Inside corner: back edge is long
At a 90° inside corner, the back edge that touches the wall reaches the corner. The finished front edge becomes shorter after the 45° cut.
Free visual trim planner
Plan every baseboard and quarter-round miter cut
Draw the room, choose baseboard or quarter round, and enter each wall length. The planner makes a printable cut card for every piece with the inside or outside 45° miter, long edge, keep side, and upright miter-saw position.
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1Build the roomDrag wall pieces.
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2Add wall lengthsMeasure the wall edge.
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3Stand it on the miter sawWall side to fence. Bottom to table.
Square rooms and 90° corners
Build your cut plan
Drag a wall piece onto the grid to start your room.
Step 1 of 3
Build the room
Drag in wall pieces. Move a whole piece from its middle, or grab either round end to resize and rotate it.
Step 2 of 3
Add each wall length
Measure corner to corner along the wall where the back of the trim will touch.
Current wall Measured
Wall 1 of 4WALL A
Step 3 of 3
Cut one board at a time
Stand inside the room and face the highlighted wall. LEFT and RIGHT are from that view.
Your plan
0 boards
BACK / WALLFRONT / ROOM✓ KEEP✕ WASTE
Board-by-board directions
How to read baseboard and quarter-round cut cards
Every cut card matches one labeled wall in your room drawing. Use the wall measurement on the back or wall-flat edge—the edge against the wall. The card shows which end to cut, whether the saw turns left or right, which side to keep, and how to stand the baseboard or quarter round upright.
| End type | Saw setting | Long edge |
|---|---|---|
| Inside corner | 45° | Back / wall edge |
| Outside corner | 45° | Front / room edge |
| Door or no-trim opening | 0° | Square end |
Outside corner: front edge is long
At a 90° outside corner, the finished front edge wraps around the corner and becomes the long point. The back edge stops at the wall corner.
Door or opening: use a square end
When trim stops at a doorway, casing, or other opening, the planner calls for a 0° square cut instead of a corner miter.
Measure the wall edge
How to measure baseboard and quarter round for 45° miter cuts
Measure each wall corner to corner at trim height. Enter that measurement in feet, inches, and fractions. The planner puts it on the back or wall-flat edge—the edge against the wall—so the cut card can show the correct long point and waste side. The room drawing shows the shape; your measurement controls the cut length.
Quarter-round miter guide
How to cut quarter round for inside and outside corners
Choose Quarter round in step one. The planner changes every printable card to show the wall-flat side, floor-flat side, rounded face, saw direction, long point, waste, and piece to keep. It creates miter-cut cards for 90° corners; it does not calculate coped joints or off-angle corners.
1. Stand it like it installs
Keep the wall-flat side against the saw fence, the floor-flat side on the saw table, and the rounded face toward you.
2. Use 45° for a 90° corner
Turn the miter saw left or right to 45° for inside and outside corners. Use a 0° square cut where the quarter round stops at a doorway or no-trim opening.
3. Dry-fit before nailing
Follow the cut card's long point and keep side. Leave the piece slightly long when unsure, then test the joint before shortening it.
Real rooms are not perfectly square
This planner makes a clear starting plan for 90° corners. Measure twice at trim height. Use scrap to test the angle, leave the trim slightly long when unsure, and shorten it only after a dry fit. Inside corners can also be coped; coping is not included in this planner.
Common questions
Baseboard and quarter-round cut planner FAQ
What angle do I cut baseboard for a 90° corner?
Cut each mating board at 45° so the two pieces form a 90° corner.
Do I cut the front or back of baseboard?
A 45° cut passes through the whole board. At an inside corner, the back edge that touches the wall is the long point. At an outside corner, the finished front edge is the long point.
Where do I measure a wall for this planner?
Measure corner to corner along the wall at trim height. Every cut card puts that measurement on the back edge of the board—the edge that touches the wall.
How do I tell an inside corner from an outside corner?
An inside corner folds inward, like a corner in a simple bedroom. An outside corner projects into the room, like the edge of a column or a short return wall.
Does this work for corners that are not 90°?
No. This planner currently creates 45° miter cut cards for 90° room corners. Make a scrap test and dry-fit every piece because real walls can vary.
Should I cope inside baseboard corners?
Coping often fits imperfect inside corners better. This planner currently creates miter cut cards for 90° corners; it does not create coping instructions.
Can I print the baseboard cut cards?
Yes. After entering every wall measurement, choose Print all cut cards to make a board-by-board reference for the saw.
How do I cut quarter round with this planner?
Choose Quarter round in step one. Keep its wall-flat side against the miter-saw fence, floor-flat side on the table, and rounded face toward you. Each cut card shows the saw direction, long point, waste, and keep side.
What angle do I cut quarter round for a 90° corner?
Set the miter saw to 45° for each mating piece so they form a 90° inside or outside corner. Use a 0° square cut where the quarter round stops at a doorway or no-trim opening.
Is my room plan uploaded?
No. The room shape and measurements stay in your browser and are not uploaded. Nothing is saved unless you turn on Save on this device.