From the relative sizes of the original Kingom at the time of Phillip II to the expanses Alexander conquered. More like 100x (1000x would cover the whole globe), but 1000x works for emphasis.
You are suggesting that Alexander's empire covered 10% of the globe?
Please check your sense of scale.
The total area of the globe is about 510.1 million km2; the total landmass of earth is about 148 million km2. The Internet tells me that Alexander's empire stretched about 5.2 million km2 at its greatest extent. Which is about 1% of the globe, or 3.5% of the total dry landmass.
For comparison, the Soviet Union had about 22.4 million km2. And the British Empire had about 35.5 million km2 at its largest.
The Internet also tells me that Phillip II controlled about 0.3 million km2 at the end of his reign. Which makes for about 5% of Alexander's territory at the end of his reign. A 20x expansion for Alexander is nothing to sneeze at, but it's a far cry from 1000 or even 100.
Phillip II controlled roughly half of modern Greece size-wise, so 25K sq.m. At best, if we include his later (unstable) expansion territories, like the Peloponnese, he'd be at something like 35K sq.m. Not sure where 0.3M sq. miles comes from (that would be 8 to 12 times the area).
For Alexander the numbers I find are about "two million square miles".
2M / 25K gives 1/80. Round it up to 1/100 and let's call it a day.
1000x was an off the cuff number, with the point being the huge increase in the size of the kingdom Alexander inherited - not the specific multiplier.
