What is a poundal (pdl)?
A poundal is a unit of force in the foot-pound-second (FPS) system. It is the force needed to speed up a 1-pound mass by 1 foot per second squared (1 ft/s²). Poundals show up most often in older physics and engineering work.
What is a kip?
A kip is a unit of force equal to 1,000 pounds-force (lbf). It’s used a lot in structural engineering in the US. You’ll see kips for loads on beams, columns, and connections.
How do poundals and kips compare?
Poundals and kips both measure force, but they come from different force definitions. The poundal is tied to pound-mass and acceleration. The kip is tied to pounds-force and is scaled up by 1,000.
What is the conversion from poundals to kips?
Use this relationship:
- 1 lbf = 32.174049 poundals (pdl)
- 1 kip = 1,000 lbf = 32,174.049 pdl
- 1 pdl = 1 / 32,174.049 kip ≈ 0.000031082 kip
How do I convert poundals to kips?
Multiply poundals by the kip-per-poundal factor:
- kips = poundals ÷ 32,174.049
- kips = poundals × 0.000031082 (rounded)
Example:
- 64,348.098 pdl ÷ 32,174.049 = 2.000 kip
How do I convert kips to poundals?
Multiply kips by poundals per kip:
- poundals = kips × 32,174.049
Example:
- 0.5 kip × 32,174.049 = 16,087.0245 pdl
Why does the number 32.174 show up in this conversion?
32.174049 is the standard gravity value in feet per second squared (ft/s²). It links pound-mass and pounds-force in the FPS system. That link is why poundals (based on acceleration) convert to pounds-force, and then to kips.
Is a poundal a unit of mass or force?
A poundal is a unit of force. It can look confusing because it uses the word “pound.” In FPS units, pound-mass (lbm) is mass, pounds-force (lbf) is force, and the poundal (pdl) is also force.
Are poundals still used today?
Poundals are rare in modern practice. Most US engineering work uses lbf and kips. Poundals may still appear in older textbooks, notes, or legacy calculations.
What’s the difference between lbf and kip?
Both are force units. The kip is just a larger unit:
This makes big loads easier to read and write.
How many poundals are in 1 kip?
There are 32,174.049 poundals in 1 kip. If you only need a quick estimate, you can use 32,174 pdl per kip.
How do I round poundals to kips without losing accuracy?
Use more digits during the math and round at the end. For many engineering uses, rounding to 4 to 6 decimal places in kips is enough, but it depends on your tolerance and load size.
What units do I need to watch when converting poundals to kips?
Confirm you are working with force, not mass. Poundals convert to kips through pounds-force. If your value is in pound-mass (lbm) or comes from mass times acceleration in mixed units, fix the units first.
Can poundals to kips conversions be negative?
Yes. Force can be negative if it points in the opposite direction of your chosen sign. The conversion factor stays the same; only the sign carries through.