Twin Calculators, which combines two calculators into one, and the calculation result can be copied and pasted between the two calculators with one click.

The two calculators are displayed side by side in landscape mode, and vertically in portrait mode.

In addition to separate calculations for each calculator, the calculation result can also be copied and pasted with one click, and other calculations can be performed during the calculation process, which is convenient for comparison and recording of results during calculations.

Calculation results can be imported from one calculator to another with one click:

When the ">>" key is pressed, the calculation result of the calculator on the left will be entered at the end of the formula on the calculator on the right.

When the "<<" key is pressed, the calculation result of the calculator on the right is entered at the end of the formula of the calculator on the left.

Feet and Inches Calculator is an easy-to-use online calculator that is used to evaluate the addition, subtraction, multiplication, and division of two values in feet and inches, and allows you to efficiently perform mathematical operations on measurements expressed in feet and inches.

Roofing Calculator is a free roofing square footage calculator to determine your roof size and get the right amount of roofing shingles for your job.

Pythagorean Theorem Calculator could finds the unknown side length of a right triangle to quickly solve right triangle problems.

Percent To Fraction Calculator could help you to convert the given percentages into fractions.