# UPI QR codes — the NPCI spec, field by field

> A UPI QR code stores a upi://pay deep link containing the payee's VPA, name and optionally an amount. Any UPI app — GPay, PhonePe, Paytm, BHIM — reads the same format, because NPCI standardised it. Nothing is charged automatically; the payer confirms the amount and enters their PIN.

Source: https://useqr.app/upi-qr-code · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

---

## The payload

```
upi://pay?pa=merchant@upi&pn=Chai%20Point&am=120.00&cu=INR&tn=Table%207
```

Every UPI app in India parses this, because the format is defined by NPCI rather than
by any one wallet. There is no per-app QR code — a single printed code works for
Google Pay, PhonePe, Paytm, BHIM, Amazon Pay and every bank app.

## Every parameter

| Param | Name | Required | Notes |
|---|---|---|---|
| `pa` | Payee address (VPA) | **yes** | `name@bank`, e.g. `merchant@okhdfcbank` |
| `pn` | Payee name | **yes** | Shown to the payer before they confirm |
| `am` | Amount | no | Two decimal places, e.g. `120.00` |
| `cu` | Currency | effectively yes | Always `INR` |
| `tn` | Transaction note | no | Shown to the payer; keep it short |
| `tr` | Transaction reference | no | Your order id, 1–35 alphanumeric |
| `mc` | Merchant category code | no | 4-digit ISO 18245 |
| `mode` | Mode | no | `02` for merchant-presented static QR |
| `sign` | Signature | no | Only for signed merchant codes issued by a PSP |

UseQR validates the VPA against `^[\w.-]{2,256}@[a-zA-Z]{2,64}$`, the amount to two
decimals, the MCC to exactly four digits, and the reference to 35 alphanumeric
characters — the constraints the NPCI spec actually imposes, so a code that generates
here will not be silently rejected at the app.

## Static versus dynamic, in UPI terms

- **Static**: no `am`. The payer types the amount. This is the shop-counter standee —
  print once, use forever, no per-transaction cost.
- **Dynamic**: `am` is set. Generated per transaction, usually shown on a screen. Best
  for billed amounts where typing errors matter.

A printed code with a fixed amount is almost always a mistake — prices change, and the
code cannot.

## Merchant category codes

`mc` matters more than it looks. Some issuers apply different interchange, limits or
cashback rules by MCC, and a few UPI-Lite and offline-payment flows are gated on it.
Common values: `5411` grocery, `5812` restaurants, `5814` fast food, `5912` pharmacy,
`8220` education, `4121` taxi. If you have a PSP-issued merchant VPA, use the MCC they
assigned rather than picking one.

## Why an app sometimes will not detect the code

In rough order of frequency:

1. **The code is too small or too dense for the counter distance.** A standee scanned
   from 40 cm needs at least 4 cm of code; most printed UPI standees are undersized.
2. **The VPA has a typo.** Apps validate the handle against a live registry — a wrong
   bank handle fails at confirmation, not at scan.
3. **A long `tn` pushed the version up.** Keep the note under 25 characters.
4. **The code was resized in a design tool with smoothing on**, blurring module edges.
5. **Glare.** Glossy lamination on a counter standee under a ceiling light is the
   classic real-world failure. Use matt.

## Print guidance for a shop counter

- Minimum **4 cm × 4 cm** of code, not counting the frame, for a 40 cm scan distance.
- Error correction **M** is enough; go to **Q** only if you are adding a logo.
- Matt laminate, never gloss.
- Keep the printed VPA and business name next to the code — it lets a customer pay
  manually when their camera struggles, and it is a fraud check.

## Fraud: the sticker-over-sticker problem

The dominant UPI QR fraud is physical, not digital: someone pastes their own code over
yours. Two defences that cost nothing — print the payee name large enough that a
customer notices when the app shows a different one, and check your standee daily.
No amount of cryptography helps if the customer never reads the confirmation screen.

## FAQ

### Do I need a different QR code for Google Pay, PhonePe and Paytm?
No. NPCI standardised the format, so one upi://pay code works in every UPI app including all bank apps. Any service selling you per-app codes is selling you nothing.

### Should my printed shop code include the amount?
No. Leave the amount out for a printed code so the customer enters it. A fixed printed amount cannot be changed when prices do.

### Is there a fee for using a UPI QR code?
Person-to-person UPI is free. Merchant transactions may carry charges depending on your PSP agreement and the instrument used; generating and printing the code costs nothing.

### How big should a UPI QR standee be?
At least 4 cm of code for a 40 cm scanning distance — roughly the width of a counter. Use the ten-to-one rule: printed width is at least the scan distance divided by ten.

### What is the mc parameter for?
The merchant category code, a four-digit ISO 18245 value. Some issuers apply different limits or rewards by category, and certain offline flows depend on it. Use the code your payment provider assigned.

### Can someone charge my account by making me scan a QR code?
No. A UPI QR code initiates a payment *from* the scanner, and it always requires their explicit confirmation and PIN. Any message telling you to scan a code "to receive money" is a scam.

## Try it

- https://useqr.app/upi
- https://useqr.app/size-calculator
- https://useqr.app/validate