Weights & Measures - convert just about anything, but you have to do the math.

Platen Tonnage Chart -A chart listing common platen sizes to tonnage at 2000 psi

Platen Tonnage Calculator - Insert ram diameter and platen size, this will calculate the PSI

Pressure Calculator - Convert PSI to numerous other what EVER

Decimals - Fractions - Common fractions of an inch - decimal & metric equivalents