Acx’s File Format and Delivery Requirements: What Every Narrator Should Know

March 16, 2026

By: Audio Scene

For narrators working with ACX (Audiobook Creation Exchange), understanding the platform’s file format and delivery requirements is essential to ensure your audiobook is accepted and published smoothly. Proper preparation can save you time and prevent delays in the production process.

ACX’s Accepted File Formats

ACX requires audiobook files to be in a specific format to maintain quality and compatibility. The primary accepted format is:

  • WAV (Waveform Audio File Format) – uncompressed, high-quality audio
  • FLAC (Free Lossless Audio Codec) – lossless compression, acceptable if specified

However, the most common and recommended format for submission is WAV, with specifications including:

  • Sample rate: 44.1 kHz
  • Bit depth: 16-bit or higher
  • Channels: Stereo (2 channels)
  • File size: Not exceeding 2 GB per file

File Naming and Organization

Proper file naming and organization are crucial for smooth processing. Follow these guidelines:

  • Use clear, consistent naming conventions, e.g., “Chapter01_William”.
  • Number chapters sequentially to maintain order.
  • Avoid special characters or spaces in filenames.

Delivery Requirements

When submitting your files, ensure they meet ACX’s delivery standards:

  • Upload files via the ACX portal or connected tools like Audiobook Creator.
  • Include a properly formatted audiobook cover image (minimum 2400 x 2400 pixels, JPEG or PNG).
  • Provide accurate metadata, including title, author, and narrator information.
  • Ensure all files are free of background noise, distortions, or errors.

Quality Control and Final Checks

Before submission, perform the following checks:

  • Listen to each file to confirm clarity and consistency.
  • Check for proper pacing and pronunciation.
  • Ensure no accidental background sounds or interruptions.
  • Verify filenames and metadata match the project details.

Adhering to ACX’s file format and delivery requirements helps ensure your audiobook is accepted without delays, allowing your work to reach eager listeners faster. Proper preparation reflects professionalism and respect for the platform’s standards.