I know the App “InfoZone” from Hanita it´s a good Tool what i used with my iPhone. What i like is you can calculate the Job and sende it your selve per email. It calculates the amount of roll‘s You need for the job. I tried also excel bud i can’t figured out the lenght and amount of (30,5m) roll’s. So for my daily Business jobs i calculates with excel for Square Meters for the Film and lenghts meter for the sealing. This year we finished our biggest Job here in good Old Germany with 2500 qm sunprotection external Film. We had luck on it because we had all the same size of windows. Bud we have to remove first the old one‘s. The rolls were precuted all to the same size so we only have to cut the lenght for each Window. The Building has 17th storeys and only one!! External Lift that only two guys can work at the same time. I take a Look to mr.excel but there is nothing for me. Sorry for my bad english. I send you some pictures of the job on Pinterest. https://pin.it/b6ilc4ebpwkwfe https://pin.it/eo2vcirjjk5iz3 https://pin.it/ricxcg7cngwf27 Have a nice day.