IBU Calculator (Estimate)

Estimate the bitterness (IBU) of a beer from its hop bill using the Tinseth, Rager, or Garetz convention. A recipe estimate, not an official measurement — see the disclaimer below.

Calculator

Non-regulatory estimate

Add each hop, then enter your batch volume and boil gravity to estimate total bitterness (IBU).

⚠️ This is a recipe ESTIMATE, not a measurement. IBU prediction has no official government formula — a real IBU is a spectrophotometric lab result. Never use this for a tax or label filing.

Convention

TinsethThe modern homebrew default (derived from whole-hop data). A good all-round estimate — start here and stay consistent.RagerReads HIGHER than Tinseth, especially for late additions; often preferred for pellet hops. Use it if your system consistently comes out more bitter than Tinseth predicts.GaretzReads LOWER than Rager (and usually Tinseth) — a conservative low-end estimate. Simplified here: it applies Garetz’s gravity/concentration adjustment but OMITS his elevation/yeast/filtration correction factors (which this tool does not collect), so it does not reproduce full canonical Garetz.

Hop mass unit

Hop additions

Hop mass

Alpha acid %

Boil time (min)

Batch volume

Unit

Boil gravity

Defaults to 1.050 if left blank.

Enter at least one hop addition (mass, alpha acid, and boil time) plus a batch volume to see the estimate.

Estimate only — a homebrewing convention (Tinseth / Rager / Garetz), not an official measurement. A real IBU is an ASBC spectrophotometric lab result.

Reference tools, not a system of record. These free calculators are provided for convenience and general reference only. They are not a system of record and must not be used as the basis for any TTB or state compliance filing — even when a result is correct. Your official filings are governed by the applicable measurement and gauging methods and by your own production records.