2.89 g per metre of 1.75 mm TPU 95A, taking 1.2 g/cm³ from the middle of its band. A kilogram is 346.46 m, a little more than PLA's 335.28 m.
TPU sits between ABS and PLA on density, which surprises people who expect a rubbery material to be light.
The measurement problem nobody warns you about
TPU stretches. Pull a metre off the reel to weigh it and you have measured a metre of stretched filament, which is longer than the metre that was on the reel and shorter than the length that will feed through the extruder under tension.
For the same reason, a length estimate made by counting turns on a TPU reel is less reliable than the same estimate on a rigid filament. If you need a real figure, weigh the spool rather than measure the filament.
The density band is genuinely wide
TPU 95A is stored at 1.15 to 1.24 g/cm³, and softer grades run lower still — TPU 85A starts at 1.10, and TPE spans 0.90 to 1.20.
That range is wide because "TPU" describes a family rather than a compound. Shore hardness, plasticiser content and additive package all move the density, and two spools at the same stated hardness from different brands genuinely differ.
So the 2.89 g per metre above is a starting assumption, not a specification. For a spool you print a lot of, weigh a known length once.
Why the mass matters less here than usual
Flexible parts are usually small — phone cases, gaskets, feet, bumpers, drive belts — and the cost per print is dominated by print time rather than by plastic, because TPU is printed slowly to keep the extruder from buckling it.
A part that takes two and a half hours instead of one has already spent more on machine time than the extra few grams could ever cost. The grams-per-metre figure is useful for planning how far a spool goes; it is not where the money is.
Put a different Shore grade's density into the length and weight converter to get its own figure. Every stored property for the mainstream grade is on the TPU 95A page.