The short answer
A QR code is a printed square pattern that stores a short piece of text — usually a URL — which any phone camera can read in one snapshot and turn into an action like opening a page, joining WiFi, or adding a contact. They are free to generate and scan, they never expire as long as the printed pattern survives, and they work on every modern phone with no app installed. This page collects the questions people actually ask about QR codes in one place, with a short answer to each and a link to the full deep-dive guide on that topic.
The most common confusion comes from the static-vs-dynamic distinction, so it is worth stating up front: a static QR code bakes its data into the printed pattern and scans forever with no server, while a dynamic QR code stores only a short redirect link and looks up the real destination on a server — editable and trackable, but dependent on that server staying alive. Most of the “can a QR do X” questions below hinge on that one difference, which our static vs dynamic QR guide covers in full.
How to use this FAQ
Each question below gets a two-to-three sentence answer plus a plain-language pointer to the dedicated guide that goes deeper. If your question is here, click through to the linked guide for the full explanation, examples, and the scannability rules that matter when you actually generate and print a code. The “Keep learning” list at the bottom of the page links to every QRForge guide, so you can browse the whole library from here.
If you already have a QR code and need to check it, run the image through QRForge’s free decode helper, which reads a QR from an uploaded photo and tells you what it encodes. If you need to make one, every generator page on QRForge builds a static code in-browser for free with full styling and PNG/SVG/EPS export.
How QRForge can help
QRForge is a free, browser-side static QR code generator: all seven content types (URL, text, WiFi, vCard, SMS, email, event), deep customization (colors, gradients, per-eye and per-module shapes, centered logos, frames, error-correction control), vector SVG and EPS export plus high-res PNG, and a free batch CSV-to-ZIP mode. Everything runs in your browser, nothing is uploaded, and a free decode helper confirms your code round-trips before you print.
The paid dynamic tier — editable destinations, scan analytics, expiry, password gates, and multi-URL routing — is planned for after the static engine has traffic, and the redirect, tracking, and analytics guides below explain exactly what it will do and how it stays safe. Start with a free static code to prove the placement, and step up to dynamic only when editability or measurement is the actual lever.
Frequently asked questions
What is a QR code?
A QR code is a two-dimensional printed pattern of dark and light squares that stores a short piece of text — usually a URL — which a phone camera reads in one snapshot and turns into an action. The “QR” stands for Quick Response, and the format was invented in 1994 for tracking car parts. Our what is a QR code guide explains the basics, and the qr code history guide covers the origin story.
How does a QR code work?
A QR code works by encoding data as a grid of dark and light modules that the camera decodes locally: three corner finder patterns locate and orient the code, a data grid holds the text, Reed-Solomon error correction recovers damage, and eight masks break up confusing patterns. The phone never needs internet to read it. The how does a QR code work guide walks through every part of the code.
Are QR codes free?
Yes, in all three senses: the format is a royalty-free ISO standard (Denso Wave opened the patents in 1994), scanning is built into every modern phone at no cost, and generating a static code is free in your browser. The only thing that costs money is the dynamic tier, which needs a server for redirects and analytics. The are QR codes free guide has the full breakdown.
Do QR codes expire?
A static QR code never expires — the data is baked into the printed pattern, there is no clock, and it scans forever as long as the ink and the destination page survive. A dynamic QR code can expire if the redirect server goes down, the subscription lapses, or a scan-count or date limit is set. The do QR codes expire guide covers link rot in detail.
Can QR codes be tracked?
A static QR code cannot be tracked because the phone reads the pattern directly with no server in the scan path. A dynamic QR code can be tracked, because every scan passes through a redirect server that logs each request — giving you scan count, approximate location, device, and time of day. The qr code tracking and qr code analytics guides explain the full stack.
Are QR codes safe?
A QR code itself cannot give your phone a virus — it is just printed text the camera reads; the risk is the destination a URL code sends you to, exactly like a link in an email, and this QR-guided phishing has its own name: quishing. Always read the URL preview banner before tapping, and treat codes on untrusted surfaces like unexpected links. The qr code security guide covers the scams and defenses.
What is the difference between static and dynamic QR codes?
A static QR code encodes its data directly into the printed pattern — free, private, immortal, but uneditable without reprinting. A dynamic QR code stores only a short redirect link and looks the real destination up on a server — editable, trackable, and expirable, but dependent on that server staying alive. The static vs dynamic QR guide and the dynamic QR code guide cover the full trade-off.
How big should a QR code be?
Size the code for the scan distance using the 1/10 rule: the code width should be about one-tenth of the distance people will scan from, so a 10cm code works up to about 1 metre away. Bigger is always safer, and data density (long payloads) forces a denser grid that needs to be larger to scan. The qr code size guide has a use-case table with minimum sizes.
What colors can a QR code be?
Almost any color works as long as the dark modules stay clearly darker than the light background — the hard rule is contrast, roughly a 4:1 luminance ratio, with dark-on-light as the reliable baseline. Inverted light-on-dark, mid-tone greys, and gradients that dip into light tones are the common failure modes. The qr code colors guide has the do-and-don’t table.
Can I add a logo to a QR code?
Yes — set error correction to level H, keep the logo about 20–22% of the code width, center it, and never let it cover the three corner finder eyes. Level H reserves about 30% redundancy so the code survives the covered data, but it also makes the grid denser, so keep the payload short. The qr code with logo guide covers the full recipe.
How do I fix a QR code that won’t scan?
A QR that won’t scan is almost always one of a small set of fixable mistakes: quiet zone too small, low contrast, logo too big for level H, print too small for the scan distance, a glossy or curved surface, data too dense, or — for a dynamic code — a rotted redirect. Work through the checklist and change one variable at a time. The common QR code mistakes guide is the full troubleshooting table.
How do I test a QR code before printing?
Run a four-layer pass: scan on at least two phones of different ages, print one sample at the final size and scan from the real distance, check contrast and the four-module quiet zone, and decode the final image back to text to confirm it round-trips to exactly what you intended. QRForge’s free decode helper does that last check in your browser. The qr code validation guide walks through the full checklist.
What can a QR code store?
Under the hood a QR code stores plain text, but phones ship recognizers for standard text formats: URLs, plain text, WiFi credentials, vCards, SMS, emails, and calendar events. Pick the most specific type for the action you want so the phone turns it into one tap. The qr code content types guide lists all seven types and what each does.
How many characters can a QR code hold?
At the largest size (version 40, error correction level L) a QR code holds up to 7,089 digits, 4,296 alphanumeric characters, 2,953 bytes, or 1,817 kanji. Real capacity depends on the encoding mode, the version, and the error-correction level, and the practical limit is scannability not the headline maximum. The how many characters can a QR code hold guide has the full capacity table.
How do I print a QR code?
Use a vector format (SVG or EPS) or a 300+dpi raster at the final printed size, set error correction to level H, keep at least a four-module quiet zone clear, print dark-on-light on matte stock, and proof-test one copy before the full run. Never scale a small PNG up, because it adds no detail and softens the module edges. The qr code printing guide is the full print checklist.
What is error correction and which level should I use?
Error correction uses Reed-Solomon redundancy so a damaged or partially covered code still scans; there are four levels — L (7%), M (15%), Q (25%), H (30%). Use M by default, H whenever you add a logo or the code will take wear, and L only when you need maximum capacity and the code will stay clean. The qr error correction guide explains the trade-off.
Can a QR code link to a different URL or be edited?
A static QR code cannot — the destination is baked into the ink and you reprint to change it. A dynamic QR code can, because it stores only a short redirect link whose real destination lives on a server you control; edit the server mapping and the same printed code goes somewhere new. The qr code redirect guide explains the redirect mechanic in detail.
How do I scan a QR code?
Open the built-in Camera app, point it at the code, and tap the URL banner that appears — on iPhone this has worked natively since iOS 11, and on Android via the Camera or Google Lens. You do not need a dedicated scanner app on any modern phone. The how to scan a QR code guide covers iPhone, Android, and what to do when it won’t scan.
Are QR codes accessible?
On its own a bare QR code is a visual-only affordance a screen reader cannot use, because the data is an optical pattern with no text layer; the fix is never the code itself but what you put next to it — pair every code with an equivalent text link or short URL to the same destination. The qr code accessibility guide covers the WCAG angle and the mitigations.