Laser-Cut Postage Size Gauge/Guide

If you sell things and post them via Royal Mail in the UK, there are lots of different standard sizes for letters, packets and parcels, and they all cost different amounts depending on the weight.

Currently (April 2018) something counts as a Large Letter if it is less than 35.3cm long, 25cm wide, and 2.5cm thick. (If you’re reading this after April 2018 you can check the Royal Mail price finder to see what the current postal options and prices are), and here are the size and weight formats.

I’ve just started selling things on ebay again, and have to check whether my packages fit the standard ‘Large Letter’ criteria or not when I’m mailing them.

Rather than measure each package or envelope individually with a ruler, I’ve made a handy gauge with the laser cutter, so that I can quickly see whether the package counts as a large letter and then pay the correct amount. I cut a ‘postage gauge’ from a sheet of 3mm MDF with the laser cutter, with dimensions of 35.3cm x 25cm. So all I have to do to see if my package fits within the large letter dimensions is put it on top of the MDF piece. If I can still see the MDF around all sides of the package then it’s OK for a large letter, but if the package is too big to see all of the MDF sheet then I know it’s probably going to be a ‘small parcel’ instead.

laser-cut postage size gauge - envelope too big
Length of envelope is fine, but it’s too wide

Then to check the thickness of the envelope/package, I cut a slot in the MDF that was 25cm x 2.5cm. So now I can slide the envelope/packet through the slot to check that it is less than 2.5cm.

laser-cut postage size gauge - large letter size

laser-cut postage size gauge being used - large letter
laser-cut postage size guide being used

I’ve included a free PDF ‘postage gauge’ file below, just in case you’ve got a laser cutter and would like to make your own. (NOTE: For this one I’ve made all of the measurements about a millimetre smaller than the real-life measurements, just to be on the safe side! So I know that if my envelope fits through the slot that is 2.4cm x 24.9cm, it should definitely count as being within 2.5cm x 25cm. Having said that – do check (1) that the Royal Mail’s standard measurements are still correct if you’re reading this after April 2018, and (2) that the gauge/guide that you have cut actually has the correct dimensions in ‘real life’. I take no responsibility for other people not working out their postage costs correctly!)

PDF file:

laser-cut postage size gauge

free template for laser-cut postage size guide
Free PDF laser cutting file


If you download and make the size gauge/guide, let me know how it goes! You can use the comments form or the Contact Us page, or tweet me @LaserSister