Your Strength attribute determines the total weight you can carry unhindered.
Your carrying capacity is measured in pounds (lbs) and is your Strength attribute multiplied by 15.

Pushing, Dragging, Lifting

You can push, drag, or lift a weight in pounds up to twice your carrying capacity (or 30 times your Strength attribute). While pushing or dragging weight above that of your carrying capacity, your speed drops to 5 feet.

Size and Carrying Capacity

Larger creatures can bear more weight, whereas smaller creatures can carry less. For each size category above Medium, double the creature's carrying capacity and the amount it can push, drag, or lift. For a Tiny creature, halve these weights.

Over Encumbered

If you are carrying above your carrying capacity, your movement is reduced to half of its original value. If you are carrying more than 1.5 times your carrying capacity, your movement is reduced to 5 feet. If you are carrying more than 2 times your carrying capacity, your movement is reduced to 0.

Note: During specific moments, your GM may have you make an Athletics check to overcome these standard values, such as trying to catch a friend who has fallen off a cliff, and drag them up to safety.