Final Gravity Calculator

Enter your original gravity and current gravity to calculate apparent attenuation, remaining extract, and whether fermentation is complete.

Gravity Readings

Measured before pitching yeast (typical range: 1.030–1.100)

Measured after fermentation slows (typical range: 1.005–1.020)

From your yeast strain data sheet — used for fermentation status check

Enter gravity readings and click Calculate

Summary

Enter your original gravity and current gravity to calculate apparent attenuation, remaining extract, and whether fermentation is complete.

How it works

  1. Measure and enter your original gravity (OG) taken before pitching yeast.
  2. Measure and enter your current or final gravity (FG) using a hydrometer or refractometer.
  3. The calculator computes apparent attenuation as a percentage of fermentable sugars consumed.
  4. Real attenuation is derived by applying a correction factor for alcohol masking.
  5. Compare your attenuation against your yeast strain's expected range to judge fermentation completeness.

Use cases

  • Verify that fermentation has reached its expected final gravity before packaging.
  • Diagnose stuck fermentation by comparing actual vs. expected attenuation.
  • Calculate the dryness or residual sweetness of your finished beer.
  • Track fermentation progress across multiple gravity readings.
  • Compare yeast strains by their real-world attenuation performance.
  • Estimate remaining fermentable extract to decide whether to add adjuncts.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu