Enter the metal weight loss, the metal density, the exposure time, and the exposed area into the Corrosion Rate Calculator, selecting the appropriate units for each. The calculator will evaluate the corrosion rate (penetration rate) and can also solve for one missing value when the other four are provided.

Corrosion Rate Calculator

Calculate corrosion penetration rate directly from coupon test data, convert rate units, estimate thickness loss, or estimate annual corrosion cost.

Corrosion Rate
Unit Converter
Thickness Loss / Life
Cost of Corrosion

Corrosion Penetration Rate

Primary workflow for most visitors. Enter coupon test data and get corrosion rate in mm/year, mpy, μm/year, and mil/year.

Direct Weight Loss
Initial / Final Weight

Corrosion Rate Formula

The following formula is used to calculate the Corrosion Rate.

CR (mm yr⁻¹) = 87.6 × W / (D × A × t)
  • W = metal weight loss (mg)
  • D = metal density (g cm⁻³)
  • A = exposed area (cm²)
  • t = exposure time (h)

How to Calculate Corrosion Rate?

The following two example problems outline the steps and information needed to calculate the Corrosion Rate.

Example Problem #1

  1. First, determine the metal weight loss (mg).
    • The metal weight loss (mg) is calculated to be: 50.
  2. Next, determine the metal density (g/cm³).
    • The metal density (g/cm³) is measured to be: 10.
  3. Next, determine the exposed area of the sample (cm²).
    • The exposed area of the sample (cm²) is found to be: 3.
  4. Next, determine the exposure time (h).
    • This is given as 265 hours.
  5. Finally, calculate the corrosion rate using the formula above:

CR = 87.6 × W / (D × A × t)

The values provided above are inserted into the equation below and computed.

CR = 87.6 × 50 / (10 × 3 × 265) = 0.5510 (mm/year)


Example Problem #2

The variables required for this problem are provided below:

metal weight loss (mg) = 60

metal density (g/cm³) = 4

area of sample (cm²) = 5

time (hours) = 200

Test your knowledge using the equation and check your answer with the calculator.

CR = 87.6 × W / (D × A × t) = (mm/year)