Compare Construction Plan Revisions PDF to PDF
On a construction project, drawing revisions arrive constantly — RFI responses, change orders, supplemental instructions. DrawDiff shows you exactly what changed between any two issued PDFs in seconds, without uploading them anywhere.
The Cost of Missing a Change
In construction, an undetected drawing revision can mean built work that doesn't match the design, costly rework, contractual disputes, and programme delays. The larger and more complex the project, the more drawings are in circulation, and the higher the risk of a change slipping through.
Manual comparison — printing and overlaying sheets on a light table, or scrolling back and forth between PDFs — is slow and unreliable. DrawDiff makes it fast and pixel-accurate.
Common Scenarios on a Construction Project
- Issued For Construction revisions — compare the new issue against the previous to document every change before distributing to site
- RFI responses — check what was actually changed in the sketch or revised drawing issued with the RFI answer
- Change order drawings — verify the scope of a change before pricing or agreeing to it
- Shop drawing approval — compare a contractor's resubmission against the previous version and against the specification drawing
- Coordination drawings — overlay MEP, structural, and architectural to identify clashes
- Snagging and as-built — compare as-built drawings against design intent
How to Compare Construction Plans with DrawDiff
Load both PDFs
Drag the original drawing onto the Original zone and the revised drawing onto the Revised zone. Multi-page drawing packages are supported — all sheets are compared in order.
Run Compare
Click ▶ Run Compare. DrawDiff renders both PDFs at high resolution and produces a colour-coded overlay: green for what was removed, red for what was added, cyan for what's unchanged.
Find and number the differences
Click ◎ Find Differences to automatically detect and number every changed region on the sheet. Jump to any difference, toggle boxes and numbers, and export a JPG with the numbered overlay for your change log.
Export
Save individual redlined sheets as JPGs, or export the full set as a single PDF. Use the filename prefix field to match your drawing numbering system.
Multi-Page Drawing Package Support
Load a complete drawing package as a single PDF and DrawDiff compares every sheet in one run — Sheet 01 vs Sheet 01, Sheet 02 vs Sheet 02, and so on. Navigate page by page with the arrow keys or page selector. The status bar shows pixel-level statistics for each sheet.
When Views Have Shifted Between Issues
Sometimes a drawing is re-detailed between revisions, shifting the position or scale of a view. The Alignment Tool lets you select a region and pick a reference point on each drawing to align them before comparing. DrawDiff also detects written scale annotations (SCALE 1:50, 1:100, etc.) and compensates automatically.
Free to use. No login. Your drawings stay on your device.
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