Terminal Velocity Calculator

In short Terminal velocity is the speed at which drag exactly cancels weight, so the net force is zero and nothing accelerates further: v = √(2mg ÷ ρCdA). For an 80 kg skydiver with a drag area of 0.49 m² that is 51.1 m/s, or 184 km/h — the familiar belly-down figure. This page prints the drag force and the weight side by side at that speed so you can see them balance, because that balance IS the definition and the formula is only it rearranged. Two things surprise people. Terminal velocity is never actually reached: speed approaches it exponentially, arriving at 95% after 9.55 seconds and 310 m of fall, and never quite getting there. And the scaling is square-root, not linear — halving your drag area raises the speed by 41%, not 100%, and four times the mass only doubles it. That square root is why a heavy object falls faster in air even though mass cancels in a vacuum, and why a skydiver pulling into a tight position speeds up much less than it feels. The honest caveat is that the drag coefficient and the area are not separately knowable for an awkward shape like a person; only their product is constrained. Quoting a drag coefficient to two decimals while guessing the area is false precision, which is why the page reports the product.