Thanks for the feedback. I never said I am not going to add. This is the only reason I shared it here so that I can get some help in adding more units.
I have already added football field in length category. Will add more soon.
I just googled it after your comment and the conversion of football field came in terms of acre or hectare so I think Area is suitable. I will see what most people are using and based on that I will set its value.
Most of units contain very generic description because my goal was to work on the tool rather than the content part. But I will optimize it in the upcoming future since I am one guy managing everything.
Thanks for appreciation. Actually, user does not cover all units. It only shows most common one in terms of length. There are various units in terms of weight, area, and length that are used on regional level. If you just look at the area and length category dropdown, you will be suprised.
I will add it by today. It will be available in Area category by tomorrow. Thanks for letting me know. I just add units as soon as somebody let me know by twitter or email.