Interactive Room & Floor Plan Builder
Check measurement changes before buying cartons ↓
Draw the space you actually have—not just a rectangle. Set exact wall lengths, combine rooms and floors, trace a plan image, and turn the finished drawing into material quantities.
Your drawing becomes the estimate
Planning assumptions
Material plan
Save, share, or move the plan
Named saves stay in this browser. Shared links include geometry and measurements, but never include the tracing image.
What this tool calculates
Closed room outlines use coordinate geometry to calculate floor area and wall perimeter. Exclusions are subtracted from floor coverage. Door and window dimensions are subtracted from paint and drywall wall area; door widths are also removed from baseboard length.
Accuracy and limitations
This is a planning tool, not architectural or structural design software. It does not verify load paths, wall construction, egress, code compliance, shared-wall duplication, or whether separate rooms overlap. Confirm critical dimensions and product coverage before purchasing or building.
Start with a field sketch
Walk the perimeter in one direction and record each wall length in sequence. Note which corners are square, where the outline steps in or out, and which dimensions are checks rather than perimeter edges. A diagonal measurement can help confirm a rectangular section before you build the digital plan.
Create separate rooms or floors when spaces do not share one continuous outline. Use exclusions for voids that truly do not receive material, and use doors and windows only for wall-finish calculations.
Audit the plan before estimating materials
Compare the displayed perimeter and area with a simple hand check. Zoom in for small offsets, confirm units, and review every labeled edge. Save or export the measurements you relied on; the drawing is planning documentation, not a survey or construction drawing.
Check the room before trusting the carton count
For the hypothetical 10 × 10 ft room with a 4 × 6 ft missing corner, area is 76 sq ft. If each of those four dimensions could differ by one inch, conservative smaller- and larger-area scenarios are 73.5 and 78.5 sq ft. At 20 sq ft per box and 10% extra, all three still need 5 boxes. Try a different carton coverage to see when that decision changes.
Bounds are deliberately conservative what-if cases, not a survey tolerance or confidence interval. The smaller case decreases both outer dimensions and increases both recess dimensions; the larger case does the reverse. The model assumes perpendicular edges and one rectangular missing corner. It does not validate the actual shape or plan a cutting layout.
Four checks to make before ordering
- Sketch and label each edge. For this L-shape, horizontal return lengths must sum to the outer length, and vertical return lengths to the outer width. A mismatch means remeasure; it is not a reason to stretch the drawing.
- Do not assume a room is square. For an intended rectangle, compare both diagonals and the side measurements. A difference is a reason to check the outline, not proof of a particular construction defect.
- Keep room dimensions and excluded areas in consistent units. A floor opening removes floor area; a window usually changes wall paint, not floor-level trim.
- Check usable carton coverage, installation direction, product suitability and return terms. Whole-box coverage above measured area includes allowance and rounding; it is not all avoidable waste.
Draw a non-rectangular outline · Build the room shopping worksheet · Inspect the calculation checks