# Developer & Tech Calculators - **URL:** https://codeasystem.com/calculators/developer/ - **Markdown index:** https://codeasystem.com/calculators/developer/index.md - **Calculators in this category:** 37 Developer calculators and tools for JSON, Base64, JWT, UUID, hashing, subnetting, uptime SLAs, cloud and LLM token costs. Focus areas: Encoding, security, networking, cloud and AI cost tools. ## All calculators - [Subnet & CIDR Calculator](https://codeasystem.com/calculators/developer/subnet-cidr-calculator.md); Turn an IPv4 address and CIDR prefix into network address, broadcast, usable host range, host count and wildcard mask. - [IP Address Format Converter](https://codeasystem.com/calculators/developer/ip-converter.md); Convert an IPv4 dotted-quad address between binary, hexadecimal, octal and 32-bit integer representations instantly. - [Port Number Lookup](https://codeasystem.com/calculators/developer/port-number-lookup.md); Identify which well-known service listens on a TCP/UDP port number, drawn from a static table of common assignments. - [MIME Type Lookup](https://codeasystem.com/calculators/developer/mime-type-lookup.md); Look up the Content-Type MIME type for a file extension, with an honest fallback for extensions without a standard mapping. - [Chmod Calculator](https://codeasystem.com/calculators/developer/chmod-calculator.md); Convert Unix file permissions between symbolic (rw-r--r--) and octal (644) notation with a per-class numeric breakdown. - [Download Time Calculator](https://codeasystem.com/calculators/developer/download-time-calculator.md); Estimate how long a file transfer takes at a given connection speed, with bits versus bytes handled correctly. - [API Pagination Calculator](https://codeasystem.com/calculators/developer/api-pagination-calculator.md); Compute page count, offset and item placement for paginated APIs; including honest handling of pages beyond the range. - [Storage Growth Calculator](https://codeasystem.com/calculators/developer/storage-growth-calculator.md); Project data volume after months of compound growth, with added-capacity figures and optional monthly cost impact. - [Uptime SLA Calculator](https://codeasystem.com/calculators/developer/uptime-sla-calculator.md); Translate an availability percentage into the exact downtime budget per day, 30-day month and year, humanized as clock time. - [Error Budget Calculator](https://codeasystem.com/calculators/developer/error-budget-calculator.md); Track how much of your SLO-derived error budget remains after recorded downtime, with a healthy-or-breached status. - [SRE Burn Rate Calculator](https://codeasystem.com/calculators/developer/sre-burn-rate-calculator.md); Compute how fast you are consuming error budget relative to plan, benchmarked against Google SRE fast-burn conventions. - [AWS EC2 Cost Calculator](https://codeasystem.com/calculators/developer/aws-ec2-cost-calculator.md); Estimate hourly, monthly and yearly EC2 on-demand cost for common us-east-1 instance types from a static snapshot price table. - [AWS S3 Cost Calculator](https://codeasystem.com/calculators/developer/aws-s3-cost-calculator.md); Estimate monthly S3 spend from storage volume, PUT/GET request counts and internet egress using snapshot tier pricing. - [LLM Token Counter](https://codeasystem.com/calculators/developer/llm-token-counter.md); Estimate how many tokens a piece of text consumes using character-based and word-based heuristics, plus an optional cost line. - [LLM API Cost Calculator](https://codeasystem.com/calculators/developer/llm-api-cost-calculator.md); Project monthly LLM API spend from per-call token usage, input/output pricing and call volume across your traffic mix. - [Context Window Calculator](https://codeasystem.com/calculators/developer/context-window-calculator.md); Check whether your system prompt, conversation history and reserved response fit inside a model’s context window. - [RAG Chunking Calculator](https://codeasystem.com/calculators/developer/rag-chunking-calculator.md); Work out how many chunks an overlapping-window chunking strategy produces, plus stored-token overhead and embedding cost. - [Embedding Storage Calculator](https://codeasystem.com/calculators/developer/embedding-storage-calculator.md); Size the memory footprint of a vector collection from count, dimensions and precision, including index overhead and RAM guidance. - [GPU Memory Calculator](https://codeasystem.com/calculators/developer/gpu-memory-calculator.md); Estimate GPU memory for running a model from parameter count, precision, batch size and KV cache allowance, with fit checks. - [Model Size Calculator](https://codeasystem.com/calculators/developer/model-size-calculator.md); Compute on-disk model weight size in decimal GB and binary GiB, plus download time over a 100 Mbps link. - [Concurrency & Throughput Calculator](https://codeasystem.com/calculators/developer/concurrency-throughput-calculator.md); Apply Little's law to solve the missing variable among arrival rate, latency and concurrent requests, with capacity guidance. - [Rate Limit Planner](https://codeasystem.com/calculators/developer/rate-limit-calculator.md); Convert an API quota into a safe sustained requests-per-second budget with pacing intervals and burst headroom. - [JSON Formatter & Validator](https://codeasystem.com/calculators/developer/json-formatter-validator.md); Validate JSON and reformat it with pretty indentation or minify it to a single compact line, with precise parse-error positions. - [Base64 Encoder & Decoder](https://codeasystem.com/calculators/developer/base64-encoder-decoder.md); Convert text to Base64 and back with full UTF-8 support; multilingual characters and emoji survive every round trip. - [URL Encoder & Decoder](https://codeasystem.com/calculators/developer/url-encoder-decoder.md); Percent-encode query-string components or whole URLs, and decode escaped strings back; malformed escapes are caught cleanly. - [HTML Entity Escaper & Unescaper](https://codeasystem.com/calculators/developer/html-entity-escaper.md); Escape the five HTML-critical characters (& < > " ') or unescape named, decimal and hexadecimal entities back to plain text. - [JWT Decoder](https://codeasystem.com/calculators/developer/jwt-decoder.md); Decode JWT header and payload claims with base64url-safe parsing, plus live expiry analysis against the current clock. - [UUID v4 Generator](https://codeasystem.com/calculators/developer/uuid-generator.md); Generate one to fifty random UUID version-4 identifiers using crypto.randomUUID with a documented RFC 4122 fallback. - [ULID Generator](https://codeasystem.com/calculators/developer/ulid-generator.md); Generate lexicographically sortable ULIDs; Crockford base32 timestamps plus 80 bits of monotonic randomness per the spec. - [Secure Password Generator](https://codeasystem.com/calculators/developer/password-generator.md); Build random passwords from selectable character classes with guaranteed coverage, ambiguity filtering and entropy estimates. - [Password Strength Calculator](https://codeasystem.com/calculators/developer/password-strength-calculator.md); Estimate password entropy from detected character classes and translate it into average offline crack time at your attack-speed assumption. - [SHA Hash Generator](https://codeasystem.com/calculators/developer/hash-generator.md); Compute SHA-1, SHA-256, SHA-384 and SHA-512 digests of any text at once using the browser’s native WebCrypto engine. - [HMAC Generator](https://codeasystem.com/calculators/developer/hmac-generator.md); Compute keyed HMAC-SHA-256/384/512 signatures for API requests and webhook verification using native WebCrypto. - [Unix Timestamp Converter](https://codeasystem.com/calculators/developer/timestamp-converter.md); Convert Unix seconds, milliseconds or ISO 8601 strings into every other format automatically, with relative-time context included. - [Cron Expression Parser](https://codeasystem.com/calculators/developer/cron-parser.md); Translate five-field cron expressions into plain English, validate every field range and list the next scheduled run times. - [Regex Tester](https://codeasystem.com/calculators/developer/regex-tester.md); Test regular expressions against sample text with live match counts, highlighted matches and capture-group breakdowns. - [Case Converter](https://codeasystem.com/calculators/developer/case-converter.md); Convert any text into camelCase, snake_case, kebab-case, PascalCase, CONSTANT_CASE and four more conventions simultaneously. Each link above points to the full Markdown reference for that calculator (inputs, formula, worked example, FAQs). The interactive HTML version lives at the same path without the `.md` suffix. --- Last updated: 2026-08-23 · [Section overview](https://codeasystem.com/calculators/index.md)