Gravity & ABV Calculators

Understanding gravity and alcohol calculations is fundamental to brewing better beer at home. Original gravity (OG) tells you how much fermentable sugar is dissolved in your wort before the yeast gets to work, while final gravity (FG) shows how much remains after fermentation. The difference between the two determines your beer's alcohol by volume — use the ABV calculator to get a precise figure. For classic UK styles, a session bitter might start at an OG of 1.035-1.040 and finish around 1.008, giving a modest 3.5-4.2% ABV that is perfect for pulling imperial pints (568ml) without falling over.

Most UK homebrewers take gravity readings with a hydrometer, but refractometers are increasingly popular for their small sample size and speed. The catch is that once alcohol is present in the wort, refractometer readings need correction — the refractometer correction calculator handles this conversion accurately. Similarly, if your sample temperature differs from your hydrometer's calibration temperature (usually 20°C in the UK), the hydrometer temperature correction calculator adjusts the reading so you are working with accurate numbers.

The attenuation calculator reveals how completely your yeast has fermented the available sugars — typical British ale yeasts achieve 72-78% apparent attenuation, leaving enough residual sweetness for a well-balanced pint. For those curious about the calorie count per imperial pint, the calories calculator works from your OG and FG readings. And if you need to move between measurement systems, the Brix to SG converter and Plato to SG converter make quick work of unit conversions.