If you need a one-stop shop for various Old School Runescape calculators then this is the app for you.
It will provide the amount of actions required to get to a specific goal (level or XP) and it uses real time prices to calculate the profit or loss.

For smaller phones, you can hide certain fields, such as the XP of an action, which will free up space and allow the text of the other fields to increase.

You can check the high scores of an account and also turn on the progress bars to see how close you are to the next level - this uses their current experience against that of the next level, and produces an Red/Amber/Green colour based on the % filled.

There is an XP table just in case you need to check what you need for a specific level.

Last but definitely not least is the grand Exchange lookup.
This has a list of all items available in the GE and will return the following:
- members icon
- examine text
- GE buy limit
- High alch price
- current price (both high and low values)
- price in the last 1 hour, 6 hour and 24 hour.