Scale defines the relationship between distances on your plan and actual distances in the real world. Without correct scale, all measurements and area calculations will be wrong. Each page in a project maintains its own scale setting.

Exayard attempts to detect scale automatically during upload by reading scale notations, title blocks, and scale bars on the drawing. When detection succeeds, the scale appears in the toolbar above the plan, next to the page name, search box, and page menu. A blue hint reading "AI-detected scale may need calibration for scanned documents" can appear with a Draw a known distance link that starts the same flow described below.

Click the scale button in the toolbar above the plan (it shows Set scale if no scale is set, or the current scale value). The button appears once you select a plan page. On a PDF sheet, a popover opens with Imperial and Metric tabs. On an image sheet, it opens with a warning first, as described below. Browse common presets organized by type:

Click a preset to apply it. To remove the scale, click Clear scale at the bottom of the popover.

For non-standard scales, use the custom entry fields under the presets. On the Imperial tab, enter drawing inches and real-world feet (for example, 1 inches = 25 feet). On the Metric tab, enter the ratio as two numbers (for example, 1:150). The scale saves automatically as you type.

The most accurate calibration method uses a known dimension from your plan. Click the scale button, then click Draw a known distance. On a PDF sheet it sits under the custom entry fields at the bottom of the popover. When the popover opens with a note at the top, such as the blue hint about an AI-detected scale, it is a link in that note instead. On an image sheet it is at the top, in the warning.

A blue prompt appears reading "Click and drag to draw a reference line." Press at the start of a marked dimension, drag to its end, and release.

A dialog titled Set scale from distance appears showing the current line length. Enter the actual distance under Actual distance using feet, inches, and fractions. Click Set scale to apply the calibration.

For best results, use the longest clearly-marked dimension available. Zoom in closely before drawing to minimize placement error. The reference line stays on the page after calibration. To remove it, reopen the scale popover and click Clear reference line in the Scale set from a known distance panel.

A sheet uploaded as an image file (JPEG, PNG, or another image format) carries no page size. A printed ratio such as 1/4" = 1' can only be guessed on it, so the scale popover leads with a known distance instead. It opens with a warning: "This sheet is an image, so a printed scale may be wrong. Draw a known distance to set it." Click Draw a known distance in that warning to calibrate from a dimension on the plan.

The Imperial and Metric tabs, their presets, and the custom entry fields stay hidden at first. Click Use a printed ratio anyway to show them. If you already chose a printed ratio on that sheet, they stay open.

If Exayard worked out a scale for an image sheet during upload, the scale button shows Not calibrated. The warning then reads Scale not calibrated, with the same Draw a known distance button.

When you capture aerial imagery through the Aerial survey feature, scale is calculated automatically based on the map's zoom level and geographic location. No manual calibration is needed. See Uploading PDFs and images for supported file types and upload details.

After setting scale, measure a known dimension that you did not use for calibration. If your measurement closely matches the printed value, the scale is accurate. If it differs significantly, recalibrate using a different reference dimension.

Different pages often have different scales. Site plans commonly use engineering scales (1" = 20') while floor plans use architectural scales (1/4" = 1'). Always verify scale on each page before measuring.

If measurements seem too large or small, the scale is likely incorrect. Recalibrate using a known dimension. For plans scanned at non-standard resolutions, trust your calibration against known dimensions rather than graphic scale bars. Always calibrate before measuring to avoid redoing work.