Bias Tape Calculator
Built by Johnny Alto · free, no sign-up · updated July 26, 2026
Bias tape is cut on the diagonal so it stretches around curves, and it comes from a surprising amount of fabric. Switch modes to size the fabric square for a length of bias you need, or to find how much continuous bias tape a square of fabric will yield.
Cut a fabric square of0inches per side
Continuous bias from a square yields roughly the square's area divided by the strip width. This includes a small margin for the diagonal ends. Round the square up to a size you can cut, and remember bias strips are joined on the diagonal, so a little length is lost at each seam.
How much fabric does bias tape take?
Bias tape is cut at 45 degrees to the grain so it has stretch and hugs curves, which is why you cannot just cut it along a straight edge. The continuous-bias method turns a square of fabric into one long strip, and the amount it yields is close to the area of the square divided by the width of your strip. So a length of bias times its width tells you the fabric area you need, and the square root of that area is the side of the square to cut.
This calculator works both directions: give it a length of bias you need and it sizes the square, or give it a square you have and it estimates the bias you will get.
Practical tips
Two and a half inch strips make standard double-fold bias tape once folded; narrower strips make finer tape. Round the square up to a size you can comfortably cut and handle, since the math is an estimate that includes a small margin for the angled ends. Remember that bias strips are joined with diagonal seams, and each join eats a little length, so err on the generous side for a long binding.
Frequently asked questions
How much fabric do I need for bias tape?
Multiply the length of bias you need by the strip width to get the fabric area, then take the square root for the side of the square to cut. 100 inches of 2-inch tape needs about a 15-inch square.
How much bias tape does a square of fabric make?
Roughly the square's area divided by the strip width. An 18-inch square cut into 2-inch strips yields about 162 inches, or 4.5 yards.
What width should I cut bias strips?
Two and a half inches makes standard double-fold bias tape once folded. Cut narrower for finer tape and wider for a bolder finish.
Why cut on the bias at all?
Cutting at 45 degrees to the grain gives the strip stretch, so it curves smoothly around necklines, armholes, and rounded edges without puckering.
More calculators
This calculator gives estimates for planning only; always confirm against your own measurements and species research. Some links are to our buying guides, which contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
← All calculators · Buying guides · About · Affiliate Disclosure · Privacy Policy