Developer & Utility Calculators

Format, validate and beautify JSON. Pretty-print, minify and spot syntax errors in API responses.

Encode text to Base64 and decode back. Handles Unicode and URL-safe variants for developers and QA.

Generate v4 UUIDs. Generate one or many random identifiers for databases and APIs.

Decode JWT tokens (header and payload). Inspect claims and expiry without sending tokens to any server.

Generate MD5 and SHA hashes. Compare checksums and verify data integrity right in the browser.

Convert Unix timestamp to date and vice versa. Free online tool with instant results, formulas and worked examples.

Test regular expressions with live matching. Debug patterns with capture groups, flags and instant highlighting.

Convert between HEX, RGB, HSL. Handy for designers matching brand colors across tools.

Calculate width or height for a given aspect ratio.

Generate a QR code for any text or URL. Great for links, WiFi, contact cards and offline sharing.

Generate strong random passwords. Choose length and character sets for accounts, keys and Wi‑Fi.

Estimate password entropy and crack time. See how long attackers would need at various guess rates.

Estimate file size from dimensions. Free online tool with instant results, formulas and worked examples.

Time to transfer a file at a given bandwidth. Plan uploads, backups and video delivery over any connection.

Convert between KB, MB, GB, TB. Handles binary and decimal units used by OSes and cloud vendors.

Estimate monthly AI API costs across OpenAI, Anthropic, Google and open models by tokens and request volume.

Calculate OpenAI API spend for GPT-4o, GPT-4o mini, GPT-4 Turbo, o1 and GPT-3.5 by tokens and request volume.

Convert token counts and per-million-token prices into dollar cost per request, per day and per month.

Estimate ChatGPT API costs for building a chatbot — includes conversation history, system prompts and monthly volume.

Estimate monthly GitHub Actions spend by runner OS, workflow minutes, jobs and included free tier.

Calculate monthly API spend by requests, cost per 1,000 calls, data transfer and free tier.

Compare monthly cloud VM costs across AWS, Azure and GCP with storage, egress and reserved-instance discounts.