My app is called Convert-It. It is a scale conversion calculator but has features of specific use to the modelling community. The main features would be:
A selectable list of popular scales
An option to define your own scale
Entry of a single, or a list of dimensions
A results page
An option to save the results for future use under a chosen name
An option to forward these results to an e-mail address or share on social media (??)

So, you can select a scale - probably HO, O, OO, S, N, TT (if railroad option) or (1:144, 1:87, 1:76, 1:72, 1:25, 1:48, 1:32) if scale modelling option. You then enter the data, hit GO and out comes the result in imperial or metric. You can also enter your own scale or enter the Unit and the data to find out the scale.
On the second page you can enter a list of measurements and touching Go will see a list of conversions based on the parameters on the previous page.
Now, there are lots of holes in this as I don't have days to work it out, just hours, so please don't start telling me what I have missed. What I would like is comments as to how useful you might find this tool.
My tutor is only interested in that feedback so anything else would be dropped from the final submission.
It would be good if two or three people could give me their ideas.
I will also be posting this on other forums to widen the feedback.