# All online calculators

- Digital image size in pixels and photo print size
This article is about relation between image size in pixels and photographic print size. First, it recommends photographic print size for given digital image dimensions in pixels. Second, it finds resulting pixels per inch value for printed digital image with known linear and pixel dimensions.

- Direct observation error analisys
Calculates error of direct measurements for given measured value series and confidence interval.

- Display aspect ratio and dimensions
This online calculator finds screen dimensions - height, width and area, given the diagonal value and aspect ratio.

- Distance across the surface vs distance through the Earth
This calculator calculates distance across the surface of the Earth and distance through the Earth for given two points, then compares them.

- Distance between two cities
Calculates the distance between the two cities. Uses the directory of geographical city coordinates for the calculation.

- Distance calculator
Calculates distance between two geographic coordinates using haversine formula.

- Distance through the Earth
This calculator calculates the distance from one point on the Earth to another point, going through the Earth, instead of going across the surface.

- Dollars to rubles and vice versa by Central Bank of Russia exchange rate
- Doppler Effect in sound
Calculation of frequency and wavelength change for a moving source

- Double exponential smoothing
Description and example of the double exponential smoothing

- Earth Radius by Latitude (WGS 84)
This online calculator calculates Earth radius at given latitude using WGS 84 reference ellipsoid

- Effective interest rate
- Ellipsoid
Calculates ellipsoid and spheroid volume and surface area.

- Email extractor
This online calculator parses emails from block of text using regular expression

- Energy measurement units
Energy unit converter (joules, kilowatt-hour, kilogram force per meter, horsepower per hour, kilocalories)

- Equilibrium moisture content
The calculator gives the wood equilibrium moisture content by given temperature and relative humidity.

- Estimated Mean of a Population
This online calculator allows you to estimate mean of a population using given sample

- Evaluating expressions
This online calculator substitutes a specific value for each variable, and performs the operations, evaluating the given expression.

- Exotic length units
Converter from exotic length units to meters

- Exponential Moving Average
Exponential Moving Average calculation by candles