To measure length in SketchUp, select the edges or the arc with the Select tool and read the total in Entity Info; use the Tape Measure only for a single stretch between two points. Curves and trim need a little more care: a run of straight segments reads slightly short of the curve it approximates, and a baseboard modeled as loose lines has no length you can list, while one modeled as a component does.
Reading a length: Entity Info and Tape Measure
Three ways cover most jobs.
- One line or stretch: Tape Measure. Press Ctrl to cycle the tool to Measure mode, click the start and end points, and the distance appears in the Measurements box. Hovering over a line with the tool active also shows its measurement (SketchUp help).
- Several edges: Entity Info. Select the edges and open Entity Info. Forum moderators give the same answer to every version of the question: it tells you the number of segments and the total length (SketchUp forum).
- A drawn perimeter: edges only. To total the walls around a room, select the perimeter edges; if the face is in the selection, Entity Info shows nothing (SketchUp forum).
When Entity Info stays blank on a bigger selection, a guide, dimension, text, group or component is usually in it. A forum answer suggests Wireframe face style, which leaves faces out of the pick, and putting text and dimensions on a tag you can switch off (SketchUp forum). The same answer works for a floor plan of pipes or cable drawn as edges and arcs (SketchUp forum).
How to measure curve length in SketchUp, and the trap in the total
An arc is one entity built from straight segments, 12 by default, and you can change the count (SketchUp help). That is the source of the trap. A forum answer explains that for a SketchUp arc or circle the true curve length is reported, but for a polyline drawn by hand the total is the sum of straight segments, which is a little less than the curve, so buy slightly more than listed (SketchUp forum). The poster in that thread asked how much more; the answer, from a test file, was a few inches per hundred feet for a highly segmented line.
The size of the gap follows from geometry. The table is an illustration, computed by hand for a quarter circle of 1,000 mm radius, whose true arc length is π/2 × 1,000 = 1,570.8 mm; the chords of n equal segments add up to n × 2 × 1,000 × sin(π/4n).
| Segments | Sum of chords (mm) | Shortfall (mm) | Shortfall (%) |
|---|---|---|---|
| 6 | 1,566.3 | 4.5 | 0.29 |
| 12 | 1,569.7 | 1.1 | 0.07 |
| 24 | 1,570.5 | 0.3 | 0.02 |
Doubling the segment count cuts the shortfall to about a quarter. For a stair stringer or a curved edging strip, either select the arc itself and read its length, or add roughly a percent when the length comes from a rough polyline, and write down which of the two you did.
Lineal feet of baseboard in SketchUp: model the trim as components
Skirting and baseboard are bought by the run, then cut to wall lengths. Forum users ask for exactly this, such as the linear footage of cove base and wall trim without clicking every piece (SketchUp forum). The reply there was to draw around the room, select the edges and read Entity Info, which works for the net run. It does not give a list of pieces, and it breaks as soon as the trim is a solid. Another contributor makes the general point: parts you need to count should be components or groups, not loose lines (SketchUp forum).
- Extrude the profile. Follow Me leads a face along a path and suits crown molding and similar trim (SketchUp help). Make each straight wall run its own piece.
- Make each piece a component. One instance then equals one cut piece, and a repeated piece is one definition with a count.
- Put the trim on its own tag so it can be selected, hidden and listed apart from walls and doors.
- Read the lengths from the component sizes, or total them with a table (next sections).
Illustration with invented dimensions: a 4.20 m × 3.60 m room with one 0.90 m door opening.
| Baseboard piece | Length (m) |
|---|---|
| North wall | 4.20 |
| South wall | 4.20 |
| East wall | 3.60 |
| West wall (door gap removed) | 2.70 |
| Net run | 14.70 |
The perimeter is 2 × (4.20 + 3.60) = 15.60 m, less the 0.90 m opening, so 14.70 m net. Add 10% for cuts and mistakes: 14.70 × 1.10 = 16.17 m, which is 6.74 lengths of 2.40 m stock, so 7. Cutting each wall from its own stock lengths without reusing offcuts needs 2 + 2 + 2 + 2 = 8 lengths (4.20 and 3.60 and 2.70 each need two 2.40 m lengths). The total and the order are different numbers; the second depends on how you cut and join. Mitred corners, scarf joints and the real stock length are yours to confirm.
Where a spreadsheet takeoff helps
Entity Info gives one total for one selection and forgets it when you click away. Generate Report lists components but its LenX, LenY and LenZ are bounding-box sizes, not edge lengths (SketchUp forum; SketchUp help). For a table that stays with the model, SheetUp (SketchUp 2022 and newer) keeps rows in the .skp and re-measures about a second and a half after the model changes. Add an Object row for each trim component, or a Tag row for the whole trim tag, and use the Length input.
What that Length is matters here. For an Object row it is the longest side of the component’s own bounding box, scaled, so it does not change when the piece is rotated, multiplied by the instance count when you use it as an input. A straight baseboard piece reads its length, and six identical pieces read six times that. It is not an edge sum, a perimeter or a curve length, and SheetUp has no measure for raw edges, curves or loose selections. A mitred or L-shaped piece reads the long side of its box, which can differ from the centre-line length of the trim. That limit is the reason to model trim as straight components first. Waste is a percentage that scales the cost, not the length figure, so the length column stays the net run. Rows export to one Excel sheet with live formulas for line costs and totals, CSV or an HTML report, and the free allowance counts saved export files per day; adding, viewing, editing and pricing rows is unlimited. For pricing the rows, see SketchUp cost estimate, and for the other extension options SketchUp quantity takeoff extensions.
What I could not check
- I did not run SketchUp for this article. The Entity Info behaviour (edge totals, the arc-versus-polyline difference, the blank total when a face or group is selected) comes from forum answers dated 2014 to 2026, not from the help pages: the Entity Info help page does not describe length.
- Whether the current release still reports an arc at its true length and a hand-drawn polyline as a segment sum; the forum answer is from 2014.
- What the Text tool’s length label gives on welded edges; one moderator mentions it, I did not test it.
- How SheetUp’s Tag row Length input behaves on a tag that holds a mix of straight and mitred pieces beyond the per-instance total.
- Stock lengths, mitre allowances and offcut reuse in the trim illustration; the figures are invented.
Sources
- SketchUp help: Measuring Distance; Drawing Arcs; Extruding with Follow Me; Using SketchUp’s Generate Report Service (opened 2026-11-10)
- Forum: How do we calculate lineal feet for curving lines with many segments? (2014); Calculating all line lengths (2018); Total length of all items in an group (edges+arcs) (2020); Takeoff Measuring Tool Extensions (2022); Open up Generate Report to API (2021); Tally of exterior walls (2026)
- SheetUp behaviour: read from the extension’s documentation and source, 2026-11-10.
FAQ
How do I measure arc length in SketchUp?
Select the arc with the Select tool and read the length in Entity Info. A forum answer notes that for a SketchUp arc or circle the true curve length is reported, while a hand-drawn polyline of straight segments reports the sum of its segments (SketchUp forum). The Tape Measure reads a single stretch of line, so it is the wrong tool for a whole curve.
Why is the total of my selected curve shorter than the real curve?
Each segment is straight, so the segments together are a little shorter than the curve they approximate. In the thread on lineal feet for curving lines the advice was to order slightly more than listed (SketchUp forum). The table above shows the size of the gap for a quarter circle.
Why does Entity Info show no length for my selection?
Two causes appear in forum answers: a face is in the selection (SketchUp forum), or a guide, dimension, text, group or component is (SketchUp forum). Switch the face style to Wireframe, select only edges and arcs, and the total returns.
Can Generate Report give the length of edges or curves?
No. Its LenX, LenY and LenZ attributes are the bounding-box dimensions of a component, and a forum user described it as unable to deal with edge lengths (SketchUp forum; SketchUp help). Model each run as a component if you want it in that table.
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