Canonical: https://rom-weaver.com/docs/trim-roms-browser

# Trim a ROM in the browser

Use Trim to remove padding from a supported ROM and download a smaller copy. Keep the original for future patches.

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## Table of contents

- [Open Trim](<#open-trim>)
- [Save a trimmed copy](<#save-a-trimmed-copy>)
- [Restore padding](<#restore-padding>)

<!-- END doctoc -->

## Open Trim

1. Enable **Beta tools** in [Settings](<https://rom-weaver.com/docs/browser-settings.md#enable-beta-tools>).
2. Open [Trim](<https://rom-weaver.com/trim-rom>).
3. Add the ROM or its archive.
4. Select the required member if an archive contains several candidates.
5. Wait for reading, checksumming, and identification to finish.

The [trim support reference](<https://rom-weaver.com/docs/supported-formats.md#trim-support>) lists supported formats and restoration limits.

## Save a trimmed copy

1. Check the selected file in the ROM card. Open **Checks** to record its original checksums.
2. Choose an output name and format.
3. Select **TRIM & DOWNLOAD**.
4. Read the warning, then select **Trim ROM** to continue.
5. Save the result and test it in the emulator or hardware you use.

A file without removable padding may have no useful size reduction. A format that is not supported cannot be made trimmable by renaming it.

## Restore padding

The browser does not expose the CLI's restore-padding or revert-marker options. Use [Trim and restore from the CLI](<https://rom-weaver.com/docs/cli-trim.md#put-the-padding-back>) when you need them.

Restoring padding does not always reproduce the original bytes. XISO and RVZ scrub cannot be reverted. [Compression and trimming](<https://rom-weaver.com/docs/compression-formats.md#trim-compress-or-both>) explains the difference.