Table Saw Fence Calculator converts a board's width, a target cut width, and the blade's kerf into the fence position for a rip, an offcut rip, or a centered dado cut, factoring in arbor runout.
Set Your Fence for Rip, Offcut, and Centered Dado Cuts with the Table Saw Fence Calculator
This tool turns your board width, target width, and blade kerf into the exact number to dial into your rip fence. It covers three setups: a standard rip, a reverse rip where you know the offcut width instead, and a centered dado or groove.
Woodworkers use the Table Saw Fence Calculator before ripping stock to width, resawing panels down to size, or centering a dado for a shelf pin line or drawer bottom. It removes the mental math of subtracting a blade's kerf by hand. It also flags cuts too narrow to make safely by hand.
Enter Board Width, Target Width, and Kerf into the Table Saw Fence Calculator
Enter your board's actual measured width, not a nominal lumber size. A "1x6" measures 5.5 inches, not 6. Add your target piece width and your blade's kerf (0.125 in for a standard full-kerf blade, roughly 0.094 in for thin-kerf). The tool works in inches by default, with a metric toggle for millimeters or centimeters.
The Fence-Position Math Behind Rip, Offcut, and Center Cuts
Table saw guides agree on one measuring convention. Run a tape from the fence to the blade tooth closest to it, not the blade's centerline or the saw's built-in ruler. This is the method described in Bob Vila's and This Old House's table saw guides, and it accounts for the kerf automatically.
For a standard rip, where the kept piece stays against the fence, the fence position is simply the target width.
F is the fence position and T is your target piece width. The kerf doesn't move F in this mode. It only reduces what's left on the offcut side.
O is the offcut width and B is the total board width. is the effective kerf. It's the blade's kerf plus any arbor runout you enter.
Runout is a real factor, not a rounding nicety. One breakdown of saw-blade kerf found that a blade with a nominal 0.115-0.125 in kerf can cut a full 0.135 in wide on a saw with noticeable runout. That's enough to throw off a cut list based on the blade's rated size alone.
Sometimes you know the offcut width instead of the target width. That's useful when you need a specific waste-side dimension, like a 2 in strip for a runner. The calculator then solves for the fence position the other way.
F is still the fence position. T here is the offcut width you entered, since the two widths swap roles from the standard rip.
For a centered groove or dado, the fence position splits the board's midpoint and half the kerf. The same setting works whether you measure from either edge.
A common mistake in this mode is entering the dado stack's design width as the kerf without re-measuring. Stacked dado sets change width whenever you add, remove, or shim a chipper.
Every setup guide, from Grizzly's stacking instructions to Woodsmith's dado buying guide, says to measure the assembled stack's actual width before you cut.
The calculator rejects any target width and kerf that would remove more material than the board contains. It shows a geometry conflict instead of a negative or nonsensical result.
It also flags a rip or offcut when the piece against the fence works out to 6 inches or less. That's the point where common shop-safety guidance calls for a push stick.
Exactly how close is safe still depends on your saw's guard, your blade's condition, and your own technique. Treat six inches as a starting point, not a hard rule.
Where to Measure: Near Tooth vs. Far Tooth
The near tooth is the blade tooth closest to the fence. The far tooth is on the other side of the kerf. The calculator's results show both distances so you can verify your setup with a tape measure instead of trusting the fence's built-in scale alone.
Typical Blade Kerf Widths
These are typical widths for common blade types, useful as a sanity check if you haven't measured your own blade yet. Actual kerf varies by blade brand, wear, and your saw's own runout, so measure your blade directly whenever precision matters.
| Blade Type | Typical Kerf |
|---|---|
| Full-kerf blade | ≈0.125 in (1/8 in) |
| Thin-kerf blade | ≈0.094 in (3/32 in) |
| Stacked dado set | 1/4 in or wider, adjustable |
Common Mistakes When Setting Up a Rip or Dado Cut
Some woodworkers trust the saw's built-in fence scale instead of measuring to the blade tooth directly, and that scale drifts out of calibration over time.
Others assume a "standard" 1/8 in kerf instead of measuring their actual blade, even though wear and arbor runout can widen it. And some forget that kerf loss compounds across multiple cuts, coming up short on a cut list that looked fine on paper.
Table Saw Fence Calculator: Common Questions
How do I set the fence for an accurate rip cut?
Measure with a tape from the fence to the tooth on the blade nearest it, not the blade's centerline. This is the convention used across guides like Bob Vila's and This Old House's, and it's exactly what standard rip mode calculates.
Do I need to subtract the blade's kerf when setting the fence?
Not from the fence position itself in a standard rip - only from the offcut side. The kerf still has to be accurate, since it determines what's left on the far side and whether the cut is even possible.
What's a typical table saw rip capacity?
Jobsite saws commonly rip to about 28 inches; full-size saws for most home woodworkers typically reach 30 inches. If your board width is close to your saw's limit, check your saw's spec sheet before relying on the calculator's output.
How do I rip a straight edge without a jointer?
Woodsmith's rip-and-flip method works: set the fence about 1/2 in wider than your target, rip one edge, then flip the board and rip to final width off the newly cut edge.
When should I use a push stick while ripping?
Shop-safety references commonly put the line at 6 inches or less between the fence and blade. The calculator flags this automatically in its rip and offcut modes.
Does the Table Saw Fence Calculator account for arbor runout?
Yes, through the optional runout field under Advanced. Runout adds directly to the blade's kerf, and on a saw with noticeable wobble it can widen a cut by several thousandths of an inch.