Micrometer Simulator
Rotate the thimble to set a measurement, then read it off the sleeve and thimble scales. Watch the half-millimetre line, switch the least count, add a zero error, and practise with instant feedback — free and 100% in your browser.
How to Read a Micrometer
ToolsPix Micrometer is a free, interactive micrometer (screw gauge) simulator that runs entirely in your browser. It is drawn with lightweight SVG and a little geometry, so there is no software to install, no account to create, and nothing is ever uploaded to a server.
Why use the ToolsPix Micrometer Simulator?
- Completely free with no sign-up, watermark, or usage limit.
- Runs entirely in your browser — nothing you do is ever sent to a server.
- Switch between a 0.01 mm micrometer, a 0.001 mm vernier micrometer and a 0.001 inch micrometer to match your real instrument.
- Breaks every reading into the sleeve part, the half-millimetre line and the thimble part so you can see how it is built.
- Includes a zero-error switch and a practice mode with instant scoring for revision.
Steps to read a micrometer
Drag the thimble to set the spindle, or switch to Practice for a random measurement. Read the sleeve first — take the largest whole-millimetre mark the thimble has uncovered, then add 0.5 mm if a half-millimetre line is exposed below the datum. Next read the thimble division lined up with the datum line and multiply it by the least count, and add the two parts together. If a zero error is set, subtract it to get the corrected reading, and press Reset to start again. Once the page is loaded, the tool also works completely offline.
FAQ
How do I read a micrometer?
First read the sleeve: take the largest whole-millimetre mark uncovered by the thimble edge, then check the row below the datum line — if a half-millimetre mark is also exposed, add 0.5 mm. Next read the thimble: the division lined up with the datum line gives the hundredths, so multiply it by 0.01 mm. Add the sleeve and thimble parts together to get the full measurement.
What is the half-millimetre line on a micrometer?
A standard metric micrometer has a 0.5 mm screw pitch, so the sleeve carries whole-millimetre marks above the datum line and half-millimetre marks below it. The half-millimetre marks are the classic trap: if one is exposed past the thimble edge you must add 0.5 mm to the reading. This simulator highlights the exposed half-millimetre line so you never miss it.
What is the least count of a micrometer?
The least count is the smallest length the micrometer can resolve. On a standard metric micrometer the 0.5 mm pitch is divided into 50 thimble divisions, giving 0.01 mm. This tool also offers a 0.001 mm vernier micrometer and a 0.001 inch micrometer, so you can practise on the type you actually use.
How do I correct a micrometer zero error?
Close the micrometer fully and read the scale: if it does not sit exactly on zero, that offset is the zero error. A positive zero error is subtracted from every reading and a negative zero error is added back. Turn on the zero error switch in this simulator to see the observed reading, the error and the corrected value side by side.
Is the micrometer simulator free and does it work offline?
Yes. The micrometer simulator is completely free with no sign-up, and every calculation runs locally in your browser with JavaScript. Nothing is uploaded to any server, and once the page has loaded it also works completely offline.