Calculate drawing force, mean circumference, thickness, or tensile strength from any three values with inches, psi, N, lbf, or metric units.

Drawing Force Calculator

Enter any 3 values to calculate the missing variable

Drawing Force Formula

The calculator uses the drawing force relationship between mean circumference, material thickness, and tensile strength. In base units, length is converted to inches, tensile strength to psi, and force to lbf.

F = C*t*S
  • F = drawing force, in pounds-force (lbf)
  • C = mean circumference, in inches (in)
  • t = thickness, in inches (in)
  • S = tensile strength, in pounds per square inch (psi)

If you enter any three values, the calculator rearranges the same formula to solve for the missing value.

C = F/(t*S)
t = F/(C*S)
S = F/(C*t)

The calculator functions as follows:

  • Drawing force: multiplies mean circumference, thickness, and tensile strength.
  • Mean circumference: divides drawing force by thickness times tensile strength.
  • Thickness: divides drawing force by mean circumference times tensile strength.
  • Tensile strength: divides drawing force by mean circumference times thickness.

Common Unit Conversions for Drawing Force Calculations

Use these conversions to check how entered values are converted before the formula is applied.

Quantity Unit Base-unit conversion
Length 1 ft 12 in
Length 1 cm 0.393701 in
Length 1 m 39.3701 in
Pressure 1 MPa 145.038 psi
Force 1 N 0.224809 lbf
Input change Effect on drawing force
Double the mean circumference Drawing force doubles
Double the thickness Drawing force doubles
Double the tensile strength Drawing force doubles
Reduce thickness by 25% Drawing force is reduced by 25%, if other values stay the same

Example Problems

Example 1: Calculate drawing force

You have a mean circumference of 10 in, a thickness of 0.05 in, and a tensile strength of 60,000 psi.

F = C*t*S
F = 10*0.05*60000 = 30000 lbf

The drawing force is 30,000 lbf.

Example 2: Calculate thickness

You know the drawing force is 18,000 lbf, the mean circumference is 12 in, and the tensile strength is 50,000 psi.

t = F/(C*S)
t = 18000/(12*50000) = 0.03 in

The thickness is 0.03 in.

FAQ

What is mean circumference in a drawing force calculation?

Mean circumference is the average circumference of the drawn section used in the force estimate. For a circular shape, circumference is based on diameter. In this calculator, mean circumference is treated as a direct input, so you should enter the appropriate average circumference for the part or material being drawn.

Why does tensile strength affect drawing force?

Tensile strength represents the material stress level used in the calculation. A stronger material generally requires more force to draw, assuming the same circumference and thickness. Since the formula multiplies by tensile strength, a higher tensile strength produces a higher drawing force.

Why must exactly one field be blank?

The formula has four variables. To solve for one unknown, the other three values must be known. If more than one field is blank, there is not enough information. If all four fields are filled, there is no missing value to calculate.