FREE CHROME EXTENSION
bScaler
by Bury Associates
How often do you open a PDF drawing and wish there was an easy way to scale and measure from it? That's why we've created the perfect PDF measuring and mark-up tool for architects, engineers, surveyors and contractors. Scale, measure and mark up PDF drawings straight in Chrome - even when the drawing has no usable scale on screen.
What it does
You are often sent a PDF drawing whose title block says something like “1:200 at A1”. Printed at A1 that scale is correct, but on a computer screen the PDF is not A1 - so you can’t measure from it. bScaler fixes that.
Tell bScaler the sheet size and scale (or pick two points on a scale bar), and you can then measure real distances and areas straight off the PDF, mark them up, and export a tidy marked-up copy to share.
Download bScaler
Free to use. Runs entirely on your own computer - nothing is uploaded anywhere.
Install it in Chrome
A one-time setup that takes about a minute.
- Unzip the bScaler folder somewhere permanent, such as your Documents folder. (Don’t run it from inside the zip.)
- Open Chrome and go to
chrome://extensions(type it into the address bar). - Turn on Developer mode using the toggle in the top-right corner.
- Click Load unpacked and choose the bScaler folder (the one containing
manifest.json). - The bScaler “b” icon appears in your toolbar. Click it any time to open bScaler in a new tab. (Use the jigsaw 🧩 menu to pin it for quick access.)
Updating to a newer version? Replace the folder’s contents, then click the reload icon on the bScaler card in chrome://extensions.
How to use it
Four simple steps: open a drawing, set the scale, measure, and export.
📁1 · Open a PDF
Click Open, or simply drag a PDF anywhere onto the window.
📏2 · Set the scale
Click Scale and choose one of the two methods below. Do this each time you open a new drawing.
↘3 · Measure
Use Distance for lengths (single or running) and Area for polygons - the area is written inside.
⬇4 · Export
Click Export for a new marked-up PDF. Zoomed in? It asks whether to export the whole sheet or just your current view.
Setting the scale - two ways
By sheet size & scale
Pick the sheet the drawing was made for (A0-A4, US ANSI/ARCH, or custom) and the ratio (e.g. 1:200, or 1/4"=1’). Use this when the title block states the scale and sheet, e.g. “1:200 at A1”. bScaler reads the page and works out the true on-screen scale.
By known length (scale bar)
Click Pick two points, click each end of the scale bar (or any line whose real length you know), then type that length. Use this when the drawing has a scale bar but no stated ratio.
Handy tools
⎇Select
Click any measurement or text label to select it. Drag it to move, drag a corner to adjust a shape or resize text, and press Delete to remove it. Selected items are highlighted and shown in the list on the right.
🗇Labels
To keep points easy to see, side and segment lengths are hidden by default (the total or area still shows). Turn Labels on, then click a line or polygon to cycle it: 1) show the side/segment lengths, 2) hide everything, 3) hide nodes, 4) back to the default.
◎Snap
On vector PDFs (most CAD exports) points snap to the ends of, and to points along, the drawing’s own lines - so you can measure corner-to-corner exactly. Turn it on or off in the Ortho & snap panel.
∟Ortho mode
Locks lines to right angles - square to the sheet, or square to two points you pick (for buildings set at an angle).
⚖Units
Switch between metres, millimetres and imperial (feet & inches) at any time, and set how many decimal places (0-3) to show - everything updates live.
TText
Drop your own notes on the drawing. Drag a label to move it, or drag its corner to resize the text.
🔍Box zoom
Click Box, then drag a rectangle around any area to zoom straight to it. Great for reading fine detail.
🎨Colours & list
Every measurement gets its own colour and appears in the panel on the right, with running totals for length and area.
🗑Clear
Click Clear to remove all the measurements on the current page at once and start again.
Quick tips
- Hold Space and drag to pan around a zoomed drawing.
- Hold Ctrl and scroll to zoom in and out.
- While drawing, double-click or press Enter to finish, Esc to cancel.
Please note: measurements are only as accurate as the scale you set and the source drawing. Always verify any critical dimension against a properly scaled source.
bScaler is provided free of charge as an aid for measuring from PDF drawings. No liability is accepted for decisions made using this tool.