If Biden were to win every state carried by Hillary Clinton along with the seven battleground states in which he’s currently leading Trump (Arizona, Florida, Michigan, North Carolina, Ohio, Pennsylvania, and Wisconsin), he would walk away with at least a 347 electoral votes. A win requires only 270 electoral votes.

And Biden is tied with Trump in Iowa, and lagging by 1 percentage point in Georgia—a state Democrats haven’t carried since the 1992 general election—according to RealClearPolitics poll averages.

Heading into Election Day in 2016, Clinton led in Trump in Pennsylvania (+1.9 percentage points), Michigan (+3.4 points), and Wisconsin (+6.5 points). Trump won all three.

For Trump to win in 2020, he’d likely need to win at least five of the states in which Biden currently leads: Arizona (+3.4 points), Florida (+1.3 points), Pennsylvania (+4.7 points), North Carolina (+0.8 points), and Ohio (+3.3 points). If he wins those, Trump can likely afford to lose battleground states like Michigan (+5.2 points) and Wisconsin (+7 points) where Biden is currently leading.

Simply put: If Trump doesn’t gain significant ground in the remaining six weeks before Election Day (Nov. 3), he’ll be faced with pulling off a bigger upset than four years ago.

The silver lining for Trump? Like Clinton four years ago, Biden hasn’t topped 50% in most battleground state poll averages. He’s over 50% only in Maine (53.8%), Minnesota (50.4%), and Wisconsin (50.7%). That means there are enough undecided or third-party party voters in most battleground states to potentially swing those states to Trump.

As of Monday, FiveThirtyEight forecast the odds of Biden winning at 78%, while The Economist forecast the Democratic nominee having a 85% chance of winning the electoral college.