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info Overview

Correct a hydrometer reading for the gap between sample and calibration temperature, showing adjusted gravity and change for values from 0.990 to 1.170.

📘 How to Use

  1. Set your measured gravity with the slider
  2. Enter the sample temperature of the liquid you measured
  3. Enter the hydrometer's calibration temperature (often 68°F / 20°C)
  4. Read the corrected gravity and the exact change

Hydrometer Temperature Correction Calculator

1.050
0.990 1.170

The value read on the hydrometer, from 0.990 to 1.170.

°C

Temperature of the liquid when measured.

°C

The hydrometer's rated temperature, often 20°C or 60°F.

thermostat Results

Corrected gravity

—

Correction amount

—

The change applied to your reading.

※ Uses the standard hydrometer correction polynomial (a water-density fit, in °F).

※ The correction is tiny near the calibration temperature and grows with the gap; treat it as a guide within roughly 0–100°C.

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Hydrometer Temperature Correction Calculator | Adjust a Reading for Sample Temperature

A hydrometer reading drifts off as the liquid's temperature moves away from the scale's calibration point. This tool takes your measured gravity, the sample temperature, and the calibration temperature, and returns the corrected gravity plus the exact amount it changed. It covers readings from 0.990 to 1.170 and works for homebrew beer, wine, mead, and cider gravity checks.

💡 About this tool

A hydrometer is etched to read accurately at one reference temperature. Most modern beer and wine hydrometers are calibrated at 68°F (20°C), while older ones often use 60°F (15.5°C). The calibration temperature is usually printed right on the scale. If you measure at exactly that temperature, no correction is needed — but a fresh, warm wort or a still-cooling sample will read off.

The direction is predictable. When the sample is warmer than the calibration temperature, the liquid is less dense and the hydrometer sinks deeper, so it reads lower than the true gravity. A cold sample reads high. For a hydrometer calibrated at 68°F reading a warmer sample, the corrected gravity comes out higher than what you saw — which is why this calculator adds (or subtracts) the right amount instead of making you read a correction chart.

🧐 Frequently asked questions

Where do I find the calibration temperature? It is printed or etched on the hydrometer scale, usually as 68°F or 60°F (20°C or 15.5°C). If it is missing, measure distilled water at a known temperature: the temperature where it reads exactly 1.000 is the calibration point.

How much error does skipping the correction cause? Near the calibration temperature the correction is tiny and a few degrees can be ignored. It grows as the gap widens — a 10°F or 20°F difference is enough to shift a gravity reading by several points, which matters for an accurate ABV estimate.

Should I correct for the hydrometer's own error too? Yes, separately. Measure distilled water at the calibration temperature; if it does not read 1.000, note that offset and apply it to every reading. This tool handles the temperature correction; keep the instrument's offset as a separate adjustment.

Do the two temperatures need the same units? Yes. The English version has an °F/°C unit toggle, and both the sample and calibration temperature use the same unit system at once.

📚 Why temperature changes the reading

Specific gravity is the density of a liquid relative to water at a reference temperature, set to 1.000. Because water itself expands and contracts with temperature, the same dissolved-sugar liquid pushes the hydrometer to a slightly different depth as it warms or cools. This tool uses the temperature-correction polynomial that brewing references widely adopt — a cubic fit to water's density curve in degrees Fahrenheit. It stays accurate across a wider span than the quick rule of thumb (a small fixed shift per degree), which is why brewing calculators favor the polynomial form.