Bandsaw Blade Length Calculator
Calculate the bandsaw blade length you need from the wheel diameters and the distance between wheel centres, for equal or unequal wheels, in millimetres, inches and feet-and-inches.
How it works
equal wheels: L = 2C + πD · unequal wheels: L = 2C + π(D₁ + D₂) ÷ 2 + (D₁ − D₂)² ÷ 4C · C = distance between wheel centres at mid-tension
A bandsaw blade wraps half of each wheel and runs straight between them, so its length is twice the centre distance plus one wheel circumference (for equal wheels). With unequal wheels — common on some three-wheel and metal-cutting saws — the arcs are averaged and a small correction is added, the same as an open belt drive. Measure the centre distance with the tensioning wheel halfway through its travel so the blade can be tightened or loosened; manufacturers quote blade length with about ±1 in (25 mm) of tolerance. Round to the nearest length your supplier welds.
Worked example
A 14-inch bandsaw has 356 mm wheels with centres 629 mm apart at mid-tension: 2 × 629 + π × 356 = 1,258 + 1,118 = 2,376 mm, which is 93.6″ or 7′ 9.6″ — the common 93½ in blade.
Sources: Wikipedia — Band saw · Wikipedia — Belt (mechanical): open belt length
Frequently asked questions
How do I measure a bandsaw for a blade?
Set the upper wheel at the middle of its tension range, measure from the centre of one wheel axle to the other (C), measure the wheel diameter (D), then L = 2C + 3.1416 × D.
What blade length does a 14 inch bandsaw use?
Most 14 in cast-iron saws use 93½ in (2,375 mm); with a 6 in riser block they take 105 in (2,667 mm). Always check your saw's manual.
What if the blade is slightly too long or short?
A few millimetres are absorbed by the tensioning screw. If the blade is more than about 1 in (25 mm) off, it may not tension or may not fit over the wheels.
Can I measure an old blade instead?
Yes — mark a tooth, lay the blade flat and roll it along a tape, or cut it at the weld and measure it straight. That is the most reliable figure if the old blade fitted well.
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This calculator is for educational purposes. Double-check important results before acting on them.