Ruler Line Markings ?
 

First let me say it is great to be back amongst you all!! I have never been good at fractions but I need to cut my squares 8 7/8. My mat is done in 1/4" markings but I did find a fiskars mat that has all the marking lines between the inches.Where do I need to cut??

Sounds like you're making half-square triangles?? I would cut my squares at 9" and then trim the finished HST's to the proper size.

But back to your original question...if you're cutting at a 7/8" marking it would generally be the small line just prior to the next inch line. Provided your ruler/mat is marked with 1/8" lines. If there are 8 smaller lines between the 2 inch marks, you are good.

if the 7/8" is for HSTs, most folks cut to the next whole inch and trim/square up the HST after sewing and pressing.

THere are eight 1/8s in an inch. Count over seven 1/8s starting at the inch line. (three lines from the 1/2 line) I have a handy ruler that measures in 7/8s. It sure saves a lot of miss cuts for me. https://www.youtube.com/watch?v=u0clbpGShbc

I also recommend using your ruler markings, rather than your mat markings to measure. I have found results to be more consistent and accurate this way.

I never use my mat for measuring. Always the ruler. Cut them 9 inches and then square up if you're making half square triangles.

I agree with the rest of the members-if you are making half square triangles, just cut them 9". It is better to have it a little bigger than to have it too small. Then you can just trim down.

I found trimming down HSTs are much easier using the Block Loc ruler. No mistakes. I don't like to trim but unless the cutting and sewing are perfect it's easier in the long run to oversize and trim.

Thank you everyone! I will cut to 9 inches & trim down.