cutting calibration issue: I have co2 laser and on software if i put a queare of 100mm x100mm and after cutting i am getting 101mm x101mm how to calibrate it in light burn ? using RUNDA controler pannel
Hi @Omcarve
For a Ruida controller, do this from LightBurn rather than trying to adjust it from the controller panel.
Go to Laser Tools → Machine Settings, click Read to load the current controller settings, then Save to File to make a backup.
Then use Calibrate Axis for X and Y separately. Enter the requested size, run a measured test cut/mark, then enter the actual measured size. LightBurn will calculate the correction and you can Write it back to the controller.
A larger test, such as 200 mm, is better than 100 mm if your bed allows it, because small measuring errors matter less.
In additon to @Dominic’s suggestions, do not measure cut pieces to calibrate the machine.
The size of a cut piece will always be smaller than the machine movement. Unless you measure and correct for the kerf width in the material, the calibration will be wrong.
Instead, engrave a square on the material and measure center-to-center distances.
You can also use a steel scale:
I like @ednisley tip, marking a square on material rather than cutting through is best practice.
That said, I don’t think I’d ever take the steel scale out of a combination square 
That’s the longest “good-enough” scale I have; its 24 inch / 61 cm length let me run the X axis almost all the way.
In my defense, I matched its marks against what serves as a reference scale around here before depending on it:
Given that I’m a USA-ian, those Rabone Chesterman scales were a surplus find, back when you could get good stuff cheap.
You gotta up your shop tool spend.
They really are beauties. The thing that I find most annoying about British measuring tools today is that one side is metric and the other imperial. Both are useful but I want to keep them separated.
I’ll keep my eyes open. See these are “boot sales” (flea market/yard sales) from time-to-time maybe we can get a pile for bug-finder-general incentives!
Those have the inch scale flipping decimal / fraction divisions and the metric scale flipping 1 mm / 0.5 mm, so you’d love 'em to death.
A while back I stocked up on factory-blem scales sporting inch & metric sides for knock-around shop use. Although I prefer metric for things I make, plenty of stuff was baked with hard-inch dimensions much easier to eyeball against those divisions.
Gotta love it: I’m reusing a manual XZ positioner (from an optics lab haul) made with 4-40 screw holes on 2-5/23 × 1-13/32 inch centers. 
Only for the USA-ian market, back in the day.
Sheesh and similar remarks.