Free Cool Tools Online is a hand-crafted collection of 38 browser tools — each built with the care of a native app, not stamped from a template. Originals you won't easily find elsewhere — client-side cryptography, serious financial models, a full PDF toolkit, deep text readability analysis — sit beside everyday essentials, all sharing the same attention to interface, typography, and detail. Every calculation runs entirely on your device; nothing ever reaches a server. And every word is hand-translated into 20 languages, not auto-generated — because a tool built with care deserves to feel native everywhere.

Runs 100% in your browser Web Crypto API — not Math.random() Available in 20 languages 100% free · No account · No paywall

starTools Worth Knowing About

Most of these tools cover common ground. A few go further — solving problems that are surprisingly hard to find good online tools for.

Privacy-first vpn_keyAsymmetric Key Generator

Generates RSA and EC key pairs entirely in your browser using the Web Crypto API. Your private key never leaves your device — a genuinely rare capability among web tools.

 Finance real_estate_agentBuy vs Rent Calculator

A proper financial model comparing homeownership and renting over time, factoring in opportunity cost, rent growth, and home appreciation. Most sites only show you one side of the equation.

 Developer text_formatVariable Naming Converter

Paste any identifier or phrase and instantly get camelCase, PascalCase, snake_case, kebab-case, SCREAMING_SNAKE_CASE, and more — all conversions at once, in one place.

 Developer timerCron Expression Parser

Paste a cron expression and get a plain-English explanation plus the next scheduled run dates. A practical sanity-check before deploying any scheduled job or automation.

 Privacy-first keySymmetric Key Generator

Generates cryptographic-grade AES keys (128, 192, or 256-bit) in-browser via the Web Crypto API. Proper randomness — not Math.random() — for use in real encryption scenarios.

paymentsMoney

trending_upInvestment Calculator See how your money grows over time with compound interest houseMortgage Calculator Monthly payment, total interest, and year-by-year amortization account_balanceLoan Calculator Monthly payment, total interest, and amortization schedule savingsSavings Goal Calculator Plan how to reach your savings goal over time currency_exchangeCurrency Converter Convert between world currencies with live rates real_estate_agentBuy vs Rent Calculator Compare buying a home versus renting and investing the difference elderlyRetirement / FIRE Calculator Plan retirement with compound growth, inflation, and the 4% rule

codeDevelopment

data_objectJSON Formatter Format, minify, sort keys, stringify, and destringify JSON swap_horizBase64 Encoder/Decoder Encode text to Base64 or decode Base64 back to text linkURL Encoder/Decoder Encode or decode URL components fingerprintHash Calculator Calculate SHA-256, SHA-384, SHA-512, SHA-1, or MD5 hashes scheduleUnix Timestamp Converter Convert between Unix timestamps and human-readable dates manage_searchRegex Tester Test regular expressions with match highlighting and capture groups text_formatVariable Naming Converter Convert text between camelCase, snake_case, kebab-case, PascalCase, and more paletteColor Converter Convert between HEX, RGB, and HSL with live preview format_list_numberedSequence Generator Generate numeric sequences with custom prefix, suffix, and separator keySymmetric Key Generator Generate random AES keys in hex, Base64, or raw bytes vpn_keyAsymmetric Key Generator Generate RSA or EC key pairs in PEM format tagUUID Generator Generate random UUIDs (v4) in bulk timerCron Expression Parser Parse cron expressions into plain English sync_altYAML / JSON Converter Convert between YAML and JSON formats differenceDiff Checker Compare two texts and highlight the differences enhanced_encryptionAES Text Encryption Encrypt and decrypt text with AES-256-GCM and a password verified_userJWT Decoder & Verifier Decode JWT header and payload, verify the signature client-side

casinoRandom

shuffleRandom Picker Pick one or more random items from a list pinRandom Number Generator Generate random numbers within a range reorderList Randomizer Shuffle any list instantly monetization_onCoin Flip Flip a coin one or more times casinoDice Roller Roll dice of any type with statistics

handymanEveryday

passwordPassword Generator Generate strong, random passwords qr_codeQR Code Generator Create QR codes from text or URLs percentPercentage Calculator Calculate percentages, ratios, and percentage changes text_fieldsWord & Character Counter Count words, characters, sentences, and estimate reading time monitor_weightBMI Calculator Calculate Body Mass Index with health categories hourglass_emptyCountdown Timer Count down to any date with live updating contrastColor Contrast Checker Check WCAG AA/AAA color contrast for accessibility menu_bookText Readability Analyzer Score text with Flesch, Flesch-Kincaid, Gunning Fog, SMOG, and more picture_as_pdfPDF Toolkit Merge, split, and rotate PDFs privately in your browser

rocket_launchA Toolkit That Keeps Growing

New tools are added regularly, shaped by what users actually need. The roadmap is open: if something useful is missing, it can be requested. Every message is read, and the most-requested tools get prioritized for the next release.

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All tools run entirely in your browser. No data is sent to any server.