UntilSince is a free and open-source date-tracking app, currently in development. With it you never lose track of how much time there is until or since a specific date.
Check out the latest version of the project:
git clone https://git.davidwalter.at/divadretlaw/UntilSince.git
In the UntilSince directory, check out the project's dependencies:
cd UntilSince carthage update --platform iOS --cache-builds
Build and run the "UntilSince" scheme.