HID 37-Bit H10302 vs H10304: Practical Differences for Real-World Installs

When facilities upgrade or standardize their access control systems, one of the most common questions is how HID 37-bit H10302 cards compare to HID 37-bit H10304 cards. Both formats are widely used, but they differ in structure, compatibility, and how credentials are issued and managed in live environments. Whether you're supporting a legacy system or deploying a new access control platform, understanding these differences will help you avoid credential mismatches and integration issues.

Free samples to test are available: Contact us to request a free sample

What Are H10302 Cards?

The HID 37-bit H10302 format is one of the most commonly deployed 37-bit Wiegand structures in commercial access control. It’s frequently used in older HID proximity systems, mid-sized organizations, and corporate environments that prefer longer bit-lengths for improved card-number range.

Key Characteristics:

• 37-bit Wiegand structure
• Supports a large card number range for high-volume facilities
• Contains a facility code + card ID
• Broad compatibility with legacy HID Prox readers
• Commonly issued as white PVC cards, key fobs, and clamshell cards

For customers replacing existing H10302 credentials, matching the exact bit format is essential. Even a small deviation prevents proper reader-to-panel communication.

What Are H10304 Cards?

The HID 37-bit H10304 format is similar in bit length but uses a different internal encoding structure. While both formats are 37-bit Wiegand, the layout of the fields, parity, and card-number assignment varies enough that H10302 and H10304 are not interchangeable.

Key Characteristics:

• Also a 37-bit Wiegand format
• Different field layout than H10302
• Used primarily in specific large-scale corporate systems
• Often deployed in newer installations to expand numbering structures
• Requires explicit system support — many panels only accept one format at a time

If a system expects H10304 cards and you present an H10302 card, the panel typically interprets the credential incorrectly or rejects it entirely.

H10302 vs. H10304: Practical Differences Installers Should Know

1. Bit Layout & Field Structure

Both are 37-bit formats, but the internal bit positions within the frame differ. Because of this, one format cannot act as a substitute for the other without changing system settings.

2. Panel Compatibility

• Many access control panels must be configured for either H10302 or H10304 — not both.
• Some panels support both formats, but require separate card templates.
• Mixed-format environments often lead to credential-tracking errors.

3. Credential Programming

When ordering custom credentials (printed cards, fobs, or adhesive tokens), the card format must match exactly:

• 37-bit H10302 ≠ 37-bit H10304
• Facility codes and card ranges differ
• Encoding profiles must be selected correctly during production

This is an area where many facility managers make mistakes—especially when migrating from one format to another.

4. Real-World Installation Considerations

Installers frequently encounter the following challenges:

• Reader incompatibility: Some readers only support H10302.
• System migrations: Upgrading panels may require switching from H10302 to H10304 or vice versa.
• Credential tracking issues: Incorrect bit formats cause duplicated card numbers or “unknown credential” errors.
• Vendor mismatches: If a customer orders from the wrong supplier, credentials may not enroll properly.

Working with a supplier who specializes in credential formatting—like AuthorizID—helps avoid these costly issues.

How to Choose Between H10302 and H10304

Your decision should be based on:

• Existing system requirements
• Reader and panel compatibility
• Credential-volume needs
• Future expansion planning

If your system is already using H10302 cards, it is best to maintain that structure. If you’re designing a new deployment with high card volume and broader number assignments, H10304 may be advisable—assuming your platform supports it.

AuthorizID can help determine your system’s correct format and prevent encoding errors before you order cards.