SMV Calculator

Calculate Sake Meter Value (nihonshu-do) from specific gravity and interpret the result on the sweetness-to-dryness scale. Enter a specific gravity reading or a direct SMV value to see where the sake falls on the spectrum from very sweet (-15) to very dry (+15). Optionally add acidity (san-do) to compute the sweetness index for a more complete taste prediction. Includes preset values for common styles like Junmai Daiginjo, Nigori, and Dry Junmai.

Calculator

الأداة

Presets

Typical range: 0.990 -- 1.040

Range: -30 to +30

Typical range: 0.8 -- 2.5

How to Use

  1. 1
    Enter gravity or SMV

    Enter a specific gravity reading (e.g. 1.005) or type an SMV value directly into the input field.

  2. 2
    Add acidity (optional)

    Optionally enter the acidity (san-do) value to calculate the sweetness index ratio and refine the taste prediction.

  3. 3
    Read the result

    Read the result: the large SMV number, the sweetness/dryness badge, the position on the interpretation scale, and the serving temperature recommendation.

About

The Sake Meter Value, known in Japanese as nihonshu-do (日本酒度), was standardised by Japan’s National Tax Agency (Kokuzeicho) during the post-war period as an objective way to classify sake sweetness and dryness. Before its introduction, tasting panels described sake flavour in purely subjective terms, making it difficult to compare products across breweries and regions. The scale is centred on zero — the density of pure water at 15°C — and measures how much lighter or heavier a sake is after fermentation.

During brewing, Aspergillus oryzae (koji mould) converts rice starch into glucose, and yeast then ferments the glucose into alcohol. Because alcohol is lighter than water and sugar is heavier, the final density reflects the balance between residual sugar and alcohol content. A fully fermented sake with very little residual sugar will be lighter than water, giving a positive SMV (dry). A sake that retains more sugar — stopped early, fortified, or deliberately sweet — will be denser, giving a negative SMV (sweet).

In practice most commercial sake ranges from about -3 (slightly sweet) to +8 (notably dry), though extreme styles exist at -15 (dessert sake) and beyond +15 (super-dry). Since the 1980s Japanese consumers have generally preferred drier styles, pushing the average SMV upward, but craft brewers in recent years have revived sweeter, richer expressions. It is important to remember that SMV alone does not fully determine perceived taste: acidity (san-do) and amino acid content (amino-sando) modulate sweetness on the palate. A sake with SMV +3 and high acidity may taste drier than one at +6 with low acidity. For this reason, the sweetness index (san-do ÷ nihonshu-do) is sometimes used alongside SMV to give a more nuanced prediction.

FAQ

What is Sake Meter Value (SMV)?
Sake Meter Value, called nihonshu-do in Japanese, measures the density of sake relative to water at 15°C. A positive value means the sake is less dense than water (drier) because more sugar has been converted to alcohol. A negative value means the sake is denser than water (sweeter) due to residual sugar. Most sake falls between -5 and +10.
What do positive and negative SMV numbers mean?
Positive SMV indicates a drier sake with less residual sugar. Negative SMV indicates a sweeter sake with more residual sugar. Zero is the neutral point where the sake has the same density as water. A sake at +6 is noticeably dry, while -8 is quite sweet. However, perceived sweetness also depends on acidity and amino acid content.
How does acidity affect the perceived sweetness of sake?
Higher acidity makes a sake taste drier and crisper even when the SMV is low or negative. This is why two sake with the same SMV can taste very different. The sweetness index (acidity ÷ SMV) gives a more accurate taste prediction than SMV alone. A high-acidity, low-SMV sake may taste balanced rather than sweet.
Why does the same SMV taste different across two sake?
SMV measures density, not flavour perception. Amino acid content (amino-sando), acidity (san-do), serving temperature, and the specific sugars and acids present all affect how sweet or dry a sake tastes on the palate. A Junmai with SMV +3 and high amino acids may taste rounder and sweeter than a Honjozo at the same +3 with low amino acids.
How is specific gravity measured for sake?
Brewers use a special hydrometer called a nihonshu-do-kei, calibrated at 15°C. The instrument floats in the sake and reads the density directly as an SMV number. For homebrewers, a standard hydrometer gives the specific gravity (e.g. 1.005), which can be converted to SMV with the formula: SMV = ((1 / SG) - 1) × 1443.