# All online calculators

- Tips and tricks #5: How to show/hide input and output controls in a calculator
This article describes how to control visibility of input and output controls in a calculator

- Tips and tricks #6: How to make calculator with virtual keyboard
This article describes how to create calculator with virtual keyboard using SVG image

- Tips and tricks #7: How to make calculator with SVG image map
This article describes how to create calculator with image map using SVG image

- Tips and tricks #8: How to reuse existing calculator
This article describes process of reusing another calculator's logic (algorithm) in your calculator.

- Tips and tricks #9: Big numbers
How to use big number input and PCR library.

- Ton-kilometer. Conversion based on the cost of a kilometer
Calculation of a cost of ton-kilometer

- Torus
Volume and surface area of torus.

- Total square
This calculator calculates total square as sum of squares of entered rectangles

- Total time
- Total time
This calculator allows you to carry out the addition of the time - it displays the total, the average, minimum and maximum.

- Total volume
This calculator calculates total volume as sum of volumes of entered rectangular parallelepipeds.

- Tournament table
The calculator performs the participant placement with two following conditions: 1) Each participant must start from each starting position. 2) Each participant must encounter every other participant.

- Trapezoid - Shaped Throat Opening
Use this calculator to lay out a trapezoidal shaped throat cut-out. Enter the throat area from the PitCalc, your tank's diameter and dam height.

- Travel Duration
This online calculator computes travel duration given departure time and city and arrival time and city using time zones information

- Traveling Wave Relationship
The relationship of the wave frequency, wavelength and propagation velocity.

- Triangle angles for given triangle sides
This calculator computes triangle angles for given triangle sides using cosine law

- Trigonometric functions
This online calculator computes the values of elementary trigonometric functions, such as sin, cos, tg, ctg, sec, cosec for an angle, which can be set in degrees, radians, or grads.

- Triple exponential smoothing
Description and examples of triple exponential smoothing

- Two argument arc tangent
The calculator gives an angle between positive axis x and the ray to the given point from point 0. The result corresponds to atan2 function, implemented in many computer languages and math libraries.

- Two sample t-Test
The calculator to perform t-Test for the Significance of the Difference between the Means of Two Independent Samples