# All online calculators

- Numerical integration
To calculate definite integral by the rectangle method, trapezoid method, Simpson method or other Newton-Cotes quadrature methods.

- Ohm's law
This calculator determines current by voltage and resistance using ohm law

- Old Russian (Byzantine) system of chronology
Old Russian calendar - years since world creation

- Old Russian money
Converts old Russian monetary units into more common rubles and kopecks. Created by user's request.

- One-variable function graph
This online calculator plots one-variable function graph given function formula and range of variable

- Orthodox Easter date calculator
Using a modification of the Gauss algorithm to calculate Orthodox Easter date

- Oval Tank Volume Calculator
Find the volume of oval tanks in cubic inches and gallons.

- p-t Graph Analysis
This online calculator analyses position vs time table, which is often used to describe 1-D kinematics motion.

- P-value
This online calculator calculates p-value for one sided and two sided tests given the z-score

- Paired Sample t-Test
This online calculator performs t-Test for the Significance of the Difference between the Means of Two Correlated Samples

- Palette generator
This calculator generates palette of colors from starting color to ending color, using maximum diversity, "rainbow" style.

- Pangram checker
This online calculator can check if a phrase is a pangram.

- Parallel and perpendicular lines on a plane
This online calculator checks lines' slopes to see if they are parallel or perpendicular

- PATHFINDER cipher checker
This online calculator decrypts digits encrypted by PATHFINDER type of cipher.

- PBX channel number calculation
Calculates number of PBX telecommunications channels for given traffic load using Erlang B and Engset algorithms

- Pearson correlation coefficient
The calculation of the correlation coefficient of two random variables

- Peptide dissolution calculator
Peptides dissolution calculator

- Peptides dissolution calculator.
Peptides dissolution calculator.

- Percentage
This online calculator gives the percentage of the value. It also calculates the percentage of the sum (e.g. the income tax of the net salary) and the percentage of the difference (e.g. VAT of the gross amount).

- Petroleum product density
Petroleum product density conversion, according to GOST 3900-85