In case you ever need to know this for the future, YES, you can fit $1 million cash in a standard briefcase… but… only if you use hundred-dollar bills. If you only had twenty-dollar bills, you would need seven briefcases.
If you use $100 bills, $1 million would require 10,000 bills (10,000 × $100 = $1,000,000). A single bill measures approximately 6.14 × 2.61 × 0.0043 inches. The stack of 10,000 bills would be about 43 inches tall (10,000 × 0.0043 = 43 inches) if perfectly compressed.
However, when you account for how bills naturally stack (with some air between them), the practical height is closer to 50 inches. A typical briefcase measures roughly 18 × 12 × 4.5 inches internally. While the width and length would accommodate the bills laid flat, the height restriction means you'd need to create several stacks.
You could arrange the money in multiple stacks of about 1,000 bills each (each stack being roughly 4.3-5 inches tall). With this arrangement, you could fit the entire $1 million in $100 bills inside a standard briefcase, though it would be very tightly packed and quite heavy (around 22 pounds).
If you tried using smaller denominations like $20 bills, you'd need 50,000 bills, which would be impossible to fit in a standard briefcase.
$1 Million
$100 Million
$100 million in hundred-dollar bills would reach around four feet if stacked brick-by-brick on a pallet. Actually, around 4.5 feet if you include the height of the pallet. Here's what that might look like, with a 5 foot 5 man for scale comparison:
$207 Million
Back in 2007, DEA agents and Mexican police obtained a warrant to search a suburban home in Mexico City that was believed to belong to a methamphetamine-manufacturing cartel. As they performed the search of the home, they entered a nondescript back bedroom and found $207 million in mostly $20 USD bills stacked neatly in the most beautiful pile you'll ever see:
$207 Million Cash in Bedroom
$1 Billion
Here's what $1 billion in hundred-dollar bills stacked on pallets would look like with an adult-sized dummy for scale:
$1 Trillion
Are you ready to see what $1 trillion dollars would look like? Here it is. The moment of glory. The literal money shot. If you took pallets of cash like the ones above and lined them up to create $1 trillion, this is what it would look like:
Just give me a stack off the back. I'll disappear. You'll never hear from me again.