Stress Calculator — Average Axial Stress
Calculate signed average axial stress from force and original cross-sectional area, with SI and US units and clearly stated uniform-load assumptions.
Find the average normal stress carried by a cross-section under an axial force. The input force acts perpendicular to that section, and the original area defines engineering stress. Independent force and area units let you use laboratory measurements or nominal dimensions without manually combining conversion factors.
How to use this tool
- Enter the axial force, using positive for tension and negative for compression.
- Choose the force unit; a pound-force is different from a pound of mass.
- Enter the positive original cross-sectional area and its squared unit.
- Choose the stress output unit and inspect the converted force and area.
Formula
σ = F / A₀
σ is signed average axial stress, F is the force transmitted through the section, and A₀ is its original area. One pascal is one newton per square metre. One MPa is also one N/mm².
Example
A tensile force of 10,000 N acts through an original area of 100 mm². Since 100 mm² is 0.0001 m², the stress is 10,000 / 0.0001 = 100,000,000 Pa, or 100 MPa. The same compressive force is entered as −10,000 N and gives −100 MPa.
Frequently asked questions
Is this the maximum stress in a component?
It is a section average. Holes, notches, eccentric loading and contact forces can produce nonuniform stresses. Those effects need geometry and a suitable mechanical model.
Should I use the original or current area?
Use original area for this engineering-stress convention. True stress uses the current area during deformation and is a different quantity, especially when deformation becomes large.
Can this determine a safe load?
The result does not include a material strength, failure criterion, load combination, buckling model or design code. A stress value alone cannot establish component adequacy.
Does a negative answer mean an error?
No. This page uses tension-positive and compression-negative signs consistently. Zero force gives zero average stress; zero area is rejected because division by it is undefined.
Sources
Last updated: 2026-10-30