Online Toolbox: converters and calculators

Math

• Pocket calculator with history function and keyboard entry
• online regression calculator, find the equation/curve that fits best your data points.
• Line chart: online data visualization, plot your measurement data.
• https://www.desmos.com/calculator, online function plotter.
• RPN calculator
• Greg Hewgill's HP-15c calculator (local copy), powerful RPN calculator
• Prime numbers
• Number base converter (hex/bin/dec and other radix values) for numbers of arbitrary size
• Euclidean algorithm, Greatest Common Divisor (GCD), Highest Common Factor (HCF) as well as Least Common Multiple (LCM)
• Generic arbitrary precision number base converter

Networking

• IP/network address calculator,
  Zip file to download this calculator: ip_address_calculator.zip
  The calculator is as well available at https://guidosocher.neocities.org/ip_address_calculator/
• checkip: Show my IP
• Show the javascript navigator-object of your web-browser (user agent and other data)
• ANSI SS7 SCP converter, SCP=signaling point code

Electronic

• Calculators for electronic circuit design
• Resistor colors and Capacitor codes
• Conversion table: American Wire Gauge [AWG] and metric wire standards

Sound

• Decibel (dB) calculator for sound
• Tone generator, sine - square - sawtooth - triangle, use the sound card of your computer as a tone generator

Unit converter

• Units conversion
• cm to inch conversion with fractions

Encoding

• Javascript based text encryption/decryption using the blowfish cipher, you can use this to encrypt emails.
• Unicode (UTF-8) to HTML entity converter
• URL decoder / URL encoder
• Base64 http basic authorization encoder
• HEX color code calculator
• Image base64 encoder for html in-line images
• iso-8859-1 to HTML entity conversion: Convert accents and special characters into html entities for use in html code
• Web based one time passcode generator, edit and save on your device (e.g your phone), works with: symantec vip access, verisign, google authenticator, OATH-TOTP app, microsoft MFA, Amazon, ...
• Web bassed one time passcode generator for multiple tokens, edit and save on your device (e.g your phone), works with: symantec vip access, verisign, google authenticator, OATH-TOTP app, microsoft MFA, Amazon, ...
• Oneline one time passcode generator (symantec vip access, verisign, google authenticator, device independent), a copy is available at https://guidosocher.neocities.org/hmac-otp-generator/.

Time and date:

• Calendar, month view
• Calendar, year view
• A time difference calculator
• Calculate Time until Date
• A clock
• Stopwatch with log function

Misc:

• Luhn check digit calculator, credit card check digit, imei check digit
• Two letter abbreviations for states in USA and Canada
• International Spelling Alphabet
• show browser screen sizes, show javascript window and screen dimensions
• Commonly used special characters (copy/paste from here if your keyboard does not have them):
  Á À á à â É È é è ê î Ò ò ô Ù ù û Ç ç ß ä Ä ö Ö ü Ü
• Using the caps-lock key for something useful
• Mini tutorial: Learn javascript and html forms
• Mini tutorial: Learn javascript and html buttons

Older versions

• IP/network address calculator
• RPN Calculator: rpnjcal
• A simple calculator
• Simple number base converter (max 32bit numbers)
• Pocket calculator with keyboard entry