You can Google: Basement Floor Jack.

Ahhh thanks. I would have never thought of that. Anyone else know the standard lbs load?

The first hit at HomeDepot.com says 9100 lbs. it varies from manufacturer to manufacturer.

Ah ok, i see my question is perhaps not worded great. I realize jack posts come with various load capacities. When an engineer designs a house she needs to calculate the load barring capacity for each post based on the weight of the house and span and height of the posts. However, I also know that hardly anyone goes though this math when they build (just like we don't for determining the span of 2x4 it's standard to use 16 inch). Post and beam construction also has this type of standard. given the standard span of 9 ft and 7ft height, i'm looking for the standard load bearing capacity for the post. I'm pretty certain it's over 9100. That's a temporary "light duty" 2 part adjustable post for sure.

Ok so incase anyone pulls this up on a google search looking for the same info. I 6x6 wood post is (or was) normally used and the psi for different woods is

The compressive strength of (wet to dry)

Douglas Fir is 1300 - 1700 psi

Hemlock, Western is 1300 - 1650 psi

Pine, Eastern white is 960 - 1200 psi

So you can do the calculations or see here they say 26k lbs. https://courses.cit.cornell.edu/arch264/calculators/example7.1/index.html

other good info on that page.