Oh wow! I really like this, and wanted to create something like this for myself.
The interface works, but it’s confusing. A simpler, graphical interface would be great (something like http://howmuchtomakeanapp.com would be ideal)… but this works great as an MVP. And I’d rather see you focus on nailing down the math first before the pretty graphics & forms!
I love that you’ve included support time cost! That’s the main feature I wanted to include when creating my own spreadsheet / calculation of this. I felt it glossed over the “time spent on business” though, and 5 hours a month seems crazy low (even Tim Ferriss had a Four Hour Work Week!) I’d like to see that broken out a little more, ie time spent on blogging/marketing, time spent on maintenance/upgrades, and then there’s the icky accounting / paperwork stuff. That’s probably too much detail for some, so a way to switch between hyper-detail and overall ballpark numbers would be good.
It does go pear-shaped for me after the advertising calculation though. I’ve spent enough on Adwords & FB to know that it’s mostly a waste of money, so I want to set my number of customers who arrive via ads as zero %… but then I get lots of NaN everywhere. I need to set my CPC at $0 before I get sensible numbers again. (And 20% of clicks becoming customers? That seems crazy high… I’d be more likely to set that at 1%, or even sub 1%.)
One last thing missing is the e-commerce cut and any VAT. Google / Apple would be 30%, whereas FastSpring is ~6% and Paypal/Stripe would be ~3%. VAT/GST would be anywhere from 0 - 25%, I think. (And if you really want to make hearts sink, add in personal/business tax rate, some of that “profit” goes to the taxman.)
But well done, I really really like this. I’d mostly use it to scope back the time spent on development to hit a specific price point (eg how much development time can I afford to spend to hit a $50 price).