Just watching the US Election coverage on Yahoo how many votes do they have to get to win? (I'm in Australia)?

It is not the number of votes cast which decide the president it is the number of electoral college votes each candidate gets.  So like 2016 the person with the most votes by almost 3 million, does not automatically mean they not win the election.

Depending on the population of each states determines how many votes in the electoral college they have.

The magic number of electoral votes a candidate needs to win is 270, at this moment Biden has 238 to Trump 213.

270 electoral votes, in our flawed electoral college system, we don’t elect POTUS by the national popular vote. There are less than 100 electoral votes available in this election. FYI, fun fact, the 538 electors, once certified, can literally pick anyone they want to be POTUS, as long as they meet the bare minimum requirements. Me for example. The Constitution created the electoral college to “protect us” from demagoguery, you can see how that worked out.

Trump needs 270.  If you do NOT watch the very liberal United States media, you will learn that he already has more than that

28 RED STATES: (22 blue or undecided states, D.C. is blue also)

4 Idaho

3 Montana

3 Wyoming

6 Utah

3 N. Dakota

3 S. Dakota

5 Nebraska

6 Kansas

7 Oklahoma

38 Texas

6 Iowa

10 Missouri

6 Arkansas

8 Louisiana

10 Wisconsin

6 Mississippi

16 Michigan

11 Indiana

8 Kentucky

11 Tennessee

9 Alabama

18 Ohio

16 Georgia

29 FLorida

20 Pennsylvania

5 W. Virginia

15 N. Carolina

9 S. Carolina

TRUMP = 288 ELECTORAL VOTES

( SOURCE: https://www.bbc.com/news/election-us-2020-54783016 )

270 electoral votes to win.