Blade Height Calculator

Blade Height Calculator for table saws. Enter stock thickness and cut type to get the tallest-tooth height for a rip, dado, box joint or half-lap, plus handwheel turns to reach it.

Setting Table Saw Depth With the Blade Height Calculator

The Blade Height Calculator sets a table saw blade for through cuts and for joinery. Rips and crosscuts are covered, along with dados, grooves, box joint slots and half-laps. It returns the height from the table to the tip of the tallest tooth, then checks that height against blade maker and saw maker guidance.

It is built for woodworkers who set height by eye and want a number, and for anyone cutting joinery where depth decides the fit. Presets load the SawStop PCS or CNS and two DeWalt jobsite saws, and any other saw works with its own specs typed in.

How Each Cut Type Sets the Height

Measure the stock with calipers rather than trusting its label. Every thickness here is the actual, finished size, not a nominal size, and the math runs in inches with a millimeter option. A through cut, rip or crosscut, is the stock thickness plus the amount you want showing above it.

$$h=t+e$$

A dado or groove takes a share of the board thickness instead. The common rule, a convention and not a standard, is one-third of the board and never more than half. Replies in a Fine Woodworking dado depth thread give that rule, and a Sawmill Creek thread gives the same half-thickness ceiling.

$$h=f\times t$$

Here f is 1/3, 1/4 or 1/2. The usual slip is entering 3/4 in for plywood sold as 3/4 in, which often measures 23/32 in. One-third of 23/32 in is about 15/64 in, not the 1/4 in you would get from the label.

Box joint slots follow the other board, not the one on the sled. The depth is the mating board's thickness plus how far the pins should stand proud for sanding flush.

$$h=m+p$$

An equal half-lap takes half of each board, so the faces finish flush. Boards of different thickness need their own depths, which the Lap Joint Calculator works out, and finger width and count belong to the Box Joint Calculator.

$$h=\frac{t}{2}$$

How the Blade Height Calculator Counts Teeth in the Wood

Freud ties blade height to how many teeth are working at once. A Freud representative on the Fine Woodworking forum recommended half of the carbide tip above the material, which should leave 3 to 5 teeth in the cut for ripping and 5 to 7 for crosscuts and sheet goods.

The first card counts the teeth inside the wood from the arc of blade that passes through the stock. R is the blade radius, t the stock thickness, h the blade height and N the tooth count.

$$n_w=\frac{N}{\pi }\left[\arccos \left(\frac{R-h}{R}\right)-\arccos \left(\frac{R-h+t}{R}\right)\right]$$

That count includes teeth on both the front and back of the blade, and Freud's quote does not say which way it counts. So treat the range as a guide for choosing a blade, not as a pass or fail line.

With a 10 in blade set 1 in high on 3/4 in stock, a 40T blade puts 4.2 teeth in the wood, inside the rip range. A 24T rip blade at the same height puts 2.5 teeth in, and an 80T blade puts 8.3. The card lists which common tooth counts land in range at your height.

What Shows Above the Board and Why It Matters

Raising the blade changes the angle the teeth enter the wood. Near the top face, the tooth path tips down from horizontal by an angle that grows as the blade goes up.

$$\theta =\arccos \left(\frac{R-h+t}{R}\right)$$

In the default setup the teeth meet the top face at 18 degrees. At the saw's full 3-1/8 in height they would meet it at 58 degrees, a steeper downward cut. The second card also shows how much blade stands above the board along its length, 3.12 in here.

$$c=2\sqrt{R^2-(R-h+t{)}^2}$$

SawStop's own manuals do not agree on the limit. The Professional Cabinet Saw manual keeps the top of the blade 1/8 to 1/2 in above the workpiece, while the Industrial Cabinet Saw manual says 1/8 to 1/4 in. The card uses the 1/2 in figure and turns amber above it.

Below 1/8 in, the alert warns that the gullets may stay buried and pack with chips. Stumpy Nubs argues for the teeth fully clear with the bottom of the gullet just exposed. Real kickback and burn risk still depend on the blade's hook angle, sharpness, the wood and the feed, so keep the guard and riving knife in place at any height.

Saw Reach, Dado Stacks and Passes

The third card compares your height with what the cutter can reach. Maker depth-of-cut figures assume the saw's own blade size, and a smaller cutter reaches less by half the diameter difference.

$$r=x_{90}-\frac{D_s-D}{2}$$

SawStop lists 3-1/8 in at 90 degrees, 2-1/4 in at 45 degrees and a 29/32 in maximum dado width on its current PCS product page. An 8 in dado stack on that saw reaches 1 in less, so 2-1/8 in. The DeWalt DWE7491RS is listed at 3-1/8 in and 2-1/4 in with a 13/16 in dado limit.

At 45 degrees the loss is smaller, about 71% of that figure, because the blade leans over as it tilts. Past full reach, the alert switches to cutting from both faces, flipping the board end for end at a little over half its thickness.

For dados, grooves and laps, the first card counts passes instead of teeth. With a plain blade, each pass moves the fence no more than one kerf, so no ridge is left between cuts.

$$P=\lceil \frac{W-k}{k}\rceil +1$$

A 3/4 in dado with a 0.118 in kerf blade takes 7 passes at a 0.105 in fence step. The same slot is one pass with a stack on the SawStop. Fence positions for a centered dado come from the Table Saw Fence Calculator.

A stopped dado has a detail most setups miss. The blade's curve means the cut runs shallow past your stop mark by a ramp length that depends on depth and blade size.

$$s=\sqrt{R^2-(R-h{)}^2}$$

A 1/4 in deep stopped dado with a 10 in blade stays shallow for about 1-9/16 in past the mark. With an 8 in stack it is about 1-3/8 in, so extend layout lines by that much or square the end with a chisel.

Dialing In Height by Handwheel Turns

The fourth card turns the difference between the target and your measured height into handwheel turns. Crank four full turns once, measure the change, and divide by four to get your saw's rise per turn.

$$T=\frac{h-h_0}{u}$$

The 1/6 in default comes from a SawStop PCS owner on Sawmill Creek, who reports 3/4 of a turn moving the blade 1/8 in. At that rate, a blade measuring 3/4 in that needs to reach 1 in takes 1.5 turns up.

Rise per turn varies from saw to saw, so measure your own. When the blade is too high, the card says to go down, then up, because finishing on an upward turn takes the gear backlash out.

The calculator accepts stock from 1/32 in to 12 in and up to 6 in showing above it. Blades run from 4 to 16 in with 2 to 200 teeth, and kerf from 0.03 to 1 in. A custom dado depth must stay below the stock thickness, and a kerf wider than the slot flags that the blade cannot cut it.

Setup Slips at the Table Saw

Measuring to a tooth that is not at the top of its arc reads low. Rotate the blade by hand until one tooth sits at top dead center, then measure from the table to that tip.

Setting height on a downward turn lets the blade creep. A LumberJocks thread on a blade that would not hold its height traces the problem to backlash in the screw threads.

Leaving the blade high after a thick cut is the third. A WOODWEB case describes an operator cut while drawing his hand back, with the blade still raised from an earlier thick board.

What Woodworkers Ask About Blade Height

How high should a table saw blade be above the wood?

Makers do not give one number. SawStop's PCS manual allows 1/8 to 1/2 in, its ICS manual 1/8 to 1/4 in, and the Delta manual quoted on WOODWEB says about 1/8 in. Freud frames it as half a carbide tip, roughly 1/8 to 1/4 in on its blades.

A practical way through is to raise the blade until the teeth clear the top face and the gullet bottoms just show. Then check the tooth count for your blade in the first card, and go lower on thin stock.

Is a higher blade safer or more dangerous?

Both sides have a point. A low blade exposes less steel if a hand slips, while a high blade cuts more downward and runs cooler. Stumpy Nubs notes that the worst kickback comes from the back teeth lifting the board, and a fully raised blade still has back teeth to do that, with more steel exposed.

That is why the calculator flags anything over 1/2 in above the stock. The riving knife and guard matter more to kickback than a small change in height.

How deep should a dado be for a shelf?

One-third of the side's thickness is the common choice, and half is the usual ceiling. On 3/4 in stock that means 1/4 in, or 3/8 in at most. Some Sawmill Creek builders go as shallow as 1/8 in when the shelf is also screwed or nailed.

Deeper dados weaken the side along the cut, and cupped boards may need a little extra depth so the shelf still seats. The dado card shows the wood left under the cut for each rule.

Does blade height change tearout on plywood?

It changes which face tears. One Wood Talk Online member's rule is to raise the blade if the top face tears out and lower it if the bottom face does. A higher blade enters the top veneer at a steeper angle, which is the angle the second card reports.

A zero-clearance insert and a high tooth count help more than height alone. Plywood is also where the 5 to 7 tooth crosscut range applies, so check the first card with Crosscut Through selected.