Why does the panel need to 'float' in the groove?

Solid wood panels expand and contract across their width with changes in humidity. The panel is intentionally made slightly narrower than the space between the grooves to leave a gap on either side. This allows the panel to expand without pushing the door frame apart. The panel should not be glued into the groove.

What is a typical stile and rail width?

For standard kitchen cabinet doors, a stile and rail width of 2.25 to 2.5 inches is very common. For larger passage doors or furniture, they can be 4 inches or wider. It's a key element of the door's design and proportion.

How deep should the groove for the panel be?

A typical groove depth is 3/8ths of an inch (0.375"). This provides enough purchase to hold the panel securely. The panel overlap input in the calculator should match the depth of your groove.

Does this calculator work for flat panel or glass panel doors?

Yes, the calculations for the frame (stiles and rails) are exactly the same. The panel dimensions are also the same. The only difference is that instead of a solid raised panel, you would use a piece of 1/4" plywood (for a flat panel) or a glass panel with a retainer molding.

How are the stiles and rails joined together?

The most common method is with specialized 'rail and stile' router bits. These bits cut a decorative profile on the inside edge of the frame and also cut the joinery (a 'cope' on the rails and a 'stick' on the stiles) at the same time. This creates a strong, interlocking joint.

Do I need to change the math for a mortise-and-tenon door?

The overall sizes stay the same; only how the parts connect changes. Stiles still run the full height and rails still fit between them. With loose tenons or drawbored mortise-and-tenon you typically keep the same cut list from this calculator and just swap the router profile for squared tenons, so use the numbers here as your starting layout.

Why do my doors come out a hair undersize after assembly?

Small losses stack up: cope-and-stick cuts remove a sliver of profile, and sanding the raised field pulls the panel thinner. If your finished doors trend a few thousandths small, add a matching allowance to the rail and stile lengths before cutting, then verify with one test door before batching the rest.

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Cabinetry & Furniture

Raised Panel Cabinet Door Calculator

Calculate the dimensions for building a raised panel door.

Building a classic raised panel door requires precise measurements for its five components: two stiles, two rails, and the central panel. The math isn't complex, but it's easy to make a small error that results in a door that's the wrong size or a panel that doesn't fit. This calculator automates these calculations for you.

By providing the desired final dimensions of your door and the width of your frame parts, this tool generates a precise cut list for all components. It also accounts for the depth of the groove that the panel sits in, ensuring the panel is sized perfectly to allow for seasonal wood movement.

Calculator

Enter your measurements and specifications

Overall Door Width

Overall Door Height

Stile Width

Rail Width

Panel Overlap in Groove

Results

Your calculation results and recommendations

Cut List

Stiles (x2): 2.5" W x 0.000" L

Rails (x2): 2.5" W x 0.000" L

Panel (x1): 0.000" W x 0.000" L

Step-by-Step Instructions & Formula

The calculations determine the size of each part based on the overall door dimensions.

Determine Stile Length: The stiles (the vertical frame parts) run the full height of the door. Their length is equal to the final door height.
Calculate Rail Length: The rails (the horizontal frame parts) fit between the stiles. Their length is the overall door width minus the width of two stiles.
Rail Length = Door Width - (2 × Stile Width)
Calculate Panel Dimensions: The panel fits into grooves cut into the inside edges of the stiles and rails. Its size is the 'opening' size plus the depth of the grooves on all four sides.
Panel Width = Rail Length + (2 × Groove Depth) Panel Height = Door Height - (2 × Rail Width) + (2 × Groove Depth)

Real-World Examples

Example 1: An 18″ × 30″ door with 2-1/2″ rails and stiles.
Stiles run the full 30″ height. Rails = 18 − (2 × 2.5) = 13″. With a 3/8″ groove overlap the panel becomes 13 + 0.75 = 13.75″ wide and 30 − 5 + 0.75 = 25.75″ tall. That's your whole five-piece cut list.

Example 2: A wider 21″ door, same frame.
Rails grow to 21 − 5 = 16″ and the panel to 16.75″ across. Notice only the rails and panel width change with door width; the stile length and panel height stay tied to the height. Set the height once and vary width across a bank of doors.

Example 3: Sizing for movement.
The calculator gives the panel that reaches fully into both grooves. For a solid panel, knock about 1/8″ off the width (the cross-grain dimension) so it can swell into that gap instead of jacking the stiles apart in summer.

Common Mistakes & Troubleshooting

Gluing the panel into the groove. A trapped solid panel expands across its width and splits the frame or pops the joints. Float it; glue only the frame miter/cope corners.
Sizing the panel to the full opening. Making the panel exactly railLength ignores the groove depth, so it won't reach both grooves. Add the two overlap depths, as the tool does.
Forgetting rails fit between stiles. Cutting rails the full door width makes the frame too wide. Rails are door width minus two stiles.
Mismatching overlap to your bit. Enter the groove depth your rail-and-stile bit actually cuts. A 1/4″ groove fed as 3/8″ gives a panel too big to seat.

Expert Insights

"I cut one full door as a trial before committing a whole kitchen. Assemble it dry, feel how the panel sits in the grooves, and check the diagonals. If the test door is square and the panel floats freely, the numbers carry to every door in the set." — Cabinet Shop Lead

"Panel width is the number that bites, because it's the cross-grain dimension that moves. I'd rather leave a touch more float than a touch less. A small visible gap in the groove disappears when the humidity rises; a tight panel never does."

Glossary of Terms

Stile: The vertical members of the door frame.
Rail: The horizontal members of the door frame.
Raised Panel: The central panel of the door, which has a profile cut around its edges so that it is thinner where it fits into the frame's groove.
Groove: The slot cut into the inside edge of the stiles and rails to accept the panel.
Wood Movement: The natural expansion and contraction of wood due to changes in humidity. Panels must be sized to 'float' in the groove to allow for this.

Frequently Asked Questions

Written by

WoodCalc Editorial Team

DIY woodworkers & shop practitioners

Reviewed by

Jordan Vale

Journeyman carpenter & shop-math reviewer

Updated Jan 10, 2026

How we calculate & sources

Formulas follow accepted woodworking practice and cited building-code / industry standards. Results are estimates — always verify against your own material and local code.

Wood Handbook — Wood as an Engineering Material (USDA Forest Service)
International Residential Code (IRC), Span Tables

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Pro Tips

Always double-check your measurements before cutting.
Account for the kerf (the width of the saw blade) in your calculations.
Consider wood movement (expansion and contraction) in your final dimensions.
Buy 10-15% extra material to account for mistakes and waste.