Dilution & Blending Calculator

How this works

Both dilution and blending are worked in "gravity points" — (SG - 1) x 1000 — because gravity points are additive across volumes in a way specific gravity itself is not. A litre of 1.080 wort mixed with a litre of 1.000 water doesn't average to 1.040 by coincidence; it works because 80 gravity points spread across double the volume becomes 40 points per litre, and that additive relationship is what both calculations here are built on.

Dilution solves for how much water to add to bring an over-strength batch down to a target gravity, using the fact that total gravity points stay constant: finalVolume = currentVolume x currentPoints / targetPoints. This is common after a stuck sparge ran higher than planned, or a deliberate high-gravity brew day meant to be diluted down at packaging.

Blending solves a different problem: given a batch at one gravity and a second batch at a different gravity, how much of the second do you need to add to the first to land on a target gravity in between the two? The tool solves this directly from the same additive-points relationship, rather than requiring you to guess-and-check a ratio.

Why not just use dilution for everything?

Dilution can only ever lower gravity — you're adding water, which has zero gravity points, so the blended result is always somewhere between the original gravity and 1.000. If your target gravity is higher than your current batch, dilution can't get you there; you need something stronger to blend in instead, which is exactly the blending mode of this tool.

Reading the result

Both dilution and blending assume the two liquids mix cleanly and gravity behaves additively, which is a very good approximation for wort, beer, cider and mead at normal brewing strengths. It doesn't account for flavour dilution, though — halving your gravity with water also roughly halves everything else dissolved in that liquid (hop bitterness, malt character, colour), which is worth thinking through before diluting a beer you were otherwise happy with just to hit a gravity target.

If you're blending two already-fermented batches rather than two worts, remember that ABV doesn't blend in quite the same simple additive way gravity points do — check the resulting ABV with the ABV calculator once you know your final blended gravity and account for the alcohol each batch is contributing.

A worked example

A batch that came in at 1.065 instead of the intended 1.050 on a 19 L (5 gallon) run needs 5.7 L of water added to bring it down to the target 1.050 — the calculator conserves total gravity points exactly, so the diluted batch ends up at 24.7 L total rather than staying at 19 L. For blending, imagine a 10 L batch at 1.080 and a second batch at 1.030 available to blend in: hitting a 1.060 target needs roughly 6.7 L of the weaker batch, landing at just under 17 L total once combined.

When gravity alone isn't the whole story

Both modes assume the two liquids you're combining mix cleanly and that gravity is the only thing you care about matching. In practice, diluting also thins hop bitterness, malt character and colour roughly in proportion, and blending combines whatever flavour profile each batch already has — a blend that hits the right gravity can still taste like two different beers awkwardly mixed together if the two batches were built around very different hop or malt characters to begin with.