# PY01004: Invalid Card Number

## What This Means[​](#what-this-means "Direct link to What This Means")

The card number entered is not valid. Card numbers follow specific patterns and include check digits for validation.

## Common Causes[​](#common-causes "Direct link to Common Causes")

* **Typo** — One or more digits entered incorrectly
* **Missing digits** — Not all digits were entered
* **Extra digits** — Too many digits entered
* **Wrong card** — Different card number than physical card
* **Card reader error** — Chip/swipe read the wrong data

## How to Fix[​](#how-to-fix "Direct link to How to Fix")

### 1. Re-enter the Card Number[​](#1-re-enter-the-card-number "Direct link to 1. Re-enter the Card Number")

Carefully enter all digits:

* Check the physical card
* Enter each digit slowly
* Verify the full number before submitting

### 2. Check Card Type[​](#2-check-card-type "Direct link to 2. Check Card Type")

Ensure the card type is supported:

* Visa (starts with 4)
* Mastercard (starts with 51-55 or 22-27)
* Amex (starts with 34 or 37)
* Discover (starts with 6011, 622, 644-649, 65)

### 3. Try Again with Card Reader[​](#3-try-again-with-card-reader "Direct link to 3. Try Again with Card Reader")

If using a chip/swipe reader:

* Clean the card chip
* Try a different read method (chip vs swipe)
* Manually enter if reader fails

### 4. Use a Different Card[​](#4-use-a-different-card "Direct link to 4. Use a Different Card")

If the card number continues to fail:

* The card may be damaged
* Try a different card
* Use an alternative payment method

### 5. Check for Card Damage[​](#5-check-for-card-damage "Direct link to 5. Check for Card Damage")

Physical card issues:

* Scratched magnetic stripe
* Damaged chip
* Worn or faded numbers
* Card may need replacement

## Card Number Formats[​](#card-number-formats "Direct link to Card Number Formats")

| Card Type  | Length | Starts With            |
| ---------- | ------ | ---------------------- |
| Visa       | 16     | 4                      |
| Mastercard | 16     | 51-55, 22-27           |
| Amex       | 15     | 34, 37                 |
| Discover   | 16     | 6011, 622, 644-649, 65 |

## Related Errors[​](#related-errors "Direct link to Related Errors")

* [PY01001](/error-codes/PY01001.md) — Payment Declined
* [PY01003](/error-codes/PY01003.md) — Card Expired