123calculus.com/en is a free calculator with a large collection of calculators in mathematics, physics, chemistry, converters, time & dates, finance and health.
For your math calculations, you may use our calculators in fractions, arithmetic, trigonometry, combinatorics, functions, equations, matrix and vector, sequences and series, complex numbers, geometry and statistics.
The physics section includes calculators in various fields like force, motion, pressure, optics, power, energy, electricity, thermodynamics, etc.
In the chemistry section you'll find calculators on electronic structure of atoms and molecules, physico-chemical calculators, chemical solutions and reactions, converters of units in chemistry, etc.
In the finance section, you can simulate financial products such as real estate credit, auto credit, savings.
Our website can also help you on calculations related to time and dates : working days, time zones, age, duration, conversion of time units, etc.
Finally, the website provides you with tools to convert units of length, area, volume, pressure, mass, speed, temperature, energy, storage memory, etc.
The calculation pages always include explanations about used methods and formulas. Sometimes, they also include the calculations step by step.
We are open to your questions and suggestions to improve the website and add new online calculators. You can use the contact form or a form at the bottom of each calculation page to send us your comments.