This app was mentioned in 2 comments, with an average of 2.00 upvotes
Get a BTC calculator: https://itunes.apple.com/us/app/bitcoin-convert/id862914093?mt=8 https://play.google.com/store/apps/details?id=io.bitkoinio&hl=en or use: https://coinmarketcap.com/calculator/
Then set alerts on Blockfolio.