Is the revision comparison free?

Yes, completely free and open source (Apache-2.0), with no page limits or account.

Are my drawings uploaded to compare them?

No. Both PDFs are rendered and blended locally in your browser; nothing is sent anywhere.

How does the colour coding work?

Ink that exists only in revision A shows red (removed in the newer drawing), ink only in revision B shows blue (added), and matching linework blends to dark.

Can it compare sheets of different paper sizes?

Yes. With Fit B to A enabled, revision B is scaled onto revision A's page box before blending; fine alignment is done with the nudge buttons.

Free & open source · files never uploaded

Compare two drawing revisions, free, right in your browser

pdf2takeoff overlays two revisions of any PDF drawing and colour-codes the difference: red was removed, blue was added, and unchanged linework stays dark. Both files are rendered on your own machine; nothing is uploaded, and it works with scanned or vector sheets from any CAD tool.

Free, no account Files never uploaded Open source · Apache-2.0 Works offline once loaded

Compare your drawings now →

How to compare revisions

Open revision A. Open the current drawing in pdf2takeoff and click Compare; the open file becomes revision A.
Choose revision B. Pick the newer sheet; the overlay blend appears instantly.
Read the colours. Red exists only in A (deleted in the new revision); blue exists only in B (new); dark ink is unchanged.
Align. Fit B to A scales B onto A's page size automatically; the nudge arrows fine-tune alignment to the millimetre.
Isolate the changes. Turn on Changes only to fade everything unchanged to grey.

Why estimators and reviewers use it

Issued-for-construction sets churn constantly, and a missed revision can cost a variation claim or a rebuild. An overlay compare turns a half-hour of squinting at two windows into a five-second colour-coded answer: what moved, what was added, what was deleted, including moved walls (old position in red, new position in blue), added or removed fixtures, and changed dimensions.

FAQ

Is it free?

Yes: free, Apache-2.0 licensed open source, no limits and no account.

Are my drawings private?

Yes. The comparison runs 100% in your browser; your PDFs never leave your machine.

Does it work with scanned drawings?

Yes. The blend works on rendered pixels, so scanned sheets compare just as well as vector CAD plots.

Can I measure on the compared result?

Compare and takeoff are one tool: exit compare and your calibrated measurements are still there, on either revision.