What? No, it's not. Those forms are not calculating what you think they are. To calculate the psi for a press...multiply your number of ton by 2000 (if US tons) - this gives your total pressure in lbs. Then, divide that number across the total number of square inches of whatever surface is taking the pressure (usually a rosin bag). That's why I asked what size bags you use. If your press is operating at 5 t (US) and your plates are 3x5, you'll have a psi of 666 (5x2000/15), if something fully covers the face of the plates. But, if your bags are 2x4, your psi is 1,250 (5x2000/8 ), regardless of the size of your plates...because the 10,000 lbs of pressure is spread over 8 inches, not 15. This means that on any press, if you increase the size of the plates, you decrease your maximum possible psi. This is part of the reason I like a 12 t H-frame: I can swap between 3x5 and 4x7 plates and keep my psi constant...or vary it, depending on the quantity I want to press at any one time and the source material I'm pressing (flower or kief). Without that extra headroom (and the ability to swap plates), I just wouldn't have that kind of flexibility to dial things in the way I like.
