If you’re learning AutoCAD or need a clear, step-by-step reference, this guide explains how to use the AREA command (and alternatives) to calculate area and perimeter accurately. You’ll find practical steps, common problems and fixes, alternative methods, and helpful tips for reliable results.
What the AREA command does
The AREA command in AutoCAD calculates the area and perimeter of:
- a closed object (circle, closed polyline, rectangle, etc.),
- a region defined by specified points,
- a combination of objects using Add/Subtract options.
When you run the command, AutoCAD reports the area (in square drawing units) and the perimeter (linear units) in the command line.
When to use AREA vs alternatives
Use AREA when you need a quick measure of a single closed object or a polygon defined by points. Use alternatives in these situations:
- the object is not closed (use BOUNDARY, PEDIT/JOIN, or REGION first);
- you need area for hatched regions (inspect the Hatch properties);
- you need volume or surface area of 3D solids (use MASSPROP);
- you prefer a different workflow (use MEASUREGEOM, LIST, or PROPERTIES).
How to use the AREA command — step by step
- Type AREA and press Enter.
- Choose one of the options by typing the letter shown:
- Object (type O) — select a single closed object.
- Add — add areas from additional objects or points.
- Subtract — subtract areas (for holes).
- (Or simply specify points to define a polygon).
- If you choose Object:
- Type O, then pick the closed object (polyline, circle, etc.), then press Enter.
- AutoCAD displays Area = and Perimeter = in the command line.
- If you specify points:
- Click points sequentially to create the polygon boundary, then press Enter. The command prints area and perimeter.
- To combine or exclude areas:
- After the first area measurement, use Add to pick more objects or specify points; use Subtract to remove internal holes. When done, press Enter to finish.
- To measure multiple separate closed objects at once:
- Start AREA, type O (Object), and select multiple closed objects before pressing Enter; AutoCAD reports the total area and combined perimeter.
Keyboard shortcut summary:
- AREA → O → select object → Enter
- AREA → pick points → Enter
- Or use MEASUREGEOM → A → follow prompts for point selection or objects (see alternatives).
Examples (common workflows)
-
Measure a rectangle:
- Click the rectangle (a closed polyline). Command line shows area in square drawing units and perimeter.
-
Measure a circle:
- Use AREA → O → select the circle. Area = πr², shown automatically.
-
Measure an L-shaped region with a hole:
- Use AREA → Object to measure the outer closed polyline (or specify points), then use Subtract to pick the inner closed polyline (the hole). The result is outer minus inner area.
-
Irregular polygon where you don’t have a closed object:
- Type AREA and click the vertices in order; close the polygon with Enter. If segments are slightly open, use PEDIT or JOIN or run BOUNDARY to create a closed polyline first.
Alternative methods to get area or perimeter
- MEASUREGEOM (command): type MEASUREGEOM → A. Works similarly for area calculations with a slightly different prompt layout.
- PROPERTIES palette: select a closed polyline or hatch; the Properties window shows Area and Perimeter/Length.
- LIST command: type LIST, select the object — the text output includes area for closed entities.
- HATCH object: after creating a hatch, select it and view the area in the Properties panel.
- REGION + MASSPROP: convert multiple closed objects to a REGION to combine them, then run MASSPROP for accurate area and mass properties (also useful for volumes on 3D solids).
- BOUNDARY: create a closed polyline from crossing geometry, then measure that polyline.
- QuickCalc or calculator: use to convert units (e.g., sq ft to sq m) after obtaining area.
Common errors and how to fix them
-
Problem: AREA returns 0 or an incorrect value.
- Cause: The object is not closed (tiny gaps or endpoints don’t meet).
- Fix: Use ZOOM in to inspect, then PEDIT → JOIN, EXTEND, FILLET (radius 0), or run BOUNDARY to create a closed polyline. You can also use REGION on overlapping closed curves.
-
Problem: Area measured is wrong because shapes are 3D or tilted.
- Cause: Objects are in different Z elevations or not on the same plane.
- Fix: Set the UCS to the object plane or flatten the geometry (use FLATTEN or align objects to 0 Z) before measuring. For 3D solids, use MASSPROP.
-
Problem: Units confusion — area seems too large or small.
- Cause: Drawing units (UNITS) vs desired measurement units.
- Fix: Check UNITS to confirm drawing units. Convert the area by applying the appropriate square-unit conversion factor (use QuickCalc).
-
Problem: AREA can’t measure block contents or referenced geometry.
- Cause: Block reference or Xref geometry might not be directly measured as separate closed objects.
- Fix: Explode the block (if appropriate) or open the block and measure there; for Xrefs, bind or open the xref to measure inside it, or use BEDIT to edit block definitions.
-
Problem: Need perimeter but command only shows area.
- Solution: AREA reports both Area and Perimeter in the command line when measuring closed objects. Alternatively, use the Properties palette which lists Area and Perimeter/Length.
Practical tips for accurate area measurement
- Always confirm the drawing units (UNITS command) before trusting area numbers — area output is in square drawing units.
- Increase numeric precision in Units or Properties if you need more decimals.
- Use JOIN or PEDIT to convert multiple segments into a single closed polyline for reliable area calculation.
- For complex shapes with holes, use the Add/Subtract options in AREA, or create a single REGION and run MASSPROP.
- For repeated tasks, create a small workflow: create boundary → convert to polyline → check properties → record area.
- If you need to include/exclude small gaps automatically, use BOUNDARY with a small tolerance to generate closed polylines from overlapping objects.
- For unit conversions, multiply the reported area by the square of the linear conversion factor (e.g., to convert sq inches to sq feet, multiply by (1/12)^2 = 1/144).
FAQ
How do I measure the area of an irregular shape that isn’t a closed object?
Use AREA and click vertices to define the polygon, or create a closed boundary using BOUNDARY or join the segments with PEDIT to form a closed polyline, then use AREA or check the Properties.
Why does AREA report an unexpected value when measuring a block or xref?
Block references and xrefs can behave differently. Either explode the block (if safe), measure within the block editor, or bind the xref. Also ensure no scaling or UCS transformations affect the block.
How do I measure the area of a shape with holes (donuts)?
Use AREA with Add and Subtract options: measure the outer region, then Subtract the inner hole(s). Alternatively create separate regions and use REGION + MASSPROP.
How can I get area in different units (for example, from square mm to square m)?
Check your drawing units (UNITS). After getting the area in drawing units, convert using the square of the linear conversion factor (e.g., to convert mm² to m² divide by 1,000,000). Use QuickCalc to do the calculation quickly.
AREA shows a number but I need the perimeter too — where is it?
When AREA completes, AutoCAD prints both Area = and Perimeter = in the command line. You can also see perimeter (length) in the Properties window for closed polylines.
How do I calculate area for a 3D solid or get surface area vs volume?
Use MASSPROP for 3D solids: it reports volume and surface area (mass properties). For planar faces, convert the face to a region or extract the boundary, then use AREA.
AREA doesn’t work even though my polyline looks closed — what should I check?
Zoom in to verify endpoints exactly meet; check for tiny gaps, duplicate overlapping segments, or very small arcs. Use OVERKILL to clean duplicates, JOIN to combine segments, or redraw small segments. Running BOUNDARY often helps capture the intended closed region.
Can I measure multiple, separate closed objects at once?
Yes. Use AREA → Object and select multiple closed objects before pressing Enter. AutoCAD returns the total combined area and the sum of perimeters.