⭐ Starlight Tools — Free Online Calculators, Converters, Generators & Image Tools

Starlight Tools offers over X free, privacy-preserving, lightweight browser-based tools — including calculators, converters, and random generators — for image editing, PDFs, web development, text, time & date, finance, and science. Everything runs locally using JavaScript — nothing is uploaded, and your files never leave your computer. Our growing collection covers image editing, PDF and document utilities, calculators, finance tools, web development helpers, text processing, time & date tools, and science & research calculators. All tools are fast, ad-minimal, and built for instant results.
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Our top tools searched in Google

PDF Merger preview

PDF Merger

Combine multiple PDF files into one single document. No server upload. v1.0

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Keyword Density Checker preview

Keyword Density Checker

Analyze the frequency of keywords and phrases in your text for SEO. v1.0

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UNIX Timestamp Converter preview

⏱️ Timestamp Converter

Convert UNIX timestamps to human-readable dates and vice versa. v1.0

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Molarity Calculator preview

Molarity Calculator

Calculate mass, molecular weight, volume, or concentration for chemical solutions. v1.1

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Image & Graphics (13 tools)

PDF & Documents (7 tools)

Text Processing (12 tools)

Web Development (22 tools)

Financial Calculators (80 tools)

Health & Fitness Calculators (14 tools)

Geometry (32 tools)

Calculators (36 tools)

Time & Date Tools (26 tools)

Science & Engineering (53 tools)

Random Generators (22 tools)

Environment Tools (23 tools)

Games (14 tools)

Fun Calculators (17 tools)

Latest Update

🌍 October 18, 2025: We deployed our new Environment tools — starting with the Reusable Cup Impact Calculator. Friendly, transparent, and 100% client-side. 🌟
🌟 October 4, 2025: We added a Fan Art and Wallpapers page.
🌟 September 14, 2025: We are quietly improving the design of all of our tools.
🌟 September 12, 2025: We are proud to deploy our 200th tool, a typing training game: Emoji Catcher. Our Dilution Calculator has also recieved a v1.1 update. 🌟
🧪 August 30, 2025: Added two interactive simulations — Conway’s Game of Life and an Ant Colony Simulator — both run fully in your browser. 🌟
🎮 August 18, 2025: We’ve added a new Games section! Play simple, fun browser-based games — no installs, just instant play. 🌟
🌟 August 15, 2025: Our HTML Colour Picker now includes example panels for quick inspiration and one-click copy. Explore ready-made swatches and preview variations instantly. 🌟
🌟 August 15, 2025: Timestamp Converter now supports nanoseconds (ns) in addition to seconds, milliseconds, and microseconds — with clean ISO-8601 output. 🌟
🌟 August 15, 2025: Browser Info shows more data and a clearer summary panel for faster debugging and shareable diagnostics. 🌟
🌟 August 4, 2025: We are organizing our tools into neat categories. 🌟
🌟 August 2, 2025: Our Image Resizer & Converter has been updated to v1.1 with enhanced high-quality scaling! Images now resize much more smoothly with improved interpolation, resulting in cleaner, less pixelated results. 🌟
🌟 July 30, 2025: We have deployed a new category "Utility tools" and our 50th tool - GPA Calculator. 🌟.
🌟 July 29, 2025: You can also find us on X: @starlightrobotx. 🌟.
🌟 July 27, 2025: We have rolled out our first offline product. The Starlight Batch Image Resizer and Converter. 🌟.
🌟 July 14, 2025: For stargazing enthusiasts, we are beginning development of a Star Field Planeratium, using the 2024 HYG 4.1 dataset. 🌟.
🌟 July 12, 2025: In addition to our Life Science calculators, we are adding a few calculators from space, for those who would like to have a look at the stars 🌟.
🌟 July 7, 2025: We are proud to announce that we have deployed 30 tools to help you with small but much needed tasks.
🌟 July 3, 2025: We are expanding. We now have a new category of Scientific Tools for unique research tasks.
🌟 July 3, 2025: We've added a predictive search bar for your convenience, as we already have over 20 tools. This way you can find tools even faster!
🌟 July 2, 2025: We've just added useful tips and facts to several of our popular tools! Now you'll find detailed explanations right on the page. These additions are designed to help you get the most out of our tools and learn something new!
🌟 June 30, 2025: Major upgrade to the Image Resizer & Converter tool! Now supporting batch processing for up to 10 images, with global resizing controls and convenient ZIP file downloads for all converted images. This significantly enhances efficiency for bulk image operations! (v2.0)
🌟 June 28, 2025: New HTML Colour Picker and Markdown to HTML Converter tools launched!
🌟 June 23, 2025: New Case Converter tool launched! Easily convert text to CAPITAL, lowercase, capitalized, sentence case, and alternating case.
New Alphabetic Numeric Sorter tool launched! Easily sort lines of text alphabetically or numerically.
Add Text to Image tool. Release v1.3. Added features: Bold, Italic, Underline. More visible fonts. Border, Border thickness, and Border colour.
🌟 June 23, 2025: Exciting news! We've launched our new PDF Merger tool. Now you can easily combine multiple PDF files into one directly in your browser. We also launched our new Word Counter tool! Easily count words, characters, numbers, punctuation, spaces, and new lines
🌟 June 14, 2025: We've launched our new Image Resizer & Converter tool. Now you can easily resize images and convert between various formats directly in your browser. We also launched a PDF to Image splitter tool, that allows you to break a PDF document into multiple individual files.
🌟 June 13, 2025: We've launched our first two tools — Add Text to Image and QR Code Generator. Each runs fully in your browser, with no data leaving your device.
🌟 June 11, 2025: Our site is live. Welcome to the first public deployment of Starlight Tools.