Vickers Hardness Number Calculator

What Is the Vickers Hardness Number (HV)?

The Vickers Hardness Number (HV) measures the hardness of a material by pressing a diamond indenter into its surface under a specific load. The indentation left on the material is measured, and the hardness value is calculated based on the applied force and the size of the indentation.

The Vickers test was developed to provide a single hardness scale that works for both soft and hard materials.

Key points about the Vickers hardness test:

• Uses a diamond pyramid indenter
• The indenter has a 136° angle between opposite faces
• Measures the diagonal lengths of the indentation
• Works for metals, alloys, ceramics, and thin materials

The result is expressed as HV, which stands for Hardness Vickers.

Example:

• Mild steel may have 150–200 HV
• Hardened steel may reach 600 HV or higher

What Is a Vickers Hardness Number Calculator?

A Vickers Hardness Number Calculator is a digital tool that automatically calculates the hardness value using the Vickers formula.

The calculator typically requires three inputs:

1. Applied Load (Force) – the force applied to the indenter
2. Diagonal 1 (d1) – the first diagonal of the indentation
3. Diagonal 2 (d2) – the second diagonal of the indentation

Once these values are entered, the calculator determines:

• The average diagonal length
• The Vickers hardness number (HV)
• A basic hardness classification

This removes the need for manual calculations and reduces errors.

Vickers Hardness Formula

The Vickers hardness number is calculated using the following formula:

HV = 1.8544 × F / d²

Where:

• HV = Vickers Hardness Number
• F = Applied load (kgf)
• d = Average diagonal length of the indentation (mm)

Why 1.8544?

The constant 1.8544 comes from the geometry of the 136° diamond pyramid indenter used in the Vickers test.

This constant converts the measured indentation into a standardized hardness value.

How the Calculator Works

The calculator follows several steps to produce the final hardness value.

1. Enter the Applied Load

The applied load is the force used during the hardness test.

The calculator allows different units:

• kgf (kilogram-force)
• N (Newtons)
• gf (gram-force)

If the load is entered in Newtons or gram-force, the calculator converts it into kgf automatically.

Conversion examples:

• 1 N ≈ 0.10197 kgf
• 1000 gf = 1 kgf

2. Enter the Indentation Diagonals

After the indentation is created, the two diagonals are measured using a microscope.

Inputs required:

• Diagonal 1 (d1)
• Diagonal 2 (d2)

These measurements can be entered in:

• Millimeters (mm)
• Micrometers (µm)

If microns are used, the calculator converts them into millimeters.

3. Calculate the Average Diagonal

The average diagonal is calculated as:

Average diagonal = (d1 + d2) / 2

This average value is used in the hardness formula.

4. Compute the Hardness Value

The calculator then applies the formula:

HV = 1.8544 × F / d²

Where d² is the square of the average diagonal.

The result is displayed as the Vickers Hardness Number (HV).

5. Material Hardness Interpretation

Many calculators also provide a basic interpretation of the result.

Typical ranges include:

This helps users quickly understand the hardness category of the tested material.

Step-by-Step Example

Let’s see how the Vickers hardness number is calculated.

Given:

• Load = 10 kgf
• Diagonal 1 = 0.50 mm
• Diagonal 2 = 0.52 mm

Step 1: Calculate Average Diagonal

Average diagonal = (0.50 + 0.52) / 2
Average diagonal = 0.51 mm

Step 2: Square the Average Diagonal

d² = 0.51² = 0.2601

Step 3: Apply the Formula

HV = 1.8544 × 10 / 0.2601
HV ≈ 71.3 HV

This result suggests a relatively soft material.

Advantages of Using a Vickers Hardness Calculator

Using an online or digital calculator offers several benefits.

1. Faster Calculations

Manual calculations can take time and increase the chance of errors. A calculator produces results instantly.

2. Automatic Unit Conversion

Many tools convert between:

• Newtons
• kilogram-force
• gram-force
• micrometers
• millimeters

This saves time and prevents conversion mistakes.

3. Accurate Results

The formula is applied automatically, which reduces calculation errors.

4. Useful for Students and Engineers

The calculator is helpful for:

• Mechanical engineering students
• Metallurgy professionals
• Quality control engineers
• Manufacturing technicians

Applications of the Vickers Hardness Test

The Vickers hardness test is widely used in many industries.

Metallurgy

Engineers use it to evaluate:

• Heat-treated metals
• Alloy strength
• Surface hardness

Manufacturing

Manufacturers check hardness during:

• Quality control
• Production inspection
• Material verification

Research and Development

Researchers study:

• New alloys
• Surface coatings
• Thin materials

Microhardness Testing

The Vickers method can measure very small indentations, making it ideal for microhardness testing.

Vickers vs Other Hardness Tests

Several hardness testing methods exist. Each has its own use case.

The Vickers test stands out because it works for both soft and extremely hard materials using a single scale.

Common Mistakes When Calculating HV

To get accurate results, avoid these common errors.

Incorrect Units

Always ensure:

• Load is converted to kgf
• Diagonals are in mm

Measurement Errors

The diagonals must be measured precisely using a microscope.

Uneven Surface

A rough surface can distort the indentation and produce incorrect results.

Improper Load

Using the wrong load may produce inaccurate hardness values.

Tips for Accurate Vickers Hardness Testing

Follow these simple practices for reliable results.

• Use a clean and polished surface
• Measure diagonals carefully
• Apply the correct test load
• Take multiple measurements
• Use the average diagonal value

These steps improve accuracy and consistency.

Why Online Hardness Calculators Are Useful

Engineering calculations often involve repeated formulas. Online calculators simplify the process by providing:

• Instant results
• Built-in conversions
• Clear output values
• Material hardness interpretation

For students and professionals, this saves time and improves productivity.

Conclusion

The Vickers Hardness Number Calculator is a simple yet powerful tool used to determine the hardness of materials. By entering the applied load and the two indentation diagonals, the calculator quickly computes the Vickers hardness value (HV).

This method is widely used in metallurgy, manufacturing, and engineering because it works for both soft and hard materials while maintaining high accuracy.