Enter the stress range, the material constant K, and the material constant m into the SN Curve Calculator. The calculator will evaluate the SN Curve.

## SN Curve Formula

The following formula is used to calculate the SN Curve.

N = K * S^m

Variables:

- N is the SN Curve (number of cycles to failure)
- S is the stress range
- K is the material constant K
- m is the material constant m

To calculate the SN curve, raise the stress range to the power of the material constant m, then multiply by the material constant K.

## How to Calculate SN Curve?

The following steps outline how to calculate the SN Curve.

- First, determine the stress range.
- Next, determine the material constant K.
- Next, determine the material constant m.
- Next, gather the formula from above = N = K * S^-m.
- Finally, calculate the SN Curve.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem:**

Use the following variables as an example problem to test your knowledge.

stress range = 400

material constant K = 3

material constant m = .25

N = K * S^-m =** ** ?