DigitHelm

Computer Science calculators

These calculators cover how computers represent and move data: binary arithmetic, bitwise operations, two's complement and IEEE 754 floating point, checksums and error-correcting codes, hashing and RSA, classic algorithms (binary search trees, Huffman coding, knapsack), IP subnets and bandwidth, the z-transform, and display and color tools such as PPI, RGB to HEX conversion and contrast checking.

20 tools · Updated October 21, 2026

Showing 20 tools
Bandwidth CalculatorNetworks, displays and color4 GB at 100 Mbps, 6% overhead5 min 40 s
Binary Arithmetic CalculatorBinary and number representation1011 + 110 in binary10001 (17 in decimal)
Binary Search Tree CalculatorAlgorithms, compression and signalsInsert 50, 30, 70, 20, 40, 60, 80Height 2, balanced
Bitwise CalculatorBinary and number representation0b1100 AND 0b1010 (8-bit)8 (0x08)
Color Contrast CheckerNetworks, displays and color#595959 text on #FFFFFF7.00:1, AAA
CRC CalculatorError detection, hashing and cryptographyCRC-32 of “123456789”0xCBF43926
Floating Point ConverterBinary and number representation0.1 as a 32-bit float0x3DCCCCCD
Hamming Code CalculatorError detection, hashing and cryptographyHamming(7,4) code for 10110110011
Hash GeneratorError detection, hashing and cryptographyMD5 of “Hello, world”bc6e6f16b8a077ef…
Huffman Coding CalculatorAlgorithms, compression and signals“this is an example of a huffman tree”135 bits, 53% smaller
Image Print Size CalculatorMore computer science tools6,000 × 4,000 px at 300 PPI20.0 × 13.3 in
IP Subnet CalculatorNetworks, displays and colorNetwork for 192.168.1.130/26192.168.1.128/26
Knapsack CalculatorAlgorithms, compression and signals6 camping items, capacity 10Best value 115
Number Base ArithmeticBinary and number representation1A × B in base 1611E (286 in decimal)
PPI CalculatorNetworks, displays and color2,560 × 1,440 on a 27 in screen108.8 PPI
RGB to HEX Color ConverterNetworks, displays and color#3A7BD5 to RGBrgb(58, 123, 213)
RSA CalculatorError detection, hashing and cryptographyRSA with p = 61, q = 53, e = 17d = 2753
Two's Complement CalculatorBinary and number representation−42 in 8-bit two’s complement1101 0110
Uptime and SLA CalculatorMore computer science toolsDowntime allowed at 99.9% uptime8 h 46 min a year
Z-Transform CalculatorAlgorithms, compression and signalsH(z) = 1 ÷ (1 − 0.5z⁻¹)Pole at 0.5, stable

Which one do I need?

I want to add or subtract binary numbersBinary Arithmetic CalculatorI need AND, OR, XOR or bit shifts on two numbersBitwise CalculatorI want to see how a negative number is stored in binaryTwo's Complement CalculatorI want to see why 0.1 cannot be stored exactly in binaryFloating Point ConverterI need the network address, broadcast address and host range for a CIDR blockIP Subnet CalculatorI want to know how long a file will take to download at a given speedBandwidth CalculatorI want a SHA-256 hash of some textHash GeneratorI want to check if my text and background colors meet WCAG contrastColor Contrast Checker

How numbers are stored

Computers store integers in fixed-width binary. Negative integers almost always use two's complement, where you invert the bits and add one; this lets the same addition circuit handle positive and negative values. An 8-bit signed integer therefore runs from −128 to 127, and adding 1 to 127 wraps around to −128. The Two's Complement and Bitwise calculators make these patterns visible.

Fractions use IEEE 754 floating point, which stores a sign, an exponent and a significand. A double has 53 bits of precision, about 15 to 17 decimal digits, and many decimal fractions such as 0.1 have no exact binary form. The Floating Point Converter shows the exact stored bits and the tiny error they carry.

Detecting errors and protecting data

Checksums and error-correcting codes protect data in transit and storage. A CRC detects accidental corruption such as burst errors on a network link, while a Hamming code adds parity bits that can locate and correct a single flipped bit. Neither is designed to resist deliberate tampering.

Cryptographic hashes such as SHA-256 are designed so that finding two inputs with the same output is infeasible, which makes them suitable for integrity checks and digital signatures. SHA-1 is no longer considered collision-resistant and should not be used for security. The RSA Calculator walks through key generation and encryption with small numbers to show the math, but real keys need sizes of 2048 bits or more.

Networks, displays and accessibility

A CIDR prefix such as /24 says how many leading bits identify the network. A /24 has 256 addresses, of which 254 are usable by hosts in a traditional subnet after reserving the network and broadcast addresses. The IP Subnet Calculator gives the range, mask and host count for any prefix.

On the display side, the PPI Calculator works out pixel density from resolution and screen size, the RGB to HEX Converter translates color formats, and the Color Contrast Checker tests text against WCAG guidelines, which ask for a contrast ratio of at least 4.5:1 for normal body text at level AA.

Questions people ask

Neither 0.1 nor 0.2 can be represented exactly in binary floating point, so each is stored as the nearest available value. Their sum is very slightly off from the stored value for 0.3. Comparing with a small tolerance, or using decimal types for money, avoids the problem.

Other science topics