Why are some output fields shown as N/A?

Hardness scales have different valid ranges. For example, HRB is typically used for softer materials (25–100 HRB) and does not extend into the high-hardness zone covered by HRC. When a conversion falls outside a scale's valid range, it is shown as N/A.

How accurate are these conversions?

The conversions follow the ASTM E140 standard table, which is the most widely accepted reference for hardness conversion of non-austenitic steels. Results are approximate — hardness is material-specific and exact conversion depends on alloy composition and microstructure.

What is the difference between Rockwell HRC and HRB?

HRC (C scale) uses a diamond Brale indenter with a 150 kgf load and is used for hard materials (typically above 20 HRC). HRB (B scale) uses a 1/16-inch ball indenter with 100 kgf and is suited for softer materials like aluminum and mild steel.

Can I convert hardness to tensile strength?

An approximate tensile strength in MPa can be estimated from Brinell hardness as: Tensile Strength ≈ 3.45 × HB. This tool shows this estimate alongside the hardness conversions for steel materials.

Does this tool work for all metals?

The ASTM E140 conversion table applies primarily to non-austenitic steels. Conversions for aluminum, copper, titanium, and other non-ferrous metals differ and require separate tables. Use this tool as a guide for steel alloys.

Hardness Conversion Calculator

Name: Hardness Conversion Calculator
Availability: InStock
Author: Nham Vu

Enter a hardness value in any scale and instantly convert it to Rockwell HRA, HRB, HRC, Brinell HB, Vickers HV, and Knoop HK.

Input Hardness Value

Scale

Value

Conversions follow the ASTM E140 standard table for non-austenitic steels. Results are approximate — actual values may vary by alloy composition.

Enter a value and click Convert

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Summary

Enter a hardness value in any scale and instantly convert it to Rockwell HRA, HRB, HRC, Brinell HB, Vickers HV, and Knoop HK.

How it works

Select the input hardness scale from the dropdown (HRC, HRB, HRA, HB, HV, or HK).
Enter your hardness value in the input field.
The calculator looks up the nearest match in the ASTM E140 conversion table.
All equivalent hardness values for the other scales are displayed immediately.
Copy any individual result or the full conversion summary with one click.

Use cases

Convert supplier hardness specs between Rockwell and Brinell for procurement.
Verify heat treatment results across different testing instruments.
Cross-reference Vickers microhardness readings with Rockwell HRC for engineering specs.
Translate hardness data when switching between testing standards in a lab.
Estimate tensile strength from Brinell or Vickers hardness readings.
Compare material hardness values reported in different international standards.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu