NFC FAQ

How does NFC work?

Data is transmitted between two NFC devices and/or tags when they come in close proximity to one another. There are three different types of NFC interactions:

Passive to Active

A passive NFC tag such as an NFC sticker is touched to an active NFC device such as an NFC-enabled phone.

Active to Passive

An active NFC device such as an NFC-enabled phone is touched to a passive NFC tag such as an NFC sticker

Active to Active

An active NFC device such as an NFC-enabled phone is touched to another active NFC device.

What is an NFC tag?

The term NFC tag is commonly used for a passive NFC tag. Examples of passive NFC tags are NFC inlays, NFC stickers, NFC wristbands and other converted NFC products. NFC tags are very similar to a USB stick, except that they don’t have to be plugged into a PC to transfer data. There is no battery inside of NFC tags. They all have an integrated circuit (IC) and antennae inside of them. Data is transferred via this antennae.

Which NFC chip should I use?

The chip type that works best for you is often determined by what you want to write to the NFC tag (i.e. how much data you need).  NFC tag data is measured in bytes. The chip type and data size for each product at BUYNFCTAGS.COM is listed in the details section for that product.

Best Practices
  • Choose the chip with the smallest amount of memory that meets your data requirements. You should try to put as little data on the NFC chip as possible. The more data on the chip the slower it will be to read and write.
  • Choose the fastest chip possible. Users have an expectation that an NFC interaction is just a quick touch (< 0.5s). However some of these NFC chips (1ks..) take much longer.
  • Choose the largest NFC inlay you can. The larger the NFC inlay, the further the reading distance.
  • Choose an NFC chip that is compatible with the devices that will interact with it; some NFC chips are not compatible with all devices. Choosing an NFC Forum complaint chip is a good idea.
  • Some NFC chips have specialized features (one-time-programmable, security, …). Often these features effect performance and cost; make sure you understand what each chip offers.
  • Use the cheapest NFC chip you can!

Do I need an app or software to use NFC?

Unlike QR Codes, you do not have to download an app to use NFC. All you have to do is make sure that the NFC functionality is turned on in your mobile phone. This option is usually found in the phone Settings. If NFC is turned on in your NFC phone, NFC will be on in the background. That means if you touch your NFC phone to an NFC tag, the data transfer will occur without you having to do any extra steps. The user experience is different for each device and many devices will request your permission before opening the data from the NFC tag.

How much data can an NFC chip store?

The amount of data an NFC tag can contain is determined by the NFC chip type.

What distance can an NFC tag be read from?

NFC is restricted to a very small reading range, that is why it is called Near Field Communication. The two NFC devices and/or tags will need to be within around 1 to 2 centimeters of each other in order to exchange data, they basically have to touch.

The specific reading range will vary depending on a variety of factors such as the size of the NFC tag or the type of NFC reader being used. If you are looking for a technology that communicates at a greater distance, you’re likely searching for UHF or RFID.

What Determines the NFC Tag Reading Distance
  • Size and shape of the NFC tag – In general, the larger the tag the better the reading range. This is because larger NFC tags will have a larger antennae.
  • The environment the NFC tag is placed in – Environmental hazards such as metal or aluminum will decrease or inhibit the NFC tag’s performance.
  • The NFC tag form factor – The more material that is in between the NFC tag’s antennae and the NFC reader, the lower the NFC tag’s performance. For example, a converted product such as a silicone wristband will have a shorter reading distance than a raw NFC inlay.
  • The type of NFC reader that is being used – In general, USB or Serial port connected NFC readers will have a greater reading range than an NFC-enabled phone or tablet.
  • NFC chip type – There are some high-performance NFC chip types that can be quite small and still have an excellent reading range.

Can an NFC chip be rewritten?

Most NFC chip types are read/writable which means that the data written on the NFC tag can be erased and written to again. This means that anyone with an NFC-enabled device could erase your data unless you choose to lock the NFC tag so it is read-only. When an NFC tag is locked, the data cannot be erased. Locking a tag is a permanent action and cannot be undone.

What is an NFC device?

The term NFC device is commonly used for an active NFC tag. Examples of active NFC devices are NFC-enabled phones, NFC-enabled tablets and PC-linked NFC readers. These devices are powered either by an internal battery or are connected to a PC via a USB or Serial port. They all have an NFC reader inside of them.

Can an NFC chip be encrypted?

NDEF record encryption is not a feature built in to NFC. The only way this could be accomplished is through the creation of a custom MimeType record. This record would need to have the cipher data written in the payload and the application reading the NFC tag would have the decryption key; all other applications would ignore this record.

Can a UID be rewritten?

The Unique Identifier (UID) on an NFC tag cannot be rewritten. This identifier is stored on a locked portion of the NFC chip, as being able to rewrite it would defeat the purpose of being able to identify a distinct NFC tag.

Which NFC chip can store a contact record?

The NTAG203 NFC chip type is a widely used NFC chip that has 144 usable bytes for user memory. This would not be enough data to store a full contact card or vcard. It would only be enough room for a short contact. If you need enough room to store a full contact card, you will need to use the Mifare 1K chip type.

Examples of a Short Contact
  • first name, last name, and email address
  • first name, last name, company name, phone number
Example of a Full Contact
  • full name, multiple emails, multiple phones, address, company, title…

The NTAG203 is compatible with all NFC devices but only has 144 bytes of memory. The Mifare 1K has 752 bytes of memory, but is not compatible with some Android, some Windows, and Blackberry devices. If you are looking for an NFC chip type with high-data capacity that is still compatible with most devices, you may want to consider the NXP NTAG16 or the Topaz 512 NFC chip types.

What Is The NFC Forum?

The Near Field Communication Forum was formed to advance the use of Near Field Communication technology by developing specifications, ensuring interoperability among devices and services, and educating the market about NFC technology.

The NFC Forum has mandated four tag types to be operable with NFC devices. This is the backbone of interoperability between different NFC tag providers and NFC device manufacturers to ensure a consistent user experience.

This means that if an NFC tag is NFC Forum Type 1, Type 2, Type 3 or Type 4, it complies to the NFC Forum specifications. NFC Forum compliant NFC tags typically have less compatibility issues than non-NFC Forum certified NFC tags such as the Mifare Classic.