Developer Tools Calculators
21 calculatorsPractical tools for developers and IT professionals: formatting, encoding, parsing, regex, API debugging, and AI/LLM cost estimation.
21 calculators available
Developer Utilities(12)↑ top
API Rate Limit & Cost Calculator
Estimate API cost and throttling risk from rate limits, burs…
Bandwidth Calculator
Calculate the network bandwidth you need for your users, act…
Bundle Size Impact Calculator
Estimate the real cost of an npm package: parsed, gzip, and …
Contrast Checker
Check the WCAG 2.x contrast ratio between two hex colors and…
Cron Expression Parser
Parse cron expressions and calculate the next run times usin…
IP Subnet Calculator
Calculate subnet ranges, broadcast addresses, usable hosts, …
JWT Decoder
Decode JWT tokens to inspect the header and payload instantl…
Password Generator
Generate cryptographically strong random passwords with conf…
Regex Tester
Test regular expressions against text live with match and re…
SQL Index Selectivity Calculator
Estimate index selectivity and query cost from cardinality. …
Timestamp Converter
Convert Unix timestamps to readable dates and back, supporti…
UUID Generator
Generate UUID v4 and v7 identifiers instantly in your browse…
Formatting & Encoding(5)↑ top
Base64 Encode / Decode
Encode text or binary data to Base64 or decode Base64 string…
Case Converter
Convert text between camelCase, PascalCase, snake_case, keba…
Color Converter
Convert colors between Hex, RGB, HSL, and HSV with a live pr…
JSON Formatter & Validator
Format, validate, and minify JSON data instantly. Supports p…
URL Encode / Decode
Encode or decode text with URL percent-encoding (RFC 3986). …
AI & LLM Tools(4)↑ top
Context Window Calculator
Compare context window sizes across GPT-6 Astra, GPT-5.6, Cl…
LLM API Cost Calculator
Calculate API costs for GPT-6 Astra, GPT-5.6, Claude Opus 5,…
Token Counter Calculator
Estimate token counts and API costs across GPT-6 Astra, GPT-…
Token Optimization Savings Calculator
Estimate LLM token optimization savings from prompt compress…
Frequently Asked Questions
- ❓ How do I format JSON for readability?
- ✅ Paste raw JSON into our JSON formatter and it will indent, sort, and validate the structure. It also flags syntax errors so you can catch malformed responses before shipping them.
- ❓ What is a UUID and how is it generated?
- ✅ A UUID (Universally Unique Identifier) is a 128-bit identifier used to tag records, sessions, and objects. Our UUID generator produces version 4 random UUIDs with a full 122 bits of randomness, so collisions are practically impossible.
- ❓ How do I estimate LLM API costs?
- ✅ Enter the token count, pricing per 1K input/output tokens, and expected traffic. The calculator accounts for the input/output price split and caching multipliers to project your monthly spend.