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Calcimator

Table Design Calculator

Calculate leg dimensions, apron sizing, taper angles, board footage, and lumber cost for dining and work table projects.

About this calculator

This calculator turns a target tabletop size and height into the leg, apron, and taper dimensions a builder actually cuts to. Apron depth is set to 20% of table height, but clamped between 4" (the structural minimum for rigidity) and 6" (a practical maximum before it looks bulky), so a very short or very tall table won't produce an unreasonable apron. Leg cross-section follows a length-based rule of thumb — tables longer than 60" get a full 3" leg, 42"-60" gets 2.75", and shorter tables get 2.5" — reflecting that a longer, heavier top needs beefier legs to resist racking. For tapered legs, the taper runs from just below the apron (apron depth plus 1/2" clearance) down to the floor, narrowing to 65% of the top dimension; straight and turned-leg styles skip the taper math entirely and keep a constant cross-section.

Apron cut lengths already include 1" tenons on each end, so the number you see is the actual board length to cut, not the shoulder-to-shoulder span between legs. Board footage totals the tabletop, all leg blanks (with a 1/4" milling allowance and 1" trimming margin per leg), and both apron sets, then applies a flat 15% waste factor before pricing at your entered cost per board foot. Seating capacity is a rough guideline assuming 24" of table edge per place setting with a 4" buffer at each end — it's a planning estimate, not a guarantee of comfortable elbow room for every guest.

Inputs

in
in
in
in
in

Results

Leg top cross-section (in)

3

Total board feet (with waste)

37.58

Leg bottom dimension (in)1.95
Leg height (in)29
Taper per side (in)0.53
Apron depth (in)6
Long apron cut length (in)65
Short apron cut length (in)29
Tabletop board feet18
Estimated lumber cost ($)$300.63
Seating capacity6
Taper Length22.5
How to Use This Calculator
  1. Enter Table Length, Width, and Height in inches along with the Top Thickness.
  2. Select Leg Style (straight, tapered, or turned), Number of Legs, and Top Overhang past the apron.
  3. Enter Lumber Cost per board foot to get a material cost estimate.
  4. Review Leg Top Cross-Section, Taper Per Side, Apron Depth, and all cut lengths as your build dimensions.
  5. Check Total Board Feet with waste and Estimated Lumber Cost to plan your material purchase.

What each input means

Table length (in)
Overall tabletop length. Standard 6-person dining table is 72".
Table width (in)
Overall tabletop width. Standard dining is 36-42".
Top thickness (in)
Tabletop thickness. 3/4" to 1" for standard, 1.5"+ for farmhouse style.
Table height (in)
Overall height. Standard dining is 30", counter height is 36".
Top overhang past apron (in)
How far the top extends past the leg/apron assembly.
Leg style (0=Straight 1=Tapered 2=Turned)
Select the leg style (0=straight 1=tapered 2=turned)
Number of legs
Most tables have 4 legs. Trestle tables may use 2 or 3.
Lumber cost ($/BF)
Cost per board foot. Cherry ~$8, Walnut ~$12, Oak ~$6.

What each result means

Leg top cross-section (in)
Square dimension at the top of each leg where aprons join.
Leg bottom dimension (in)
Dimension at the foot. Same as top for straight legs.
Leg height (in)
Leg length from floor to underside of tabletop.
Taper per side (in)
Amount removed from each face during taper (0 for straight legs).
Apron depth (in)
Recommended apron height for structural rigidity.
Long apron cut length (in)
Cut length for the long aprons including tenons.
Short apron cut length (in)
Cut length for the short aprons including tenons.
Tabletop board feet
Board feet of lumber for the tabletop alone.
Total board feet (with waste)
Total lumber including legs, aprons, top, and 15% waste.
Estimated lumber cost ($)
Total lumber cost at the specified price per board foot.
Seating capacity
Estimated seats at 24" per place setting.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Table length (in) = 72, Table width (in) = 36, Top thickness (in) = 1, Table height (in) = 30 = 8 input(s) provided
  2. Calculate Leg top cross-section
    Leg top cross-section = max(minLegSection, apronThickness + 0.5)
    3 = 3
  3. Calculate Total board feet
    Total board feet = netBoardFeet * 1.15
    37.58 = 37.58
  4. Calculate Leg bottom dimension
    Leg bottom dimension = legTopDimension * taperRatio
    1.95 = 1.95
  5. Calculate Leg height
    Leg height = tableHeight - topThickness
    29 = 29

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.

Frequently Asked Questions

Why doesn't a very tall or very short table get a proportionally scaled apron?

Apron depth starts as 20% of table height but is clamped with Math.min/Math.max to stay between 4" and 6", so a 42"-tall counter-height table and a 30"-tall dining table can both land at the same apron depth once 20% of height pushes past that range. The clamp exists because a very deep apron looks bulky and a very shallow one loses structural rigidity, regardless of what pure proportion would suggest.

Why does the recommended leg cross-section jump at 42" and 60" of table length?

The calculator uses a stepped rule of thumb: legs are 2.5" square up to 42" long, 2.75" from 42" to 60", and a full 3" beyond 60", because a longer, heavier top has more racking leverage on the legs and needs a beefier section to resist it. It's a threshold-based lookup, not a continuous formula, so leg size doesn't change gradually as you drag the length slider within a band.

Why are the apron cut lengths shorter than the actual gap between my legs?

longApronLength and shortApronLength already subtract twice the overhang and twice the leg's top cross-section from the tabletop dimensions, then add back 2" total for the 1" tenons on each end — so the number shown is the real board length to cut, tenons included, not the shoulder-to-shoulder distance between leg faces.

Why do straight and turned legs show the same bottom dimension as the top?

The taper ratio is only applied when legStyle equals 1 (tapered); straight and turned legs use a taperRatio of 1.0, which makes legBottomDimension exactly equal to legTopDimension and taperPerSide zero. Only the tapered style narrows the leg toward the floor in this calculator's model.

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