Question 1

Do these QR codes expire or depend on this site staying online?

Accepted Answer

No — a QR code just encodes the text or link directly into its pattern; scanning it doesn't call back to CalcuOnline in any way. Once you've downloaded the image, it will keep working for as long as the underlying link or content (e.g. your Wi-Fi password, if you change it) stays valid.

Question 2

How does the UPI QR code work?

Accepted Answer

It builds a standard UPI deep link (upi://pay?...) with your UPI ID, name, and optional fixed amount — the same format GPay, PhonePe, and Paytm use for their own "Scan to pay" codes. Leave the amount at 0 to let the payer enter it themselves when they scan.

Question 3

Is my Wi-Fi password or UPI ID sent anywhere when I generate the code?

Accepted Answer

No — the QR code is generated entirely in your browser using a local library; nothing you type is uploaded or sent to a server. That said, treat the downloaded image itself as sensitive if it encodes a password or payment ID — anyone who scans it gets that information.

Question 4

PNG or SVG — which should I use?

Accepted Answer

PNG is a fixed-resolution image, good for pasting into documents, slides, or social posts at the size you generated it. SVG is vector-based and scales to any size (a poster, a shop banner) without going blurry — use it when you need to print large or resize later.

Type	Good for	Scans to
URL	Menus, portfolios, landing pages	Opens a webpage
UPI	Shop counters, invoices, donation drives	Opens payment app with amount pre-filled
Wi-Fi	Guest networks, cafés, offices	Connects automatically, no typing
WhatsApp	Business cards, support links	Opens a chat with your number
Text	Event details, short notes	Shows plain text on scan

QR Code Generator

Which QR type to use

Common questions