RFID FAQ - 40 Questions Answered

These are the questions we are asked most often by people starting out with RFID - from students and engineers to warehouse managers and business owners. Each answer is deliberately short; follow the links for the full explanation.

RFID basics

What is RFID?

RFID (Radio Frequency Identification) is a way of identifying objects, people or animals automatically using radio waves. A small tag carrying a chip and antenna is attached to the item, and a reader communicates with it wirelessly to read its identity and, sometimes, extra data. For a full introduction see What is RFID?.

How does RFID work?

The reader transmits radio energy through its antenna. A passive tag in range harvests that energy to power its chip and replies - by load modulation at LF and HF, or by backscatter (reflecting a modulated signal) at UHF. The reader decodes the reply and passes the tag data to software, which links the ID to a product, asset or person. The step-by-step physics is in How RFID Works.

What is the difference between RFID and a barcode?

A barcode must be seen by a scanner, one at a time, and usually identifies only the product type. RFID needs no line of sight, can read many tags at once, can identify each individual item with a unique serial number, and some tags can be rewritten. Barcodes are cheaper per label, so many businesses use both together on the same label.

Does RFID need line of sight?

No. Radio waves pass through cardboard, plastic, wood, fabric and paper, so tags can be read inside cartons or behind covers. However, metal blocks and reflects radio waves and water absorbs UHF energy, so placement still matters.

Is NFC the same as RFID?

NFC (Near Field Communication) is a branch of HF RFID at 13.56 MHz, designed for deliberate, very short-range interactions of a few centimetres - tapping a phone or card. All NFC is RFID, but most RFID is not NFC: UHF RFID, for example, reads over metres and cannot be read by a normal phone.

What frequencies does RFID use?

The main bands are LF (125-134 kHz), HF (13.56 MHz, including NFC), UHF (860-960 MHz, of which India uses 865-867 MHz) and microwave (2.45 GHz and higher, mainly for active systems). Each band has a different balance of range, speed and tolerance to water and metal.

Tags and chips

What is the difference between passive and active RFID tags?

Passive tags have no battery and are powered by the reader, so they are small, cheap and last for years, with ranges from centimetres to around 10 metres. Active tags contain a battery and transmitter, giving ranges of tens to hundreds of metres but at higher cost, larger size and limited battery life. Battery-assisted passive (BAP) tags sit in between.

What is an RFID inlay?

An inlay is the working heart of a tag: a tiny chip bonded to a printed or etched antenna on a thin plastic film. Inlays are converted into labels, tickets, cards, wristbands or embedded inside hard tags. A "wet" inlay has adhesive; a "dry" inlay does not.

Do RFID tags work on metal and liquids?

Standard UHF labels perform poorly directly on metal and on water-rich items, because metal detunes and reflects the signal and water absorbs it. Purpose-built on-metal tags, tags tuned for liquids, and LF or HF technology solve these problems. Always test the actual tag on the actual item.

How much data can an RFID tag store?

Most UHF tags store a 96- or 128-bit EPC identifier, plus a factory-locked TID and optional user memory ranging from none to a few kilobits. HF and NFC chips typically hold from under a hundred bytes to several kilobytes. RFID tags are best used to carry an identity, with detailed data kept in a database.

Can RFID tags be rewritten?

Most passive tags are rewritable - the EPC and user memory can be changed many thousands of times. Memory can also be locked with a password or permanently locked so it can never be changed, which is common for item identifiers. The TID or UID set by the chip maker cannot be altered.

How long do RFID tags last?

Passive tags have no battery, so their life is limited mainly by physical wear and the chip's data retention, which is typically specified at 10 years or more. Active tags last as long as their battery, typically a few years depending on how often they transmit.

Readers and read range

How far can RFID be read?

Typical ranges are: LF up to a few tens of centimetres, HF from a few centimetres to about a metre (NFC is intentionally just a few centimetres), passive UHF several metres - often up to 8-12 m with a good fixed reader and tag in favourable conditions - and active RFID 100 m or more. See RFID Read Range & Performance.

Why does read range vary so much?

Range depends on reader power, antenna gain and polarisation, cable loss, tag size and chip sensitivity, tag orientation, the material the tag is attached to, nearby metal and liquids, and reflections in the room. A tag that reads at 10 m in open air may read at 2 m on a water bottle.

Should I choose a fixed or handheld reader?

Fixed readers are mounted at doors, conveyors, gates or shelves and read automatically as items pass - ideal for continuous tracking. Handheld readers are carried by staff for stock counts, searches and occasional audits. Many projects use both: fixed readers for movement, handhelds for counting.

Can a reader read many tags at the same time?

Yes. Anti-collision protocols let a passive UHF reader read hundreds of tags per second, so a full carton or trolley can be counted in seconds. HF readers also handle multiple tags, but much more slowly; NFC is designed for one tag at a time.

Can my smartphone read RFID tags?

Most smartphones have NFC and can read NFC tags and many 13.56 MHz HF cards and labels. Phones cannot read UHF tags or LF tags; for UHF you need a dedicated handheld reader or a UHF "sled" accessory that attaches to the phone.

How powerful are RFID readers in India?

UHF readers used in India operate in 865-867 MHz with radiated power up to 4 W EIRP permitted by WPC. Handheld readers usually transmit at lower power than fixed readers. The power level should be set during installation - more power is not always better, as it can cause stray reads.

Cost and ROI

How much does an RFID tag cost in India?

Indicative prices: plain UHF labels in volume from a few rupees to around Rs 15 each; NFC stickers and HF cards somewhat more; UHF on-metal and rugged hard tags from about Rs 50 to several hundred rupees each. Exact prices depend on chip, size, quantity, printing and packaging, so treat these only as a starting point.

How much does an RFID reader cost?

Indicatively, desktop and USB readers cost from a few thousand to a few tens of thousands of rupees; enterprise handheld UHF readers and fixed multi-port readers typically range from about Rs 1 lakh to Rs 3 lakh each; antennas, cables and mounts are extra. Prices vary widely with brand, features and import duties.

What does a complete RFID project cost?

Tags and readers are only part of it. A full budget includes antennas and installation, middleware or application software, integration with your ERP or WMS, label printers, testing, training and support. A small pilot can be done for a modest sum; a multi-site rollout is a capital project. See RFID Cost & ROI.

How do businesses get a return on RFID?

Typical benefits are faster stock counts, higher inventory accuracy, fewer lost or misplaced assets, fewer shipping errors, less manual data entry, reduced theft and better availability for customers. The strongest ROI comes from a clearly defined, measurable problem rather than tagging everything "because we can".

What is the cheapest way to start?

Start with a focused pilot: one process, one site, a few hundred to a few thousand tags, a handheld or one fixed read point, and simple software or an export to Excel. Measure the before-and-after numbers, then decide whether to scale.

Implementation

How do I start an RFID project?

Define the business problem and the numbers you want to improve; map the process; choose the items and read points; test tags on real items; run a pilot; integrate with your systems; then roll out in phases with training. The full roadmap is in RFID Implementation Step by Step.

Do I need to replace my existing software?

Usually not. RFID middleware or a small application collects and filters reads, then passes clean events to your existing ERP, WMS or asset system through an API, database or file interface. Some ERPs already have RFID modules.

What is an RFID site survey?

A site survey checks the real environment before installation: the layout, metal structures, existing RF noise, power and network points, and how tags read on your actual products at the planned read points. It prevents expensive surprises after go-live.

How accurate is RFID?

A well-designed system can achieve very high read accuracy, but no system reaches 100% by default. Accuracy depends on choosing the right tag, placing it well, configuring readers properly and designing the process. Measure accuracy during the pilot instead of relying on brochure claims.

Can I print and encode RFID labels myself?

Yes. RFID-enabled thermal printers print the text and barcode and encode the chip in a single pass, verifying each tag and rejecting faulty ones. Labelling software supplies the data, such as an SGTIN or an asset number.

How long does an RFID implementation take?

A simple pilot can run in a few weeks once tags and readers are chosen. A full multi-site rollout with integration typically takes a few months, mostly spent on process design, integration and testing rather than hardware installation.

Security and privacy

Can RFID tags be hacked or cloned?

Simple tags that only carry an ID can be read and copied by anyone with suitable equipment, so an ID alone is not proof of authenticity. Chips with cryptographic authentication, such as AES-based HF/NFC chips and Gen2v2 UHF chips, are much harder to clone. See RFID Security & Privacy.

Can someone read my card from a distance?

Payment and access cards are ISO 14443 proximity cards designed to work within a few centimetres, which makes long-distance skimming very difficult in practice. Payment cards also use cryptography for transactions. Shielded card sleeves add an extra layer if you are concerned.

Is RFID safe for health?

RFID readers emit low-power radio energy, regulated to stay within international exposure guidelines when installed correctly. Passive tags emit nothing on their own. As with other radio equipment, people with implanted medical devices should follow their doctor's and the manufacturer's guidance about prolonged close proximity to high-power antennas.

Does India's DPDP Act apply to RFID?

If RFID data can be linked to an identifiable person - for example employee badges, patient wristbands or student attendance - it is personal data and the Digital Personal Data Protection Act, 2023 applies. Collect only what you need, inform people, secure the data and set retention limits.

Can an RFID tag be switched off?

Yes. Gen2 UHF tags support a password-protected Kill command that permanently disables the tag, used for example when products leave a store. Tags can also be removed, or memory can be locked or partly hidden on chips that support it.

RFID in India

Which UHF frequency is used for RFID in India?

India uses 865-867 MHz for UHF RFID, with up to 4 W EIRP. Readers built for the US band (902-928 MHz) are not meant for use in India, so always buy equipment configured for the Indian band. Most modern tags work across 860-960 MHz and are fine to use.

Do I need a licence to use RFID in India?

The 865-867 MHz band is delicensed for RFID, so end users do not need an individual spectrum licence. The equipment itself should comply with WPC rules and carry Equipment Type Approval (ETA), which reputable suppliers and importers arrange.

How does FASTag work?

FASTag is a passive UHF RFID sticker on the vehicle windscreen that carries a unique ID linked to a prepaid wallet or bank account. As the vehicle approaches the toll lane, an overhead reader reads the tag and the toll is deducted electronically through the National Electronic Toll Collection (NETC) system. The tag is designed to break if removed, to prevent transfer between vehicles.

What role does GS1 India play in RFID?

GS1 India is the national body for GS1 standards. It allocates company prefixes, which are needed to create globally unique EPC codes such as SGTIN for products and SSCC for shipments, and promotes standards-based barcodes and RFID in Indian supply chains.

How do I choose an RFID supplier in India?

Look for a supplier that will test tags on your items before you buy, offers hardware for the Indian band with proper approvals, can integrate with your software, and provides local installation and support. Ask for references in a similar application and insist on a pilot before a large order.

How can I learn RFID properly?

Start with this free Academy, which takes you from fundamentals through tags, readers, standards, applications and implementation. Then practise with real hardware: read and write tags, test range on different materials and try a small project. For structured, hands-on training with certification, see the Certified RFID Specialist Program.