Calculate Scale

Scale a photo of a real object to an exact size. Draw a line over something you've measured (a door, a wall, a vehicle), type its real length, and Calculate Scale works out the scale and resizes the photo to the scale you want to design at.

In the PowerScript packages · Version 1.1.6 · Needs PowerScripts 3.8.32 or later

Open the PowerScripts panel (Window > Extensions > PowerScripts) and choose Calculate Scale from the Tools scripts.

1. Place the photo in Illustrator.
2. Draw a straight line over something you measured, for example the width of a door.
3. Select the line and press Calc Scale. Type the real size with its units, for example 915mm or 36 in.
4. Enter the Desired Scale you want to design at, for example 10 for 10%.
5. Select the photo and press Apply Scale.

• Separate scale for horizontal and vertical: work out the scale across and down separately, with Calc Horizontal Scale and Calc Vertical Scale. Use it when the photo is stretched or taken at an angle.
• Calculated Scale: the scale the photo is at now, worked out from your line. You can also type it if you know it.
• Calc Scale: select one straight line, press it, and type the line's real length with units. The scale is the line's length on the page divided by its real length.
• Desired Scale: the scale you want the artwork at, for example 100% for full size or 10% for a large sign.
• Add Scale Label: write “SCALE: 10.00%” at the bottom left of the scaled artwork.
• Apply Scale: scales the selected artwork from the calculated scale to the desired one.

1. Place the photo of the shop front.
2. Draw a line across the door, which you measured as 915 mm.
   
3. Select the line, press Calc Scale and type 915mm.
   
4. Set Desired Scale to 10.
5. Select the photo and press Apply Scale. The photo is now at 10%, so 1 mm on the artboard is 10 mm on the building.
   
6. Design the sign at 10% on top of the photo. Use Dimension with the same scale to add real-world measurements.

• Measure the longest thing you can in the photo: a longer line gives a more accurate scale.
• Draw the line on something flat-on to the camera. Things at an angle look shorter than they are.

• Calc Scale needs one straight line selected (two points). Anything else and the panel asks you to select a single line.
• Always type the units: 915 on its own isn't enough, 915mm is.

• 1.1.6: Buy in PowerScripts now opens the packages that include this script.
• 1.1.5: Updated for PowerScripts 3.8.32.
• 1.1.4: Updated for the new version of PowerScripts.
• Older changes: PowerScripts Release Notes