Just clarifying, you’re asking for the exact IAS Mach speed? If so, there isn’t one because of your current position and speed relative to Mach, which is a function of the environment you’re passing through. The difference isn’t much, 1-3 knots for most short-medium hauls.
The higher you go, the more important it is to know what speed you’re at in relation to Mach. At 10000, commercial aircraft won’t be anywhere close, so an IAS is fine. Above FL280, you’re in an environment where Mach effects can start to cause issues to your plane, so the speed is given in relation to Mach and no longer in knots.
If you’re asking for plane cruise speeds, they’re listed around here and on other pages like SimBrief for different aircraft.