Strain converter
Convert how far a material stretches between microstrain, percent and millimeters per meter.
That's 2.1× as much stretch as steel warming by 40 °C, while mild steel starting to yield is 1.4× more. A 10 m bar would stretch by 10 mm.
What it means
How much stretch is that?
Material figures are typical. Steel yield depends on the grade; concrete cracking on the mix and age.
Every unit
Your strain in every unit
Learn
Three things worth knowing
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1,000 µε = 0.1% = 1 mm/m
A 10 m steel beam at 1,000 microstrain has grown by 10 mm. Everyday structures work in hundreds of microstrain, never whole percent.
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Why it is dimensionless
Stretching a 1 m bar by 1 mm and a 1 km cable by 1 m is the same strain, 0.001, and loads them just as hard. Dividing by the length is what makes one figure fit every size.
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Strain is not stress
Stress is the force per area inside the material; strain is the stretch it causes. The modulus links them, which is why the same stress stretches rubber a thousand times more than steel.
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Popular strain conversions
Background
About strain
Strain is how much something has stretched, as a fraction of its original length. It has no units at all, which is why the same number appears as 0.001, 0.1%, 1 mm/m or 1,000 µε.
Engineers measure it with strain gauges glued to beams and bridges, and read it in microstrain: millionths of the length.