Health
Calculate cumulative sleep debt across the last 7 to 14 nights and generate a gradual recovery plan
sleep-debt-calculatorFormat Conversion
Convert text to and from binary bit strings using ASCII (7-bit) or UTF-8 (8-bit) encoding
text-to-binaryFormat Conversion
Convert text to/from Unicode escape sequences (\uXXXX / \u{XXXXXX}) and apply Unicode normalization (NFC/NFD/NFKC/NFKD)
unicode-escape-converterFormat Conversion
Escape and unescape XML special characters (& < > " ') with optional numeric references, slash escaping, and CDATA wrapping
xml-escapeDevelopment
Complete HTTP status code reference (1xx–5xx) with semantics, typical scenarios, and retry advice in a filterable comparison table
http-status-referenceNetwork
Look up the manufacturer of a MAC address from the IEEE OUI database, or reverse-search a company name to list all its OUI blocks — fully offline
mac-oui-vendor-lookupMath & Numbers
Solve C1V1=C2V2 dilutions, stock-to-working recipes, and simple serial dilution plans
molarity-dilution-c1v1-calcDesign
Convert bidirectionally between HEX, RGB, HSL, OKLCH and Display-P3 using CSS Color 4 math, with gamut checks and out-of-gamut clipping suggestions
oklch-color-converterDevelopment
Preview Google SERP (pixel-accurate desktop & mobile truncation), X (Twitter) Card, and OpenGraph card side by side, with pre-launch SEO diagnostics
serp-social-preview-studioDevelopment
Parse EXPLAIN / EXPLAIN ANALYZE output (PostgreSQL/MySQL/SQLite) into a cost tree, flag estimated-vs-actual row divergence, and suggest indexes
sql-explain-plan-visualizerHealth
Convert swim benchmark times into 25m, 50m, and 100m pacing and generate CSS-style threshold intervals
swimming-pace-interval-builderHealth
Estimate BMR, TDEE, ideal weight, and macro splits for weight loss, maintenance, or muscle gain
tdee-bmr-body-comp-calculator