Zenvi Tools – 36+ Free Online Utility Tools
Free browser-based tools for image editing, PDF management, financial calculations, text processing, and more. No account required. No software to install. All processing happens locally in your browser.
Enable JavaScript to use these tools interactively. All 36+ tools run directly in your browser — your files and data never leave your device.
All image tools run entirely in your browser using the HTML5 Canvas API. Your photos are never uploaded to any server — everything is processed locally. Safe for personal, confidential, and proprietary images.
Convert images between JPG, PNG, WEBP, GIF, and BMP formats. Supports batch conversion of multiple files at once. Adjust output quality and download instantly. Ideal for preparing images for web, print, or app development.
Resize images to any custom pixel dimension. Lock the aspect ratio to prevent distortion. Quick presets for Instagram, YouTube thumbnails, Facebook posts, Twitter headers, favicons, and web banners. Output in PNG, JPG, or WebP format.
Reduce image file sizes by up to 90% with no visible quality loss. Compress multiple images simultaneously in one session. Adjust quality slider (10–100%) and choose output format. Shows original size, compressed size, and percentage saved per image.
Crop images with a visual drag-and-drop interface. Enter exact pixel coordinates (X, Y, Width, Height) for precise crops. Supports PNG, JPG, and WebP output. Perfect for social media aspect ratios, profile photos, product images, and presentation slides.
Remove image backgrounds automatically to produce a clean transparent PNG. Uses browser-based machine learning to isolate subjects. Ideal for product photography, print-on-demand designs, and profile pictures for professional platforms.
Detect and remove watermarks automatically using tile-frequency analysis and inpainting reconstruction. Adjust sensitivity slider to control aggressiveness. For legal use only — requires confirmation that you own or have permission to modify the image.
Our PDF tools use pdf-lib, a pure JavaScript PDF library, to process all documents locally in your browser. No PDF is ever uploaded to any server, making these tools safe for legal, financial, medical, and confidential documents.
Create a new PDF document from scratch by entering a title and body text directly in the browser. Customize formatting and download the completed PDF instantly. No Microsoft Word, Google Docs, or Adobe Acrobat needed.
Convert one or multiple images (JPG, PNG, WEBP) into a single PDF document. Drag to arrange image order, set page size (Letter, A4, or fit-to-image) and orientation. Download the finished PDF in seconds.
Combine multiple PDF files into a single merged document. Drag and drop to reorder files before merging. Displays the page count and file size for each uploaded PDF. Download the merged result instantly.
Reduce PDF file size by removing metadata, enabling cross-reference object streams, and eliminating redundant data. Three levels: Maximum Compression, Balanced, and Best Quality. Shows before/after size comparison and percentage saved.
Extract all readable text from a PDF file without uploading it. Uses a pure JavaScript byte-stream parser that reads BT/ET text blocks and Tj/TJ operators directly. Works on text-based PDFs without any external library dependency.
Add text annotations to any PDF by clicking directly on the page preview to place labels. Set font size and color per annotation. Edit or remove annotations before downloading the finalized PDF with all annotations embedded.
Free Online Calculators
Our financial and health calculators use established, peer-reviewed formulas to give you accurate, actionable results with clear explanations. Every calculation happens instantly in your browser — no form submission or data collection.
Calculate monthly mortgage payments including principal, interest, property taxes, and homeowner's insurance. View a full amortization schedule showing year-by-year balance reduction. Common presets for 15-year and 30-year fixed-rate mortgages.
Calculate monthly payments, total interest paid, and view a month-by-month amortization schedule for personal loans, auto loans, and student loans. Quick presets for typical loan scenarios. Shows principal vs. interest breakdown as a visual bar.
See how investments grow over time with compound interest and optional monthly contributions. Choose compounding frequency (daily, monthly, quarterly, annually). Visualize year-by-year growth with a color-coded bar chart distinguishing contributions from earned interest.
Convert between 30+ world currencies using live exchange rates updated daily from open.er-api.com. Covers USD, EUR, GBP, JPY, CAD, AUD, CHF, CNY, INR, BRL, MXN, KRW, SGD, ZAR, AED, and more. Falls back to cached rates when offline.
Calculate your BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure) using the Mifflin-St Jeor equation — validated as the most accurate BMR formula for most adults. Supports metric and imperial. Shows calorie targets for weight loss, maintenance, and muscle gain.
Calculate your Body Mass Index in metric or imperial units. Displays BMI category (Underweight, Normal weight, Overweight, Obese) and your healthy weight range for your height, based on WHO standards.
Solve common percentage problems: what is X% of Y, what percentage is X of Y, percentage increase or decrease between two numbers, and reverse percentage calculations. Multiple modes with instant results and formula explanations.
Convert between units of length, weight/mass, temperature, volume, speed, area, digital storage, and energy. Covers metric, imperial, and US customary units with instant results across all conversion pairs simultaneously.
Calculate the tip amount and total bill for restaurant dining and other services. Set tip percentage (5–30%), split between any number of people, and see exact per-person totals including both tip and bill share.
Free Text & Writing Tools
Our text tools help writers, editors, content marketers, students, and developers work with text faster and more accurately. All tools are browser-based and process your text locally with no data collection.
Count words, characters (with and without spaces), sentences, paragraphs, and estimated reading time. Paste any text and get live statistics that update as you type. Useful for essays, blog posts, social media limits, and SEO content requirements.
Instantly convert text between uppercase, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case. All conversions display simultaneously — copy any variant with one click.
Generate placeholder lorem ipsum text in any amount for mockups, wireframes, prototypes, and design presentations. Choose paragraphs, sentences, or words as the unit. Copy generated text instantly.
Compare two text blocks side-by-side to find additions, deletions, and changes. Highlights differences line-by-line with color coding. Useful for document version comparison, code review, and proofreading contract revisions.
Search for words or phrases in a block of text and replace all or specific instances. Supports case-sensitive matching and whole-word-only replacement. Displays the total replacement count after processing.
Purpose-built utilities for web developers, software engineers, and technical users. Each tool handles a specific everyday task that developers repeat constantly — format JSON, encode URLs, pick colors, generate passwords, or create QR codes.
Format and beautify raw JSON with proper indentation and syntax highlighting. Validate JSON and detect syntax errors with line-number references. Minify JSON to reduce payload size. Supports formatting large JSON objects from API responses.
Encode special characters in URLs to percent-encoded format, or decode percent-encoded strings back to readable text. Handles both full URL encoding and query-parameter-specific encoding. Essential for building and debugging web applications and API integrations.
Select any color visually using a color wheel and get the exact HEX, RGB, HSL, and CSS variable values. Browse curated color palettes for inspiration. One-click copy for any color format. Useful for CSS development, UI design, and brand color matching.
Generate cryptographically random passwords with custom length (4–64 characters) and character sets (uppercase, lowercase, numbers, symbols). Real-time password strength indicator. Generate multiple passwords at once for bulk account creation.
Generate QR codes for URLs, plain text, email addresses, phone numbers, Wi-Fi credentials, and contact cards. Customize size and foreground/background colors. Download QR codes as high-resolution PNG images. Fully browser-based with no server calls.
Calculate exact age in years, months, and days from any birthdate. Also shows total days lived, next birthday countdown, and the day of the week you were born. Useful for birthday planning, age verification, and milestone tracking.
Count down to any future date and time showing days, hours, minutes, and seconds remaining. Set custom event names. Useful for product launches, event planning, exam countdowns, and personal goal deadlines.
Generate random integers within any custom range. Generate single numbers or bulk lists of random numbers. Uses the browser's cryptographically secure random number API. Ideal for games, raffles, statistical sampling, lottery picks, and programming tests.
Convert typed text to spoken audio using your browser's Web Speech API. Select from available system voices, adjust speaking rate and pitch. Download the audio in multiple formats: WAV, WebM, Ogg, and more. Useful for accessibility, language learning, and content creation.
View the current local time, date, timezone, and live weather conditions. Auto-detects your location or look up any city by name. Displays temperature, humidity, wind speed, and conditions using the Open-Meteo weather API — no API key or account needed.
Blog: Free Guides and Tutorials
The Zenvi Tools blog publishes in-depth guides, tutorials, and practical tips covering image optimization, PDF management, personal finance, web development tools, and everyday online productivity. New articles publish three times per week following a Monday, Wednesday, Friday schedule.
Featured articles include: How to Compress Images for Faster Websites, PDF Editing Online: A Complete Guide, Compound Interest Basics, Using a Currency Converter for Travel and Business, Calorie Counting: A Practical Guide, and Image Cropping for Social Media. Browse the full archive at zenvitools.com/blog.
About Zenvi Tools
Zenvi Tools was created to give everyone access to professional-grade browser utilities — completely free, with no account required and no data collection. Every tool processes your files locally in your browser so your data never leaves your device. Whether you need to compress a photo before emailing it, calculate loan payments before signing a contract, convert currencies for a trip, or format JSON while debugging an API — Zenvi Tools has the right free tool for the job.
We publish new tools and articles regularly. Questions or feedback are welcome at hello@zenvitools.com. Learn more on our About page.