CalcDomain

homebrew abv calculator

A precise, accessibility-first tool for homebrewers to compute Alcohol by Volume (ABV) and related metrics from Original Gravity (OG) and Final Gravity (FG). Choose between Standard or Advanced methods, apply hydrometer temperature correction, and get Plato-based analytics instantly.

Results

Alcohol by Volume (ABV)
0.00%
Alcohol by Weight (ABW)
0.00%
Original Extract
0.00 °P
Final Extract (Apparent)
0.00 °P
Real Extract
0.00 °P
Apparent Attenuation
0.0%

Results update automatically as you type. Values are rounded for readability.

Data Source and Methodology

Authoritative Data Source: American Society of Brewing Chemists (ASBC), Methods of Analysis. Wort-12: Extract—Specific Gravity and Plato (2014), and Beer-4/Beer-6: Alcohol in Beer (various editions). Official resource: asbcnet.org — Methods of Analysis. Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

For enhanced ABV accuracy we implement the widely used Terrill correlation alongside the standard linear factor method. Hydrometer temperature correction follows the polynomial water density compensation commonly used in brewing software.

The Formula Explained

LaTeX notation is shown; variables are defined in the Glossary.

1) Standard ABV

ABV_{\%} = (OG - FG) \times 131.25

2) Advanced ABV (Terrill)

ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}

3) Plato (°P) from Specific Gravity

P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}

4) Real Extract (Balling)

RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}

5) Apparent Attenuation

AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100

6) Alcohol by Weight

ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG}

7) Hydrometer Temperature Correction

SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}

Glossary of Variables

Original Gravity (OG)
Specific gravity of wort before fermentation (e.g., 1.050).
Final Gravity (FG)
Specific gravity after fermentation; typically lower than OG (e.g., 1.010).
ABV (%)
Alcohol by Volume; primary strength measure for beer.
ABW (%)
Alcohol by Weight; ABV scaled by beer density.
Plato (°P)
Percentage by weight of dissolved extract (sugars) in wort/beer.
Real Extract (RE)
Extract adjusted for alcohol presence, approximating residual sugars.
Apparent Attenuation (AA%)
Degree to which fermentable extract appears to have been consumed.
Temperature Correction
Adjustment to SG readings when sample temperature differs from hydrometer calibration.

How It Works: A Step-by-Step Example

  1. Inputs: OG = 1.050, FG = 1.012, 20°C sample, 20°C calibration (no temperature bias).
  2. Convert to Plato: P_{OG} \approx 12.39\,°P,\; P_{FG} \approx 3.07\,°P
  3. Standard ABV: ABV = (1.050 - 1.012)\times 131.25 \approx 4.99\%
  4. Advanced (Terrill): ABV \approx \frac{76.08\times 0.038}{1.775 - 1.050}\times \frac{1.012}{0.794} \approx 5.08\%
  5. ABW from ABV and FG: ABW \approx \frac{0.79336\times 5.08}{1.012} \approx 3.98\%
  6. Real Extract: RE = 0.1808 \times 12.39 + 0.8192 \times 3.07 \approx 4.71\,°P
  7. Apparent Attenuation: AA = \frac{12.39 - 3.07}{12.39}\times 100 \approx 75.2\%

Frequently Asked Questions (FAQ)

Which ABV method should I choose?

The Advanced (Terrill) method is recommended for improved accuracy, especially for higher gravity beers. The Standard method is sufficient for low to moderate OG beers.

How far can the sample temperature be from calibration before I must correct?

Any difference can bias results, but corrections become important beyond ~5–6°C (10°F). Use the correction option for best accuracy.

Why do Plato values matter?

Plato expresses extract as mass percentage and underpins professional brewing calculations, enabling Real Extract and attenuation metrics.

Is ABW just ABV times a constant?

ABW is derived from ABV and the beer’s density (FG). We use ABW = 0.79336 × ABV / FG.

My FG equals OG. What does it mean?

Fermentation likely did not start or the readings are off. Recheck calibration, temperature, and measurement technique.

Can this calculator handle refractometer readings?

This tool targets hydrometer SG. For refractometers, a wort correction factor and alcohol correction are required. Use a refractometer-specific calculator.

Are the formulas peer-reviewed?

The Plato relationships trace back to Balling/Plato and are standardized in ASBC methods. The Terrill correlation is a widely accepted empirical improvement used by many brewing tools.

Strumento sviluppato da Ugo Candido,. Contenuti verificati da,.

Ultima revisione per l'accuratezza in data: .

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
LaTeX notation is shown; variables are defined in the Glossary. 1) Standard ABV ABV_{\%} = (OG - FG) \times 131.25 2) Advanced ABV (Terrill) ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794} 3) Plato (°P) from Specific Gravity P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3} 4) Real Extract (Balling) RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG} 5) Apparent Attenuation AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100 6) Alcohol by Weight ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG} 7) Hydrometer Temperature Correction SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}
Formula (extracted text)
ABV_{\%} = (OG - FG) \times 131.25
Formula (extracted text)
ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}
Formula (extracted text)
P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}
Formula (extracted text)
RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}
Formula (extracted text)
AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn
, ', svg: { fontCache: 'global' } };
CalcDomain

homebrew abv calculator

A precise, accessibility-first tool for homebrewers to compute Alcohol by Volume (ABV) and related metrics from Original Gravity (OG) and Final Gravity (FG). Choose between Standard or Advanced methods, apply hydrometer temperature correction, and get Plato-based analytics instantly.

Results

Alcohol by Volume (ABV)
0.00%
Alcohol by Weight (ABW)
0.00%
Original Extract
0.00 °P
Final Extract (Apparent)
0.00 °P
Real Extract
0.00 °P
Apparent Attenuation
0.0%

Results update automatically as you type. Values are rounded for readability.

Data Source and Methodology

Authoritative Data Source: American Society of Brewing Chemists (ASBC), Methods of Analysis. Wort-12: Extract—Specific Gravity and Plato (2014), and Beer-4/Beer-6: Alcohol in Beer (various editions). Official resource: asbcnet.org — Methods of Analysis. Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

For enhanced ABV accuracy we implement the widely used Terrill correlation alongside the standard linear factor method. Hydrometer temperature correction follows the polynomial water density compensation commonly used in brewing software.

The Formula Explained

LaTeX notation is shown; variables are defined in the Glossary.

1) Standard ABV

ABV_{\%} = (OG - FG) \times 131.25

2) Advanced ABV (Terrill)

ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}

3) Plato (°P) from Specific Gravity

P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}

4) Real Extract (Balling)

RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}

5) Apparent Attenuation

AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100

6) Alcohol by Weight

ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG}

7) Hydrometer Temperature Correction

SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}

Glossary of Variables

Original Gravity (OG)
Specific gravity of wort before fermentation (e.g., 1.050).
Final Gravity (FG)
Specific gravity after fermentation; typically lower than OG (e.g., 1.010).
ABV (%)
Alcohol by Volume; primary strength measure for beer.
ABW (%)
Alcohol by Weight; ABV scaled by beer density.
Plato (°P)
Percentage by weight of dissolved extract (sugars) in wort/beer.
Real Extract (RE)
Extract adjusted for alcohol presence, approximating residual sugars.
Apparent Attenuation (AA%)
Degree to which fermentable extract appears to have been consumed.
Temperature Correction
Adjustment to SG readings when sample temperature differs from hydrometer calibration.

How It Works: A Step-by-Step Example

  1. Inputs: OG = 1.050, FG = 1.012, 20°C sample, 20°C calibration (no temperature bias).
  2. Convert to Plato: P_{OG} \approx 12.39\,°P,\; P_{FG} \approx 3.07\,°P
  3. Standard ABV: ABV = (1.050 - 1.012)\times 131.25 \approx 4.99\%
  4. Advanced (Terrill): ABV \approx \frac{76.08\times 0.038}{1.775 - 1.050}\times \frac{1.012}{0.794} \approx 5.08\%
  5. ABW from ABV and FG: ABW \approx \frac{0.79336\times 5.08}{1.012} \approx 3.98\%
  6. Real Extract: RE = 0.1808 \times 12.39 + 0.8192 \times 3.07 \approx 4.71\,°P
  7. Apparent Attenuation: AA = \frac{12.39 - 3.07}{12.39}\times 100 \approx 75.2\%

Frequently Asked Questions (FAQ)

Which ABV method should I choose?

The Advanced (Terrill) method is recommended for improved accuracy, especially for higher gravity beers. The Standard method is sufficient for low to moderate OG beers.

How far can the sample temperature be from calibration before I must correct?

Any difference can bias results, but corrections become important beyond ~5–6°C (10°F). Use the correction option for best accuracy.

Why do Plato values matter?

Plato expresses extract as mass percentage and underpins professional brewing calculations, enabling Real Extract and attenuation metrics.

Is ABW just ABV times a constant?

ABW is derived from ABV and the beer’s density (FG). We use ABW = 0.79336 × ABV / FG.

My FG equals OG. What does it mean?

Fermentation likely did not start or the readings are off. Recheck calibration, temperature, and measurement technique.

Can this calculator handle refractometer readings?

This tool targets hydrometer SG. For refractometers, a wort correction factor and alcohol correction are required. Use a refractometer-specific calculator.

Are the formulas peer-reviewed?

The Plato relationships trace back to Balling/Plato and are standardized in ASBC methods. The Terrill correlation is a widely accepted empirical improvement used by many brewing tools.

Strumento sviluppato da Ugo Candido,. Contenuti verificati da,.

Ultima revisione per l'accuratezza in data: .

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
LaTeX notation is shown; variables are defined in the Glossary. 1) Standard ABV ABV_{\%} = (OG - FG) \times 131.25 2) Advanced ABV (Terrill) ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794} 3) Plato (°P) from Specific Gravity P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3} 4) Real Extract (Balling) RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG} 5) Apparent Attenuation AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100 6) Alcohol by Weight ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG} 7) Hydrometer Temperature Correction SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}
Formula (extracted text)
ABV_{\%} = (OG - FG) \times 131.25
Formula (extracted text)
ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}
Formula (extracted text)
P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}
Formula (extracted text)
RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}
Formula (extracted text)
AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn
]], displayMath: [['\\[','\\]']] }, svg: { fontCache: 'global' } };, svg: { fontCache: 'global' } };
CalcDomain

homebrew abv calculator

A precise, accessibility-first tool for homebrewers to compute Alcohol by Volume (ABV) and related metrics from Original Gravity (OG) and Final Gravity (FG). Choose between Standard or Advanced methods, apply hydrometer temperature correction, and get Plato-based analytics instantly.

Results

Alcohol by Volume (ABV)
0.00%
Alcohol by Weight (ABW)
0.00%
Original Extract
0.00 °P
Final Extract (Apparent)
0.00 °P
Real Extract
0.00 °P
Apparent Attenuation
0.0%

Results update automatically as you type. Values are rounded for readability.

Data Source and Methodology

Authoritative Data Source: American Society of Brewing Chemists (ASBC), Methods of Analysis. Wort-12: Extract—Specific Gravity and Plato (2014), and Beer-4/Beer-6: Alcohol in Beer (various editions). Official resource: asbcnet.org — Methods of Analysis. Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

For enhanced ABV accuracy we implement the widely used Terrill correlation alongside the standard linear factor method. Hydrometer temperature correction follows the polynomial water density compensation commonly used in brewing software.

The Formula Explained

LaTeX notation is shown; variables are defined in the Glossary.

1) Standard ABV

ABV_{\%} = (OG - FG) \times 131.25

2) Advanced ABV (Terrill)

ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}

3) Plato (°P) from Specific Gravity

P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}

4) Real Extract (Balling)

RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}

5) Apparent Attenuation

AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100

6) Alcohol by Weight

ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG}

7) Hydrometer Temperature Correction

SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}

Glossary of Variables

Original Gravity (OG)
Specific gravity of wort before fermentation (e.g., 1.050).
Final Gravity (FG)
Specific gravity after fermentation; typically lower than OG (e.g., 1.010).
ABV (%)
Alcohol by Volume; primary strength measure for beer.
ABW (%)
Alcohol by Weight; ABV scaled by beer density.
Plato (°P)
Percentage by weight of dissolved extract (sugars) in wort/beer.
Real Extract (RE)
Extract adjusted for alcohol presence, approximating residual sugars.
Apparent Attenuation (AA%)
Degree to which fermentable extract appears to have been consumed.
Temperature Correction
Adjustment to SG readings when sample temperature differs from hydrometer calibration.

How It Works: A Step-by-Step Example

  1. Inputs: OG = 1.050, FG = 1.012, 20°C sample, 20°C calibration (no temperature bias).
  2. Convert to Plato: P_{OG} \approx 12.39\,°P,\; P_{FG} \approx 3.07\,°P
  3. Standard ABV: ABV = (1.050 - 1.012)\times 131.25 \approx 4.99\%
  4. Advanced (Terrill): ABV \approx \frac{76.08\times 0.038}{1.775 - 1.050}\times \frac{1.012}{0.794} \approx 5.08\%
  5. ABW from ABV and FG: ABW \approx \frac{0.79336\times 5.08}{1.012} \approx 3.98\%
  6. Real Extract: RE = 0.1808 \times 12.39 + 0.8192 \times 3.07 \approx 4.71\,°P
  7. Apparent Attenuation: AA = \frac{12.39 - 3.07}{12.39}\times 100 \approx 75.2\%

Frequently Asked Questions (FAQ)

Which ABV method should I choose?

The Advanced (Terrill) method is recommended for improved accuracy, especially for higher gravity beers. The Standard method is sufficient for low to moderate OG beers.

How far can the sample temperature be from calibration before I must correct?

Any difference can bias results, but corrections become important beyond ~5–6°C (10°F). Use the correction option for best accuracy.

Why do Plato values matter?

Plato expresses extract as mass percentage and underpins professional brewing calculations, enabling Real Extract and attenuation metrics.

Is ABW just ABV times a constant?

ABW is derived from ABV and the beer’s density (FG). We use ABW = 0.79336 × ABV / FG.

My FG equals OG. What does it mean?

Fermentation likely did not start or the readings are off. Recheck calibration, temperature, and measurement technique.

Can this calculator handle refractometer readings?

This tool targets hydrometer SG. For refractometers, a wort correction factor and alcohol correction are required. Use a refractometer-specific calculator.

Are the formulas peer-reviewed?

The Plato relationships trace back to Balling/Plato and are standardized in ASBC methods. The Terrill correlation is a widely accepted empirical improvement used by many brewing tools.

Strumento sviluppato da Ugo Candido,. Contenuti verificati da,.

Ultima revisione per l'accuratezza in data: .

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted text)
LaTeX notation is shown; variables are defined in the Glossary. 1) Standard ABV ABV_{\%} = (OG - FG) \times 131.25 2) Advanced ABV (Terrill) ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794} 3) Plato (°P) from Specific Gravity P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3} 4) Real Extract (Balling) RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG} 5) Apparent Attenuation AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100 6) Alcohol by Weight ABW_{\%} = \frac{0.79336 \times ABV_{\%}}{FG} 7) Hydrometer Temperature Correction SG_{corr} = SG_{obs} \times \frac{CF(T_{sample})}{CF(T_{cal})} CF(T) = 1.00130346 - 1.34722124\times10^{-4}T + 2.04052596\times10^{-6}T^{2} - 2.32820948\times10^{-9}T^{3}
Formula (extracted text)
ABV_{\%} = (OG - FG) \times 131.25
Formula (extracted text)
ABV_{\%} = \frac{76.08 \times (OG - FG)}{1.775 - OG} \times \frac{FG}{0.794}
Formula (extracted text)
P = -616.868 + 1111.14\,SG - 630.272\,SG^{2} + 135.997\,SG^{3}
Formula (extracted text)
RE = 0.1808 \times P_{OG} + 0.8192 \times P_{FG}
Formula (extracted text)
AA_{\%} = \frac{P_{OG} - P_{FG}}{P_{OG}} \times 100
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn