# Gerber Viewer

> Loft Gerber Viewer is a free online Gerber and Excellon PCB viewer that opens RS-274X, Gerber X2, and Excellon drill files in your browser without any upload, install, or signup. Drop the fab .zip from KiCad, Altium Designer, EAGLE, or any PCB CAD tool — the viewer auto-detects layer roles, lets you toggle and reorder layers, snap-to-pad measure in millimetres at native resolution, pin trace widths as persistent annotations, highlight every flash of a chosen D-code aperture, and run DRC checks against fab-house presets. Renders in WebGL. The viewport and visible-layer state encode into a URL fragment so views are shareable. Files never leave your device.


Live tool: https://lofttools.com/tools/open-tools/gerber-viewer

Category: Open Anything


## What it does

- RS-274X parser with full Gerber X2 attribute support
- Excellon and XNC drill files auto-detected
- .zip / .tar / .tar.gz / .tgz archive auto-extract
- Loose .gbr / .drl / .gtl / .gbl / .gts / .gbs / .gko / .gm1 files accepted
- Per-layer toggle, reorder, color, and opacity controls
- Snap-to-pad measurement at the file's native coordinate resolution (typically 0.1 µm)
- Trace-width probe shows the conductor width under the cursor — click any trace in inspect mode to pin a persistent dimension annotation
- Aperture highlight — click any D-code row in the aperture table to glow every flash of that tool on the selected layer
- DRC checks with preset rule packs (fab-standard, hobbyist, JLCPCB / PCBWay) and per-rule overrides; violations group into an error explorer that recenters the viewport on click
- X2 netlist surfaced from %TO.N attributes — click a net to highlight every connected pad and stroke across copper layers
- WebGL renderer with stencil-based polarity for clean overlapping fills
- Viewport, layer visibility, color, and opacity encode into the URL fragment for sharing
- PNG, SVG, and DXF export
- Soldermask, silkscreen, copper, paste, drill, and outline layers rendered with realistic colors
- Bottom-side default-hidden until toggled (avoids overlap clutter on first load)
- Flex / rigid-flex board detection with stackup pane (auto bend-radius math per IPC-2223)
- Aperture macro support including primitive 7 (thermal) edge cases
- Pick-and-place CSV overlay (KiCad .pos, JLCPCB CPL, Altium PnP auto-detected)
- Drag-and-drop or file-picker input
- Works offline after the first visit (PWA cache)

## How it works

1. **Drop your fab archive** — Drag a .zip / .tar / .tar.gz of your fab output, or loose .gbr / .drl files. The viewer detects which layer is which automatically.
2. **Toggle layers** — Click any layer in the side panel to show or hide. Reorder for diff inspection. Adjust per-layer color and opacity.
3. **Measure** — Switch to measure mode. Click two points — distance snaps to pad centers and trace centerlines. Trace-width probe shows the conductor width under the cursor.
4. **Share or export** — Copy the URL — viewport and visible layers are encoded in the fragment. Or export PNG / SVG / DXF.

## FAQ

### What Gerber formats does this support?

RS-274X (extended Gerber) and Gerber X2 attributes. Excellon and XNC drill files are auto-detected. Older RS-274D (no embedded apertures) is not supported.

### What archive formats can I drop?

.zip, .tar, .tar.gz, and .tgz. Loose .gbr / .drl / .gtl / .gbl files are also accepted.

### Can it open ODB++ or IPC-2581?

Not yet. Gerber RS-274X / X2 plus Excellon are the MVP. ODB++ and IPC-2581 are on the roadmap.

### How accurate are the measurements?

Distances are computed in the file's native coordinate system (typically millimeters at 0.1 µm resolution). Pad-center snap is geometric (centroid of the aperture flash).

### Is Gerber a trademark?

Yes — Gerber is a registered trademark of Ucamco NV. Loft Tools is an independent third-party viewer and is not affiliated with or endorsed by Ucamco.

## Tips

- **Drop the whole ZIP** — Loft auto-detects layer naming from Eagle, KiCad, Altium, and Pads. No need to rename or sort files first.
- **Snap-to-pad measurement** — Hold Shift while dragging the ruler to snap endpoints to pad centers. Trace-width probe works at any zoom past 4000%.
- **Snapshot URLs capture view state** — Right-click → Copy view URL. The link captures rotation, zoom, layer visibility, and any active measurement — paste it in Slack to share the exact view.
- **Runs without installing CAM350** — Whole viewer is browser-based. No license, no install, works on Mac, Windows, Linux, and even on your phone.

## How Loft Gerber Viewer compares

| Tool | Install needed | Files uploaded | RS-274X | Excellon | Measurement | URL snapshot | Cost |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Loft Gerber Viewer | No | No (in-browser) | Yes (X2 attrs) | Yes | Snap-to-pad | Yes | Free |
| gerbv (Linux native) | Yes | N/A | Yes | Yes | Limited | No | Free |
| KiCad GerbView | Yes (KiCad install) | N/A | Yes | Yes | Yes | No | Free |
| online-gerber-viewer.com | No | Yes (server upload) | Yes | Yes | No | No | Free |
| Tracespace | No | Yes (server upload) | Yes | Yes | No | No | Free |
| ZofzPCB (3D) | Yes (Windows) | N/A | Yes | Yes | No | No | Free |

_Verified 2026-05. Native PCB CAD suites (Altium, EAGLE, Mentor) are not listed — they include their own Gerber inspector but require a paid licence to launch.
_

## Privacy — what we do not do

This tool runs entirely in the browser via WebAssembly. Your file never reaches a Loft Tools server. Specifically:

- **No upload.** The file bytes load into the browser tab's memory and process on your own CPU. Open DevTools → Network and observe zero outbound requests carrying file data while Gerber Viewer runs.
- **No AI training on your file.** Loft does not train models. We could not train on a file we cannot see.
- **No content scanning.** No virus, copyright, or content-moderation pass against your file. The bytes are not accessible to us.
- **No server-side log of file contents, filenames, or EXIF metadata.** Cloudflare edge captures URL and truncated IP for abuse defense (standard CDN behaviour). Cloudflare Web Analytics records anonymous page hits, no cookies, no PII. Nothing about your file content reaches any log.
- **No retention.** Close the tab and the file leaves browser memory. No backups exist on our side because no copy ever existed on our side.
- **No account.** No email, no signup, no auth, no telemetry tied to you.
- **Offline-capable after first visit** (PWA). Once you've loaded a tool, it caches; later sessions work without internet. For high-sensitivity files, run the tool once online to warm the cache, then disconnect before processing.

Compare with upload-based services: each transmits your file to a processing server. Even over HTTPS, each has logs, retention windows, and subpoena exposure. Loft has none of these because the server architecture does not include your file.

## More

- All tools: https://lofttools.com/tools
- Category: https://lofttools.com/tools/open-tools
- LLM index: https://lofttools.com/llms.txt