Mortise and Tenon Calculator – Free Joint Sizing Tool

🔨 Mortise and Tenon Calculator

Size traditional furniture joints with practical rules for thickness, length, shoulders, glue area, and fit clearance.

Unit System
Calculator Inputs
Thickness of the rail or stretcher carrying the tenon.
Available width for shoulders and tenon cheeks.
Thickness of the leg, stile, or post receiving the mortise.
Face width that sets the mortise opening and edge margins.
Practical Tips
Tip 1: Keep the tenon thickness near one-third of the stock thickness. If the rail is wide, a double tenon is usually safer than making one extra-thin cheek.
Tip 2: Dry-fit before glue-up. A mortise and tenon joint should feel snug and controlled, not forced by clamps or a hammer.
Quick Presets
Real workshop setups
📊 Joint Sizing Results
Recommended Tenon Size
-
thickness x width x length
Mortise Opening
-
opening x depth and edge margin
Cheek Glue Area
-
bonding area on both cheeks
Joint Strength Index
-
fit, species, and duty balance

Calculation Breakdown

Material and Spec Grid
0.35 g/cc
Soft Pine
Low density, softer cheeks, best for light frames and paint-grade joinery.
0.75 g/cc
White Oak
Strong, stable, and ideal for chairs, doors, and traditional furniture frames.
0.70 g/cc
Hard Maple
Dense and durable with crisp shoulders, a good choice for precision joints.
0.55 g/cc
Black Walnut
Moderate density with good working qualities for casework and cabinet frames.
Tenon Thickness Reference
Stock Thickness Standard Tenon Heavy Duty Typical Use
3/4 in1/4 in5/16 inChair rails, light frames
7/8 in5/16 in3/8 inTable aprons, stiles
1 in5/16 to 3/8 in3/8 inDoors and cabinet frames
1 1/4 in3/8 in7/16 inHeavier rails and legs
1 1/2 in7/16 in1/2 inBenches, gates, outdoor work
Length and Depth Rules
Joint Style Length Factor Mortise Depth Rule Best Use
Standard Blind4x tenon thicknessAbout 80% of depthGeneral furniture
Through Tenon4.2x thicknessFull depth plus proud endVisible joinery
Haunched Tenon3.8x thickness80% to 90% of depthFrames with narrow top rails
Wedged Through4.4x thicknessFull depth plus wedge roomExterior and structural work
Double / Twin4x thicknessSame as singleWide rails and heavy members
Fit Clearance by Method
Cutting Method Typical Clearance Fit Class Notes
Hand Saw + Chisel0.010 to 0.015 inHand CutLeave room for tuning the cheeks
Hollow Chisel Mortiser0.005 to 0.010 inStandardGood for repeatable furniture parts
Router + Jig0.003 to 0.008 inSnugExcellent for loose tenons and batches
CNC0.002 to 0.004 inCNC / MachineUse a test cut before production
Wide Mortise0.008 to 0.012 inLooseGood when seasonal movement matters
Common Joinery Applications
Application Typical Stock Recommended Style Practical Note
Dining Chair Rail3/4 x 2-1/2 inBlind or haunchedKeep shoulders crisp and consistent
Table Apron7/8 x 3 inStandard blindSize cheeks for glue, not just hold
Door Stile1-1/4 x 3 inThrough or wedgedProtruding ends can be a design feature
Workbench Stretcher1-1/2 x 4 inDouble tenonUse more cheek area for heavier loads
Outdoor Gate1-3/4 x 4 inWedged throughAllow for movement and seasonal swelling
Workshop Notes
Tip 3: If the mortised member is wide, place the mortise so the remaining edge margins stay even. That keeps the joint looking balanced and helps resist splitting.
Tip 4: For wide rails, two smaller tenons often outperform one oversized tenon because the shoulders carry the alignment and the cheeks carry the glue.
Safety note: Use guards, sharp chisels, and stable workholding. Keep hands clear of cutters, and never force a fit that could split the mortise walls or kick the workpiece loose.

Mortizo and tenona joint forms basic link between two dissimilar wooden bits. It allows to tie two parts from wood or alike material. In one bit, called the pole, one tailas hole or split, that one calls mortizon.

It usually has square or rectangle form, although round or others shape are possible according to the plan. The tenono is grinded bit at the finish of the kuniga wood, that answers in the mortizo. Ideal tenono slip in its mortizon by means of simple handshake.

How to make a mortise and tenon joint

With glue in the space it does firm link.

This link used lignistoj during thousands of years. One considers it the most ancient and the most rugged kind in lignarbaro. It answers well for tie two lignpecojn in 90-grada corner.

One encloses the tenonon in the mortizon what creates mechanical strong link against traction and tordado. That gives tridimensian stability without need of seals as nails or screws. Humanitarian link kunveniĝas by means of hand and stay flatly even if one raises the tenonan part.

For do the link cut first the mortizon and later adaptiĝigu the tenonon. Do the tenonon a bit shorter than the mortizoprofondo around 1/16 inches. That little space accepts trogluon and ban that the tenono elprotrudiĝu what could brake the surface.

If it too thick tailu it a bit and remove slim slices of the aspects by means of knife for reach the apt extent. Tailu before the cheeks than the shoulders. Like this one escapes to cut preter the line and weaken the tenonon.

Many utilities answer for the task. Use drill with cizelo either mortizmaŝinon. Some favours frezilmaŝinon or drill with mortiza appendix.

For the tenono hold-seĝilo tablovido either jig-seĝilo operate well. Ŝultra knife helps to refine the extent. Precise measures are inherent for reach accuracey.

Mortise and Tenon Calculator – Free Joint Sizing Tool

Author

  • Thomas Martinez

    Hi, I am Thomas Martinez, the owner of ToolCroze.com! As a passionate DIY enthusiast and a firm believer in the power of quality tools, I created this platform to share my knowledge and experiences with fellow craftsmen and handywomen alike.

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