# CrizaTools

> CrizaTools is a free collection of online tools for small businesses and everyday work: GST invoices, QR codes, WhatsApp links, calculators and text tools that run in your browser, made by Criza Labs.

All tools are free, need no sign-up and run in the visitor's browser; tool input is not uploaded. Published by Criza Labs (https://criza.dev), Gujarat, India. Contact: info@criza.dev.

## PDF, image, text and code

- [JPG to PDF](https://tools.criza.dev/jpg-to-pdf/): A JPG to PDF converter places each image on its own PDF page and saves them as one file. This one runs in your browser with the open-source pdf-lib library, so private documents such as Aadhaar or marksheets are never uploaded to a server.
- [Merge PDF](https://tools.criza.dev/merge-pdf/): Merging PDFs copies every page from each file, in the order you choose, into one new PDF. This tool does it in your browser with pdf-lib, so the documents are never sent to a server, which matters for bank statements and ID papers.
- [Image Compressor](https://tools.criza.dev/image-compressor/): Image compression re-saves a picture with a more efficient format and quality setting, and resizing reduces its pixel dimensions. Together they often cut a phone photo from several megabytes to a few hundred kilobytes with little visible change.
- [Word Counter](https://tools.criza.dev/word-counter/): A word counter splits text into words at spaces and punctuation and counts them, along with characters, sentences and paragraphs. Reading time here assumes about 225 words a minute and speaking time about 140.
- [Case Converter](https://tools.criza.dev/case-converter/): A case converter changes the capitalisation of text without retyping it: all capitals, all small letters, sentence case, title case, or programmer styles such as camelCase and snake_case that also remove spaces.
- [Password Generator](https://tools.criza.dev/password-generator/): A strong password is long and random. Each extra character multiplies the number of possible passwords, so 16 random characters from letters, numbers and symbols give over 100 bits of randomness, far beyond what guessing attacks can reach.
- [JSON Formatter](https://tools.criza.dev/json-formatter/): A JSON formatter parses JSON text and prints it again with consistent indentation, one key per line, so it is easy to read. If the text is not valid JSON, parsing fails and the formatter reports where. Minifying does the reverse: it removes every space and line break that is not inside a string.
- [JWT Decoder](https://tools.criza.dev/jwt-decoder/): A JWT (JSON Web Token) is three Base64URL-encoded parts joined by dots: a header naming the signing algorithm, a payload of claims such as sub, iat and exp, and a signature. Decoding reads the first two parts. It does not prove the token is genuine; only checking the signature with the right key does that.
- [Base64 Encode & Decode](https://tools.criza.dev/base64-encode-decode/): Base64 writes any data using 64 safe characters (A–Z, a–z, 0–9, + and /), so it can travel through email, JSON and URLs. Every 3 bytes become 4 characters, so encoded text is about a third larger. It is an encoding, not encryption: anyone can decode it.

## Calculators

- [GST Calculator](https://tools.criza.dev/gst-calculator/): To add GST, multiply the base price by (1 + rate ÷ 100). To remove GST from an inclusive price, divide it by (1 + rate ÷ 100). Inside one state the tax is split equally into CGST and SGST; between states it is charged as IGST.
- [EMI Calculator](https://tools.criza.dev/emi-calculator/): EMI (equated monthly instalment) = P × r × (1 + r)ⁿ ÷ ((1 + r)ⁿ − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the number of months. Early EMIs are mostly interest; later ones are mostly principal.
- [SIP Calculator](https://tools.criza.dev/sip-calculator/): SIP future value = P × [((1 + i)ⁿ − 1) ÷ i] × (1 + i), where P is the monthly investment, i is the monthly return (annual ÷ 12 ÷ 100) and n is the number of months. It assumes a constant return, which real markets never deliver, so treat the result as an estimate.
- [VAT Calculator](https://tools.criza.dev/vat-calculator/): To add VAT, multiply the net price by (1 + rate ÷ 100): £100 plus 20% VAT is £120. To remove VAT from a gross price, divide by (1 + rate ÷ 100): £120 ÷ 1.2 = £100, so the VAT inside it is £20, not 20% of £120.
- [Sales Tax Calculator](https://tools.criza.dev/sales-tax-calculator/): Sales tax = price × rate ÷ 100, and the total is price × (1 + rate ÷ 100). At 8.25%, an $80 item has $6.60 tax and costs $86.60. To reverse it, divide the total by (1 + rate ÷ 100): $107 at 7% is a $100 price plus $7 tax.
- [Percentage Calculator](https://tools.criza.dev/percentage-calculator/): A percentage is a number out of 100. X% of Y = Y × X ÷ 100. X as a percent of Y = X ÷ Y × 100. Percentage change = (new − old) ÷ old × 100.
- [Age Calculator](https://tools.criza.dev/age-calculator/): Exact age is counted as complete years since the date of birth, then complete months, then remaining days, borrowing the number of days in the previous month when needed.
- [FD Calculator](https://tools.criza.dev/fd-calculator/): FD maturity = P × (1 + r/n)^(n × t), where P is the deposit, r the yearly rate as a decimal, n the number of compounding periods a year (4 for quarterly) and t the years. ₹1,00,000 at 7% for 3 years compounded quarterly matures at about ₹1,23,144.
- [Compound Interest Calculator](https://tools.criza.dev/compound-interest-calculator/): Compound interest A = P × (1 + r/n)^(n × t); simple interest SI = P × r × t ÷ 100. With compounding, interest is added to the balance and earns interest itself, so ₹50,000 at 8% for 10 years grows to about ₹1,10,982 compounded monthly, against ₹90,000 with simple interest.
- [BMI Calculator](https://tools.criza.dev/bmi-calculator/): BMI = weight in kg ÷ (height in metres)². A 170 cm, 68 kg adult has a BMI of 23.5. WHO calls 18.5–24.9 normal, but WHO and Indian guidelines suggest Asian adults treat 23 and above as overweight because health risks rise at lower BMI.
- [Discount Calculator](https://tools.criza.dev/discount-calculator/): Sale price = price × (1 − discount ÷ 100). For two discounts, apply the second to the already-reduced price: ₹2,499 with 40% + extra 10% off is ₹2,499 × 0.6 × 0.9 = ₹1,349.46, a total discount of 46%, not 50%.
- [Date & Days Calculator](https://tools.criza.dev/date-calculator/): Days between two dates is the end date minus the start date; most notice periods and payment terms count the start but not the end, which this calculator follows, and it also shows the count with the end date included. Working days exclude Saturdays and Sundays, not public holidays.

## QR codes

- [QR Code Generator](https://tools.criza.dev/qr-code-generator/): A QR code generator turns text, a web address or structured data such as Wi-Fi details into a square barcode that phone cameras read. This one makes static codes: the content is stored in the pattern itself, so the code never expires, has no scan limit and does not route through a tracking server.
- [UPI QR Code Generator](https://tools.criza.dev/upi-qr-code-generator/): A UPI QR code holds a upi://pay link containing your UPI ID (VPA), your name, and optionally an amount and note. Any UPI app that scans it opens a payment screen to you, where the payer checks the details and enters their PIN.
- [QR Code Scanner](https://tools.criza.dev/qr-code-scanner/): A QR code scanner decodes the pattern into its text: a web address, a UPI payment request, Wi-Fi details or a contact card. This scanner works in the browser using the built-in barcode detector where available and the open-source jsQR library elsewhere; images and camera frames stay on your device.
- [Wi-Fi QR Code Generator](https://tools.criza.dev/wifi-qr-code-generator/): A Wi-Fi QR code stores your network name (SSID), password and security type in the standard WIFI: format. iPhone and Android cameras recognise it and offer to join the network in one tap.
- [Contact Card QR (vCard)](https://tools.criza.dev/vcard-qr-code-generator/): A vCard QR code holds a contact card in the vCard format: name, phone numbers, email, company, job title, website and address. Scanning it opens the phone's 'add contact' screen with every field filled in.

## Business

- [GST Invoice Generator](https://tools.criza.dev/gst-invoice-generator/): A GST invoice generator is a form that lays out a tax invoice for you and does the tax arithmetic. This one runs entirely in your browser: what you type is not uploaded, and you save the finished invoice as a PDF from the print window.
- [WhatsApp Link Generator](https://tools.criza.dev/whatsapp-link-generator/): A WhatsApp link is a web address in the form wa.me/<number> that opens a chat with that number in one tap, on phone or computer. Adding ?text= after it pre-fills a message the customer can edit before sending. The QR code holds the same link.
- [Number to Words (Rupees)](https://tools.criza.dev/number-to-words/): Indian numbering groups digits as thousand, lakh (1,00,000) and crore (1,00,00,000), so 12,50,000 is twelve lakh fifty thousand. International numbering groups by thousands, so the same 1,250,000 is one million two hundred fifty thousand. Cheques in India are written in the Indian system, ending in 'Only'.
- [Google Review QR Card](https://tools.criza.dev/google-review-qr-code/): A Google review QR code is a QR code that opens the 'write a review' box for your Google Business Profile. Customers scan it with their phone camera, rate you and write a review without searching for your business.
- [Website Launch Checklist](https://tools.criza.dev/website-launch-checklist/): A website launch checklist is a list of checks to finish before a site goes public: content, forms, search engine settings, speed, accessibility and ownership of accounts. It catches small mistakes that are cheap to fix before launch and costly after.
- [Project Brief Builder](https://tools.criza.dev/project-brief-builder/): A project brief is a short written summary of what you want built, for whom, what it must do, when you need it and your budget range. It makes quotes comparable and avoids surprises later.
- [Check Amount in Words](https://tools.criza.dev/check-amount-in-words/): On a US check, write the dollars in words, then 'and', then the cents as a fraction over 100: $1,234.56 becomes 'One thousand two hundred thirty-four and 56/100'. The word Dollars is usually printed at the end of the line. A whole-dollar amount ends in 'and 00/100'.

## Guides

- [EMI Formula Explained with Examples (Home, Car, Personal)](https://tools.criza.dev/guides/emi-formula-explained/): The EMI formula explained with rupee examples: why early EMIs are mostly interest, how tenure changes total cost, and when prepaying a loan saves most.
- [Free Billing Software for Small Business: What to Look For](https://tools.criza.dev/guides/free-billing-software-small-business/): How to choose free billing software for a shop in India: offline vs cloud, GST invoices, thermal printing, data ownership, hidden limits and open source.
- [GST Invoice Format: Every Field Explained (2026)](https://tools.criza.dev/guides/gst-invoice-format/): What a GST tax invoice must contain under Rule 46, when to use a bill of supply, how CGST, SGST and IGST appear, with a sample layout and common mistakes.
- [How to Calculate GST: Formulas, Examples and Mistakes](https://tools.criza.dev/guides/how-to-calculate-gst/): How to add GST to a price, remove it from an inclusive amount and split it into CGST, SGST or IGST, with rupee examples and the most common mistake.
- [How to Get More Google Reviews (Without Breaking Rules)](https://tools.criza.dev/guides/get-more-google-reviews/): Policy-safe ways for shops, clinics and local businesses to get more genuine Google reviews: the review link, QR cards, timing, replies and what to avoid.
- [How to Reduce Photo Size for Online Forms (Under 50 KB)](https://tools.criza.dev/guides/reduce-image-size-for-online-forms/): Shrink a photo or signature to the KB limit of exam, job and government forms without losing clarity: the right size, quality and format to use.
- [Static vs Dynamic QR Codes: Which Should You Use?](https://tools.criza.dev/guides/static-vs-dynamic-qr-codes/): The real difference between static and dynamic QR codes: expiry, scan limits, tracking, privacy and cost, plus design rules that keep a QR code scannable.
- [UPI QR Code for Your Shop: Setup, Safety and Printing](https://tools.criza.dev/guides/upi-qr-code-for-shop/): How a UPI QR code works, personal vs merchant UPI IDs, adding a fixed amount, printing a durable counter code and protecting your shop from QR code swap scams.
- [WhatsApp Click-to-Chat Links: A Guide for Businesses](https://tools.criza.dev/guides/whatsapp-business-link-guide/): How wa.me links work, adding a pre-filled message, where to place your WhatsApp link and QR code for more enquiries, and mistakes that break links.

## Related

- [CrizaVoise, free billing software](https://tools.criza.dev/free-billing-software/): CrizaVoise is free, open-source billing software for small businesses. It makes GST-ready invoices, prints thermal receipts and tracks payments and stock, fully offline on Windows, Linux and macOS. Download: https://voise.criza.dev/download/
- [Criza Labs](https://criza.dev): websites, apps and AI automation.

## Optional

- [Full text of every tool page and guide](https://tools.criza.dev/llms-full.txt)
- [Privacy policy](https://tools.criza.dev/privacy-policy/)