90 Free Online Tools — PDF, Image, Singapore Finance, Event & Developer Utilities

Kova Core is a privacy-first suite of 90 free browser-based utilities. Merge, split, sign, and compress PDFs, extract text with offline OCR, protect NRIC/ID copies, calculate Singapore CPF and property stamp duty, generate PayNow SGQR codes, spin a Lucky Draw prize wheel, roll 3D multi-skin dice, and format developer code — 100% locally in your browser with no file uploads and no sign-up required.

Document & PDF Utilities

PDF Organizer Pro — Merge, split, reorder, and insert pages visually.
Image to Text (OCR) — Copy text from photos, screenshots and scanned PDFs.
Sign PDF — Draw or type your signature and place it on a PDF.
PDF to JPG / PNG — Convert PDF pages into high-resolution JPG or PNG images.
JPG / PNG to PDF — Combine multiple photos or scans into one PDF document.
PDF Invoice Generator — Create downloadable PDF invoices and receipts with GST.
PDF Merger — Combine multiple PDF files into a single document.
PDF Splitter — Split a PDF into separate pages or ranges.
PDF Compressor — Reduce PDF file size while preserving quality.
PDF Watermark & Stamp — Add visual checkprint chops and watermarks.

Privacy & Safety

ID Copy Protector — Black out details and watermark your IC or passport copy.
QR Code Safety Checker — See where a QR code really leads before you open it.
Photo Location Remover — See and remove the hidden GPS location in your photos.

Image & Graphic Utilities

Image Compressor — Shrink JPG, PNG, WebP up to 90% without quality loss.
Passport & IC Photo Maker — Crop photos to Singapore ICA 400x514px, US 2x2, and visa sizes.
Favicon & App Icon Pack — Generate 16x16 to 512x512 favicons and Apple Touch icons.
Aspect Ratio Calculator — Calculate 16:9, 9:16, and custom video/image dimensions.
Color Contrast Checker — Test text and background colors for WCAG AA/AAA compliance.
Pro Image Editor — Crop, resize, and preview images visually.
Color Picker — Pick colors from uploaded images interactively.
HEIC to JPG — Convert iPhone HEIC photos to standard JPG/PNG.
WebP Converter — Convert WebP to JPG or PNG easily.
SVG Converter — Convert SVG vectors to high-res PNG/JPG.
CSS Gradient — Generate linear CSS gradients.

Essential Power Tools

ZIP Compressor — Compress multiple large files into a ZIP securely.
Cron Expression Generator — Build and translate Linux cron schedules into plain English.
Chmod Calculator — Convert Linux file permissions between 755 octal and rwx.
Number Base Converter — Convert numbers between Hex, Decimal, Binary, and Octal.
Epoch Converter — Convert Unix timestamps to human dates.
Text ⇌ ASCII — Convert letters into ASCII decimal numbers.
Box Shadow Generator — Visually create beautiful CSS box shadows.
HTML Entity Encoder — Safely escape HTML entities and tags.
JSON Minifier — Minify and compress JSON structures.
String Generator — Generate secure random tokens and strings.

Developer Utilities

JSON Formatter — Beautify, validate, and minify JSON code.
JSON to TypeScript — Generate TypeScript interfaces from any JSON payload.
PayNow QR Generator — Create SGQR PayNow QR codes for Mobile or UEN with amount.
Base64 Encoder — Encode or decode strings to Base64.
Hash Generator — Generate secure MD5, SHA-1, SHA-256 hashes.
URL Encoder — Encode or decode URL strings safely.
QR Generator — Generate and download custom QR codes.
JSON ⇌ CSV — Convert arrays of JSON objects to CSV.
Password Generator — Create secure random passwords.
Text ⇌ Binary — Convert standard text into binary code.

Formatting & Conversion

XML Formatter — Format, beautify, and minify XML.
SQL Formatter — Beautify messy SQL queries for multiple dialects.
Web Code Beautifier — Instantly format HTML, CSS, and JS.
CSV to JSON — Convert CSV datasets into JSON arrays.
XML ⇌ JSON — Convert structures between XML and JSON.
URL Parser — Extract domains and query params from URLs.

Math & Finance

SG CPF Salary Calculator — Calculate Singapore CPF contributions and take-home salary.
BSD & ABSD Stamp Duty — Calculate Singapore property BSD, ABSD, and monthly mortgage.
Compound Interest — Project investment portfolio growth with monthly contributions.
Currency Converter — Live exchange rates for global currencies.
Loan Calculator — Calculate mortgage and loan payments.
Percentage Calculator — Instantly solve percentage math problems.
Discount & Tax — Calculate final prices after discounts and sales tax.
Split Bill Calculator — Split a bill equally or by items, with service charge and GST.
Salary Converter — Convert wage between hourly, monthly, and yearly equivalents.

Network & Security

JWT Decoder — Decode JSON Web Tokens securely.
Bcrypt Generator — Hash passwords and verify Bcrypt matches.
User-Agent Parser — Extract OS and browser from UA strings.
UUID Generator — Generate completely random UUIDs.
MAC Address Generator — Create random MAC addresses for testing.

Web Utilities

WhatsApp Link Generator — Create wa.me click-to-chat links and QR codes with pre-filled text.
IP Locator — Find geographic details of an IP or domain.
HTTP Status Codes — Quick dictionary for HTTP status codes.
Regex Tester — Test regular expressions directly in the browser.
JS Keycode Info — Get Javascript event keycodes instantly.

Miscellaneous

Lucky Draw Wheel — Spinning prize roulette with Excel import, photos, and winner removal.
3D & Couples Dice Roller — Roll D6, RPG D20, Poker dice, or Couples date-night dice with skins.
Morse Code Translator — Convert text to Morse code and play radio telegraph audio beeps.
Pomodoro Timer — Boost your productivity with timed focus sessions.
JSON Validator — Strictly validate JSON to find syntax errors.
Text to Speech — Convert text into realistic browser speech.
Speech to Text — Dictate sentences using your microphone.
BMI Calculator — Calculate your Body Mass Index (Metric & Imperial).

Everyday Tools

Age & Business Days — Calculate exact age and working weekdays between two dates.
Timezone Meeting Planner — Compare SGT, UTC, Tokyo, London, and NY hours side by side.
Stopwatch & Timer — A beautiful stopwatch and countdown timer.
Basic Calculator — A simple, clean calculator for daily use.
Random Generator — Roll dice, flip coins, or get random numbers.
Unit Converter — Convert length, weight, temperature, area, volume, speed, time, and data storage.

Text & Writing Utilities

Duplicate & Text Cleaner — Remove duplicate lines, empty spaces, and HTML tags in one click.
Case Converter — Convert text to UPPERCASE, lowercase, and more.
Lorem Ipsum — Generate random placeholder text easily.
Word Counter — Count words, characters, and reading time.
Text Diff Checker — Compare two pieces of text and find differences.
Slug Generator — Create SEO-friendly URL slugs from titles.
Markdown ⇌ HTML — Convert Markdown to HTML and vice-versa.

Original Tech, Privacy & AI Guides

The Generations of AI Explained: How Smart Is AI in 2026? — From chess computers to ChatGPT to AI agents: a plain-English tour of each generation of artificial intelligence, what changed each time, and an honest look at how smart today's AI really is — and where it still fails.
How to Use ChatGPT, Claude and Gemini: A Beginner's Guide — Most people use AI chatbots like a search box and get average answers. These simple habits — context, examples, format and follow-ups — get you far better results from ChatGPT, Claude, Gemini or any AI assistant.
ComfyUI for Beginners: Make Your First AI Image, Step by Step — ComfyUI looks intimidating — boxes and wires everywhere — but it is the most flexible free way to create AI images on your own computer. This guide covers installation, every node in the default workflow, and the settings that actually matter.
How to Run AI on Your Own Computer (Free and Private) — You don't need a subscription to use a capable AI chatbot. With free apps like LM Studio and Ollama you can run open AI models on your own PC or Mac — offline, private and free. Here is the hardware you need and how to start in 10 minutes.
How to Spot AI Scams and Deepfakes: A Singapore Guide — Scammers now use AI to clone voices, fake video calls and write flawless messages. Singapore lost S$913 million to scams in 2025. Here are the warning signs, real examples, and the simple habits that protect you and your family.
Trust Bank Referral Code DKNSEX44: 2026 Sign-Up Guide — Signing up for Trust Bank in Singapore? Enter referral code DKNSEX44 in the app to get a sure-win cashback scratch card. Here is how the referral works, what the Trust cards offer, and what to check before you apply.
Why Every Developer Needs a Local JSON Formatter in 2026 — Working with APIs can be a nightmare without the right tools. Here is why a fast, browser-based JSON formatter is essential for modern web development.
How to Merge, Split, and Compress PDF Files for Free (No Software, No Uploads) — You don't need Adobe Acrobat or a sketchy "free PDF tool" website that uploads your documents to a server. Here's how to merge, split, reorder, and shrink PDF files entirely in your browser.
12 Free Online Developer Tools Worth Bookmarking in 2026 — From decoding a JWT to testing a regex pattern, these are the small utilities that quietly save developers the most time — all free, all running locally in your browser.
How to Create Unbreakable Passwords in 2026: The Math Behind Password Security — With GPU clusters testing billions of password hashes per second, human-chosen passwords fail faster than ever. Here is how cryptographic entropy works and how to secure your accounts effortlessly.
Sharing Your NRIC, Passport or ID Copy in Singapore? How to Protect Yourself — When renting a flat, applying for a job, or signing up for telco plans, you are often asked for an ID scan. Here is what Singapore PDPA rules say and how to watermark your documents locally so they cannot be misused.
Essential Singapore Money & Business Tools: CPF Take-Home Pay, BSD/ABSD & PayNow QR Explained — Whether you are calculating your net salary after CPF, budgeting for Buyer's Stamp Duty on a condo or HDB flat, or generating a PayNow QR code for an invoice, here is how the numbers work in 2026.
How to Run a Fair, Transparent Lucky Draw for Company D&D, Schools & Live Events — Planning a corporate Dinner & Dance, wedding giveaway, or classroom raffle? Here is how to import your guest list from Excel, set up prize tiers, and run an interactive roulette wheel on the big screen.