Software to calculate n-UP

I often get customers who call to get quotes for custom sized cards, inserts and labels etc... Then I'd open up an SRA3 sheet in inDesign, draw the rectangle and then place it on the SRA3 sheet to see how many i can get up. Once that's done can I only calculate sheets required and other costs.

Im not sure if there is something available to automate this quickly? I've put a small PC app together to do it and it works like a charm. I also intend adding a few additional features based on my requirements. If anyone would like to use / test it let me know and i'd love to get some feedback on upgrading it and feature requests.

 

What about gutters?

 

AFAIK margin and gutter is the same thing

 

Nope.

Margins are on the outside of the sheet. Gutters are in-between the images. ie zero margins so it will print as close the edge as possible and 4mm gutters to accommodate the crop marks and bleed for the maximum coverage