--- title: "Hardness Converter — HB, HV, HRC, HRB" description: "Convert HB, HV, HRC and HRB ✅ published ASTM E140 / ISO 18265 tables ⭐ values outside the standard's range are refused, never extrapolated." canonical: https://steelequivalents.com/calculators/hardness-converter language: en robots: index, follow og_type: website type: calculator-hardness-converter language_alternates: en: https://steelequivalents.com/calculators/hardness-converter.md cs: https://steelequivalents.com/cs/kalkulačky/převodník-tvrdosti.md de: https://steelequivalents.com/de/rechner/härte-umrechner.md es: https://steelequivalents.com/es/calculadoras/conversor-de-dureza.md fr: https://steelequivalents.com/fr/calculateurs/convertisseur-de-dureté.md hu: https://steelequivalents.com/hu/kalkulátorok/keménységátszámító.md it: https://steelequivalents.com/it/calcolatori/convertitore-di-durezza.md nl: https://steelequivalents.com/nl/calculators/hardheid-omrekenen.md pl: https://steelequivalents.com/pl/kalkulatory/przelicznik-twardości.md pt: https://steelequivalents.com/pt/calculadoras/conversor-de-dureza.md ru: https://steelequivalents.com/ru/калькуляторы/конвертер-твёрдости.md tr: https://steelequivalents.com/tr/hesaplayıcılar/sertlik-dönüştürücü.md zh: https://steelequivalents.com/zh/计算器/硬度换算.md ja: https://steelequivalents.com/ja/計算ツール/硬さ換算.md ar: https://steelequivalents.com/ar/حاسبات/محول-الصلادة.md ko: https://steelequivalents.com/ko/계산기/경도-환산.md pt-br: https://steelequivalents.com/pt-br/calculadoras/conversor-de-dureza.md hi: https://steelequivalents.com/hi/कैलकुलेटर/कठोरता-परिवर्तक.md content_hash: sha256:5ef55fe504dcc28b0d5b45ba8371c9443fe66d5d888f4baf22990212cca37891 generated: 2026-09-24 --- > **Machine-readable Markdown rendering.** This is a Markdown representation of a web page, > served for AI agents and crawlers as a token-efficient alternative to the full HTML. > Full interactive HTML version: https://steelequivalents.com/calculators/hardness-converter > Canonical URL: https://steelequivalents.com/calculators/hardness-converter > Available languages: en, cs, de, es, fr, hu, it, nl, pl, pt, ru, tr, zh, ja, ar, ko, pt-br, hi > Change detection: `content_hash` is the SHA-256 of this document's Markdown body — everything > below this block, whitespace-trimmed, excluding the front-matter. Compare it to detect a real > content change; `generated` moves on every render and is not a change signal. ![Hardness Converter — HB, HV, HRC, HRB](/images/uploads/d56ca3d0-194e-429f-b189-5c911d8d79b2/hardness-converter-calculator-diamond-indenter-polished-mount-1920x1080.jpg) Conversion # Hardness Converter There is no universal hardness formula. Conversions are empirical, published as tables, and valid only for the material class they were measured on — so pick the class first. This calculator returns the nearest published row of ASTM E140 / ISO 18265, refuses values outside it, and leaves a cell empty where the standard prints none. A real GET form: computes correctly with JavaScript off. Material Material class Non-austenitic steel — carbon and low-alloyAustenitic stainless steel — sheetAustenitic stainless steel — annealed plate Carbon and low-alloy steel. For 304, 316, 321 and their relatives switch to an austenitic class — they sit on a different curve entirely. Measured hardness Scale you measured on HRC (Rockwell C)HB (Brinell)HV (Vickers)HRB (Rockwell B) Hardness value This table covers HRC (Rockwell C) from 20 to 68. Outside that span the conversion was never measured, so it is refused rather than extrapolated. Calculate [Reset](/calculators/hardness-converter.md "Reset the calculator to its default values") Recalculates on submit — the same value renders with JavaScript off. ### Result Valid range HV**458** HB**432** HRC**46** HRB**—** You entered 45. The nearest published row is 46 HRC (Rockwell C) — the standard prints no row at your exact value, and interpolating between rows is not a conversion. Estimated tensile strength 1580 MPa (229.2 ksi) — a correlation with roughly ±15 % scatter, never a substitute for a tensile test. ASTM E140 Table 1 / ISO 18265 Annex A — non-austenitic steel **Download as PDF** Result sheet · A4 Run a calculation first — then the sheet is ready to download. Calculated on SteelEquivalents.com — send us the figures for a quotation. The update failed. Your entries have been kept — please try again. ## Why one hardness table is not enough Each hardness test measures something slightly different. Rockwell C presses a diamond cone and reads a depth; Brinell presses a ball and measures the width of the dent; Vickers presses a pyramid and measures its diagonal. Relating them means measuring the same specimens on several machines and fitting a curve — and that curve depends on how the material deforms. Austenitic stainless work-hardens heavily under the indenter, so it sits on a different curve from carbon and low-alloy steel; applying the carbon-steel table to a 304 sheet is the most common hardness-conversion error there is. ASTM E140 therefore publishes separate tables per class, and the tensile-strength column of the non-austenitic table is explicitly an approximation, not a substitute for a tensile test. ## Hardness conversion — frequently asked What is 45 HRC in Brinell? For carbon and low-alloy steel, the ASTM E140 table prints rows at 44 HRC (409 HB, 434 HV) and 46 HRC (432 HB, 458 HV) but none at 45. This calculator returns the nearest published row and says which one it used, rather than interpolating a value the standard never measured. For austenitic stainless the answer is different again — switch the material class. Why is there no HRC value below 20? On soft material the Rockwell C diamond barely penetrates, so the reading loses resolution and repeatability. ASTM E140 stops printing HRC below 20 for that reason, and the correct scale in that range is Rockwell B. This calculator leaves the cell empty there rather than showing a number the standard declines to publish. Can I use a hardness test instead of a tensile test? Not for a certificate. The tensile column here is a correlation with roughly ±15 % scatter, useful for a quick sanity check on incoming material or a heat treatment, and for nothing that has to be signed. Where a specification calls for a tensile value, it means a tensile test on a specimen — a hardness reading cannot replace it, and no standard treats it as equivalent. Why does 304 stainless need a different table? Because austenitic grades work-harden strongly. Under the indenter the surface hardens as it deforms, so the relationship between the scales differs from carbon steel — and it differs again between thin sheet and annealed plate, which is why ASTM E140 publishes those as two separate tables. Reading a 304 sheet against the carbon-steel table gives a number that looks reasonable and is simply wrong.