All online calculators

  • Gregorian calendar. Julian calendar. The calendar eras.

    The calculator convers julian calendar date to gregorian calendar date taking in account the calendar era.

  • H264 Maximum References Frames

    H264 Maximum References Frames

  • Hack

    Hack the three-digit code

  • Hartley's formula

    Hartley's formula to determine the amount of information contained in a message with length n.

  • Heat Index

    This calculator calculates heat index (apparent temperature), which is used by US meteorologists to determine the human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade.

  • Height in old Russian system of measures

    This calculator computes height expressed in old Russian measure system units: arshins and vershoks

  • Hill cipher

    This calculator uses Hill cipher to encrypt/decrypt a block of text

  • Hip roof calculator

    This calculator will help you estimate hip roof parameters, including rafters and roof area

  • Histogram

    Histogram generation according to input data. The number of groups is determined by the Sturgess formula, other formulas or set manually

  • Histogram group number

    Sturges formula and other methods of determining the number of groups in histogram generation

  • How many circles of radius r fit in bigger circle of radius R

    This calculator estimates how many circles of radius r can be placed inside another circle of radius R.

  • How many days are there between two dates?

    This is simple day calculator which determines number of days between two dates.

  • How many hours between two days

    This online calculator helps you to calculate how many hours (and minutes) between two week days, i.e., Friday at 7 a.m. until Sunday at 9 p.m.

  • How many months are there between two dates?

    This online calculator calculates how many months are there between two dates.

  • How many weeks are between two dates

    This calculator determines number of weeks between two given dates

  • How many workdays between two dates?

    The calculator evaluates number of working days and holidays for a period of time. The calculator based on the U.S. federal holidays table recognised in most states.

  • HTML table to JSON array

    Th calculator converts the html table code to JSON array with optional data transpose and compression. It also visualizes numeric data on chart.

  • Huffman coding

    This online calculator generates Huffman coding based on a set of symbols and their probabilities

  • Humidification loads

    This online calculator answers question "how to choose" humidifier, by calculating humidification requirements given initial and target relative humidity and building parameters

  • Humindex

    This calculator calculates Humindex, index used by Canadian meteorologists to describe how hot the weather feels to the average person, by combining the effect of heat and humidity.