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.

Singapore, Money & Business

CPF & Take-Home Pay — Calculate monthly take-home pay & CPF (2026 rates).
Split Bill Calculator — Split restaurant bills equally or by item with GST.
Discount & GST Calculator — Final bill after discount, 10% service charge & 9% GST.
PayNow QR Generator — Create PayNow QR codes for Mobile or UEN with amount.
WhatsApp Link & QR — Make click-to-chat wa.me links & QR codes.
Stamp Duty (BSD & ABSD) — Property stamp duty, upfront cash & monthly mortgage.
PDF Invoice Generator — Create and download clean A4 PDF invoices.
Currency Converter — Convert SGD, USD, MYR, JPY & global currencies.
Loan & Mortgage — Monthly loan repayments and total interest.
Compound Interest — Project savings growth with monthly deposits.
Salary Converter — Convert between hourly, monthly & yearly pay.
Percentage Calculator — Quickly calculate % of a number or % change.

Games, Lucky Draw & Fun

Lucky Draw Wheel — Spin names & photos for prizes with winner removal.
3D Dice Roller — Throw realistic 3D dice into a tray (1–6, RPG & Couples).
Number & Lotto Picker — Pick random numbers, TOTO sets, or flip a coin.
Morse Code & Audio — Translate text to Morse code & play audio beeps.

PDF & Document Tools

PDF Organizer Pro — Reorder, rotate, merge & delete PDF pages visually.
PDF Merger — Combine multiple PDF files into one document.
PDF Splitter — Extract specific pages from any PDF file.
PDF Compressor — Shrink PDF file size for email or portal uploads.
Sign PDF — Draw or type your signature onto any PDF page.
PDF to JPG / PNG — Save PDF pages as high-resolution images.
JPG / PNG to PDF — Combine photos or scans into a single PDF.
Image to Text (OCR) — Copy text from photos, screenshots & scanned PDFs.
PDF Watermark & Stamp — Add diagonal watermarks or company chops to PDFs.
ZIP File Creator — Bundle multiple files into a single ZIP download.

Privacy, ID & Passwords

Password Generator — Create strong, unbreakable random passwords.
ID Copy Protector — Watermark & black out IC or passport copies safely.
QR Code Safety Checker — See where a QR code really leads before opening it.
Photo Location Remover — Remove hidden GPS location data from your photos.
Custom QR Generator — Make QR codes for links, Wi-Fi & contact cards.

Image & Photo Studio

Passport & IC Photo — Crop photos to SG ICA 400×514, US 2×2 & visa sizes.
Image Compressor — Shrink JPG, PNG & WebP up to 90% without blur.
Crop & Resize Image — Crop and resize images visually.
HEIC to JPG — Convert iPhone HEIC photos to standard JPG or PNG.
WebP Converter — Convert WebP images to JPG or PNG.
SVG to PNG / JPG — Convert vector SVG files into high-res images.
Image Color Picker — Pick exact HEX & RGB colors from any photo.
Favicon Generator — Export 16×16 to 512×512 website & app icons.
Aspect Ratio Calculator — Calculate 16:9, 9:16 & custom photo dimensions.

Everyday Life, Time & Writing

Unit Converter — Convert length, weight, temperature, area & volume.
Age & Working Days — Calculate exact age and weekdays between two dates.
World Timezone Planner — Compare Singapore, London, NY & Tokyo hours.
BMI & Calorie Calculator — Check BMI, healthy weight range & daily calories.
Basic Calculator — Simple everyday calculator with history tape.
Stopwatch & Timer — Stopwatch with laps and countdown alarm.
Pomodoro Focus Timer — 25-minute focus sessions with short breaks.
Word & Character Counter — Count words, characters, speaking & reading time.
Case Converter — Convert UPPERCASE, lowercase, Title Case & more.
Duplicate & Text Cleaner — Remove duplicate lines, extra spaces & HTML tags.
Text Diff Checker — Compare two blocks of text to spot changes.
Text to Speech — Read text aloud using natural browser voices.
Speech to Text — Dictate notes hands-free with your microphone.

Developer & Coding Tools

JSON Formatter — Beautify, validate, and inspect JSON payloads.
JSON to TypeScript — Generate TypeScript interfaces from JSON.
JSON Validator — Find exact line syntax errors in JSON.
JSON Minifier — Strip whitespace to compress JSON payloads.
JSON ⇌ CSV — Convert JSON arrays to CSV spreadsheets.
CSV to JSON — Parse CSV tables into structured JSON.
SQL Formatter — Format SQL queries across major dialects.
XML Formatter — Beautify and indent XML documents.
XML ⇌ JSON — Convert data between XML and JSON.
HTML / CSS / JS Formatter — Beautify minified web code.
Markdown ⇌ HTML — Preview and convert Markdown & HTML.
Regex Tester — Test regular expressions with live matches.
Cron Schedule Builder — Build cron schedules with plain-English preview.
Chmod Calculator — Convert Linux permissions (755 ⇌ rwxr-xr-x).
JWT Decoder — Inspect JWT headers, claims & expiry locally.
Base64 Encoder — Encode and decode Base64 text.
URL Encoder — Encode or decode URL query strings.
URL Parser — Break URLs into host, path & query params.
Hash Generator — Generate MD5, SHA-1, SHA-256 & SHA-512 hashes.
Bcrypt Hash & Verify — Hash passwords and test Bcrypt matches.
UUID Generator — Generate v4 UUIDs in bulk.
Random Token Generator — Generate API keys and random strings.
Epoch Timestamp — Convert Unix timestamps to readable dates.
Number Base Converter — Convert Hex, Decimal, Binary & Octal.
Text ⇌ Binary — Translate text to 8-bit binary code.
Text ⇌ ASCII — Convert characters to ASCII codes.
HTML Entity Encoder — Escape and unescape HTML entities.
Slug Generator — Turn article titles into clean URL slugs.
Lorem Ipsum — Generate placeholder paragraphs or words.
Color Contrast (WCAG) — Check text contrast for AA/AAA accessibility.
CSS Gradient — Create CSS linear gradients visually.
CSS Box Shadow — Design smooth CSS box shadows.
IP Address Lookup — Check IP geolocation, ISP & ASN.
User-Agent Parser — Decode browser and OS from UA strings.
HTTP Status Codes — Searchable guide to HTTP status codes.
JS Keycode Tester — Press any key to inspect JS key event values.
MAC Address Generator — Generate random test MAC addresses.

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.