress Concentration
11 calculators are provided to calculate the stress concentration factor K for common features such as notches, holes, grooves, and shoulders.

Column Buckling
Critical Load Calculator computes the critical load, the boundary condition factor, and the effective length of a column; Structural Steel Column Calculator is designed specifically for structural steel columns to compute the allowable stress with respect to a given safety factor.

Composite Materials
3 calculators are provided to help determine the mechanical properties of the composite lamination with multiple layers. First, the equivalent material constants of a single layer along the principal directions are estimated. Then, the stiffness and compliance matrices of such a layer are constructed. Finally, the laminae are 'glued' together and the stiffness matrices A, B, and D of the laminate are built.

Saturated Steam Table
Temperature and pressure of saturated steam are closely related. When one of them is given, the other is determined. This calculator calculates the density, specific volume, internal energy, enthalpy, and entropy of saturated steam based on tabulated data using interpolation.


Mathematics 

