Technology Calculators
IP subnets, bandwidth, passwords, encoding and electronics tools.
- Binary and Hex ConverterType a whole number, say which base it is in and which base you want.
- Subnet CalculatorEnter an IPv4 address and the prefix length (the number after the slash, such as 24).
- Download Time CalculatorEnter the file size, your connection speed and how much of that speed you actually get.
- Data Storage ConverterEnter an amount of data, choose the unit it is in and the unit you want.
- Aspect Ratio CalculatorEnter the original width and height, then the new width or the new height you want.
- PX to REM ConverterEnter a size, choose the direction and the base font size.
- Ohm's Law CalculatorChoose which two values you know and type them in.
- Hex to RGB Color ConverterType a color as hex, rgb() or hsl().
- Voltage Drop CalculatorEnter the wire size, the length of the run, the current and the supply voltage.
- Resistor Color Code CalculatorChoose the number of bands and pick the colors, or switch to the other mode, type a resistance and get the bands.
- Base64 Encoder and DecoderChoose encode or decode and type your text.
- URL Encoder and DecoderChoose encode or decode, pick the style and type your text.
How these technology calculators work
These tools cover the arithmetic that comes up in networking, web design and electronics. The Subnet Calculator turns an IPv4 address and prefix into the network address, broadcast address and host range: a /24 has 256 addresses, of which 254 are usable hosts in the usual layout. The Download Time Calculator divides file size by connection speed. Remember that speeds are quoted in bits per second and files in bytes, a factor of 8, which is why a 100 Mbps connection moves at most about 12.5 megabytes per second.
The Ohm's Law and Voltage Drop calculators work from V = I × R and the resistance of the wire. The Resistor Color Code Calculator reads the bands on a resistor. The PX to REM Converter assumes the browser default of 16 pixels per rem unless you change the base size. Base64 turns every 3 bytes into 4 text characters, so the encoded text is about a third larger, and it is an encoding, not encryption. The Binary and Hex Converter and the Hex to RGB Color Converter handle number bases and color values.