OSRS High Alch Calculator
Compare a live Grand Exchange price with the high alchemy value.
Profit = High Alch value - GE item price - Nature rune price.
ROI% = profit divided by (GE item price + Nature rune price), multiplied by 100.
A cast also spends one nature rune. Profit over four hours is capped by the buy limit and by how many of the item actually trade.