Developer Tools & Calculators
Speed up your development workflow with free online tools for encoding, conversion, networking, text manipulation, and AI cost estimation. Convert between number bases, encode Base64, calculate IP subnets, generate passwords, estimate LLM API costs, and more — all running client-side with no data sent to any server.
LLM Pricing Calculator — GPT-5, Claude, Gemini & 160+ AI Models
Paste your prompt, pick a model, see the exact cost per request, per day, and per month. Live token counting, 2026-verified pricing, embedded playground, 15-strategy cost optimization guide. Covers GPT-5 family, Claude Opus 4.6, Gemini 3.1, Llama 4, DeepSeek V3, Mistral Large 3, Grok 4, and every other major LLM.
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Encoding & Conversion
ASCII, Base64, text case, timestamps, and color conversion tools.
ASCII Converter
Convert between ASCII text, decimal, hex, and binary values.
Base64 Encoder
Encode and decode Base64 strings for data embedding.
Text Case Converter
Convert text to uppercase, lowercase, title case, or camelCase.
Unix Timestamp Converter
Convert Unix timestamps to human-readable dates and vice versa.
Color Converter
Convert between HEX, RGB, HSL, and CMYK color formats.
Number Systems
Hex, binary, and number base conversion and arithmetic.
Hex Calculator
Perform arithmetic and conversions in hexadecimal.
Binary Calculator
Perform arithmetic and conversions in binary.
Number Base Converter
Convert numbers between any base from 2 to 36.
Networking & Web
IP subnets, data storage, pixel-to-em, and CSS tools.
IP Subnet Calculator
Calculate network address, host range, and broadcast from CIDR.
Data Storage Converter
Convert between bytes, KB, MB, GB, TB, and PB.
Pixel to Em Calculator
Convert pixel values to em or rem units for responsive CSS.
Text & Security
Word counting and password generation tools.
Frequently Asked Questions
How do I encode or decode Base64?
Paste your text or Base64 string into the Base64 encoder tool and click encode or decode. Base64 encoding converts binary data into ASCII characters, commonly used for embedding images in HTML/CSS, sending email attachments, or passing data in URLs. The tool handles both standard and URL-safe Base64 variants.
How do I convert between number bases (hex, binary, decimal, octal)?
The number base converter lets you enter a value in any base (binary, octal, decimal, or hexadecimal) and instantly see it in all other bases. The hex calculator and binary calculator provide arithmetic operations within those specific bases. These tools are essential for debugging, working with memory addresses, and understanding low-level data.
How do I calculate IP subnets?
Enter an IP address and subnet mask (or CIDR notation like /24) into the IP subnet calculator. It shows the network address, broadcast address, usable host range, number of hosts, and wildcard mask. This is critical for network planning, VLAN configuration, and firewall rule setup.
How do I convert pixels to em or rem for CSS?
The pixel-to-em calculator converts pixel values to em or rem units based on the base font size (typically 16px). Enter the pixel value and base size to get the equivalent em value. Using relative units like em and rem makes your CSS responsive and accessible, scaling properly with user font size preferences.