Donald Trump's executive order providing unemployment benefits will only provide funds for around four weeks. Despite the POTUS' claim that unemployed Americans would receive $400 through the end of the year, the executive order itself tells a far different story. There is a provision in the order which states that the funds will stop being disbursed either after Dec. 6 or after the allotted amount ($44 billion) is used up. Based on current unemployment statistics, around 30 million people are collecting unemployment right now if all these people receive $300 a week from the federal government (states will provide the other $100), that $44 billion will be depleted in around four weeks.
To further break this down, Trump cites both the Robert T. Stafford Disaster Relief and Emergency Assistance Act and the Proclamation 9994 of March 13, 2020, to implement this executive order. On the federal end of things, he is using the Department of Homeland Security's Disaster Relief Fund, which currently sits north of $70 billion. (Note that usual unemployment benefits do not come from this fund, so those remain unaffected.) However, Trump is earmarking $25 billion of that to stay in the fund to assist in possible disaster relief. That leaves $45 billion in play, but Trump's executive order specifically states that $44 billion is the top limit that can be used for this unemployment measure.
"The lost wages assistance program described in section 4(b) of this memorandum shall be available for eligible claimants until the balance of the DRF reaches $25 billion or for weeks of unemployment ending not later than December 6, 2020, whichever occurs first, at which time the lost wages assistance program shall terminate," the executive order, which can be read in full here, states.
So, if you take 30 million people being paid $300 a week in federal funds, the weekly total coming out of this fund is $9 billion. If you take $44 billion and divide it by that weekly $9 billion, that means around 4.8 weeks of funding will be available. Worth noting, to keep up with the promise of funds coming through the end of the year, there would need to be around 20 weeks of funding ($180 billion.)
It is also worth noting that experts have doubts that the unemployment funds could even begin to roll out within the next few weeks, due to its unusual structure. Furthermore, these funds will not come at all if Congress passes a new stimulus package. The order reads: "The lost wages assistance program shall terminate upon enactment of legislation providing, due to the COVID-19 outbreak, supplemental Federal unemployment compensation, or similar compensation, for unemployed or underemployed individuals."