Saponification Value Calculator

Calculate the saponification value of fats and oils from titration data.

Supports 21 volume units, 3 molarity units, and 7 mass units.

Updated September 7, 2026

CreatorFrank Zhao

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What is saponification value?

The saponification value (SV) is a key analytical parameter used in fats and oils chemistry. It measures the number of milligrams of potassium hydroxide (KOH) required to completely saponify — that is, to convert to soap — one gram of a fat or oil under defined conditions.

In practical terms, a higher SV indicates shorter-chain fatty acids (more KOH needed per gram), while a lower SV indicates longer-chain fatty acids (less KOH needed per gram).

SV is widely used in the soap industry for quality control, in food science for fat characterization, and in oleochemistry for determining the average molecular weight of fatty acids in a sample.

Lab Analysis

HCl back-titration

Soap Making

Quality assessment

Bidirectional

Solve any variable

How to use this calculator

The calculator connects five quantities: blank titre volume, sample titre volume, HCl molarity, weight of fat/oil, and the saponification value. Enter any four known values and the fifth is computed automatically.

Enter the blank titre (B)

The volume of standard HCl solution used to neutralize KOH in the blank titration (no fat/oil sample). This is always larger than the sample titre because no KOH is consumed by saponification.

Enter the sample titre (S)

The volume of HCl used to neutralize the remaining KOH after saponification of the fat/oil sample. Must be smaller than the blank titre for a valid result.

Enter molarity, weight, and read SV

Provide the HCl molarity (mol/L) and the weight of fat/oil sample (g). The saponification value in mg KOH/g appears instantly. You can also enter a known SV to back-calculate any of the other four parameters.

Worked example — determining SV from titration data

You perform a standard KOH back-titration with these results:

Blank titre: B = 23 mL
Sample titre: S = 2 mL
HCl molarity: M = 3 mol/L
Fat weight: W = 2 g

SV

=

\frac{(B - S) \times M \times 56.1}{W}

=

\frac{(23 - 2) \times 3 \times 56.1}{2}

= 1{,}767.15\ \text{mg KOH/g}

This very high SV suggests the sample contains short-chain fatty acids (such as coconut oil or palm kernel oil), which require more KOH per gram to saponify.

Reverse example — finding sample weight from a known SV

A quality lab knows olive oil typically has SV around 190 mg/g. They titrate: B = 3.7 mL, S = 2.1 mL, M = 0.7 mol/L. What weight of oil gives this SV?

W

=

\frac{(B - S) \times M \times 56.1}{SV}

=

\frac{(3.7 - 2.1) \times 0.7 \times 56.1}{190}

\approx 0.331\ \text{g}

This reverse calculation is useful when you need to verify sample preparation for a known oil type.

Formula and variables

Main formula

SV = \frac{(B - S) \times M \times 56.1}{W}

Symbol	Meaning	Default Unit
SV	Saponification value	mg KOH / g
B	Blank titre — HCl volume for blank	mL
S	Sample titre — HCl volume for sample	mL
M	Molarity of HCl titrant	mol / L
W	Weight of fat/oil sample	g
56.1	Molecular weight of KOH	g / mol

The constant $56.1 \text{ g/mol}$ is the molar mass of potassium hydroxide (KOH). It converts the molar quantity of KOH consumed during saponification into the milligram-equivalent that defines SV.

Validation rule: The blank titre (B) must always be larger than the sample titre (S), because saponification consumes KOH. If B ≤ S, the result would be zero or negative — this is physically meaningless and the calculator flags it as an error.

Reverse solve modes

This calculator is fully bidirectional. Besides computing SV from titration data, you can input SV and any three other parameters to find the missing one:

Find sample titre

S = B - \frac{SV \times W}{M \times 56.1}

Find blank titre

B = S + \frac{SV \times W}{M \times 56.1}

Find molarity

M = \frac{SV \times W}{(B - S) \times 56.1}

Find sample weight

W = \frac{(B - S) \times M \times 56.1}{SV}

Common oils and SV values

Different fats and oils have characteristic saponification values that reflect their fatty acid chain lengths. The table below shows typical ranges you can use as a sanity check.

Fat / Oil	SV Range (mg/g)	Key Fatty Acids
Coconut oil	250 – 270	Lauric (C12), Myristic (C14)
Palm kernel oil	230 – 250	Lauric (C12), Palmitic (C16)
Butter fat	210 – 230	Butyric (C4), Palmitic (C16)
Palm oil	195 – 205	Palmitic (C16), Oleic (C18:1)
Olive oil	185 – 196	Oleic (C18:1)
Soybean oil	188 – 195	Linoleic (C18:2), Oleic (C18:1)
Sunflower oil	185 – 194	Linoleic (C18:2), Oleic (C18:1)
Rapeseed (Canola)	170 – 180	Oleic (C18:1), Erucic (C22:1)
Castor oil	176 – 182	Ricinoleic (C18:1-OH)
Tung oil	185 – 195	Eleostearic (C18:3)
Linseed oil	175 – 190	Linolenic (C18:3)

Values from AOCS Official Methods and published literature. Actual SV varies with crop origin, refining, and blending.

Tips and best practices

Always run a blank

The blank titration (no fat sample) accounts for all KOH in the flask. Skipping it makes the SV result meaningless. The blank titre is always the larger of the two volumes.

Use accurate weight

Weigh the fat/oil sample to at least 0.001 g precision. A balance error of just 0.01 g in a 2 g sample introduces 0.5% error in SV — noticeable in quality control.

Use known molarity

The HCl titrant must be standardized (e.g., against sodium carbonate or borax). An inaccurate molarity propagates linearly into the SV result.

Match units carefully

The calculator supports 21 volume units, 6 molarity denominator units, and 7 mass units. Ensure each field's unit matches what you actually measured — the system auto-converts for you.

Frequently asked questions

Why is 56.1 used instead of a rounded 56?

The precise molar mass of KOH is 56.1056 g/mol. The value 56.1 is the accepted rounded constant used in AOCS and ISO standard methods for saponification value determination. Using 56.1 ensures consistency with published literature and regulatory standards.

What does a negative SV result mean?

A negative SV means the sample titre (S) is larger than the blank titre (B), which is physically impossible for a valid titration. This usually indicates a measurement error — check that you swapped the blank and sample flasks, or that contamination occurred.

Can I use NaOH instead of KOH?

SV is defined specifically in terms of KOH. If you perform the saponification with NaOH, you would be measuring a different parameter (sometimes called the "NaOH saponification value"). The standard SV with KOH is the universally accepted metric.

How does molecular weight relate to SV?

The average molecular weight of fatty acids in a fat is inversely proportional to SV: Average MW = (3 × 56,100) / SV. A higher SV means shorter average chain length and lower molecular weight.

Limitations

Assumes complete saponification: The formula requires that all KOH reacts completely with the fat sample. Incomplete saponification (e.g., insufficient reflux time) gives an artificially low SV.
Pure fats only: SV is meaningful for pure triglycerides. Samples containing free fatty acids, moisture, or unsaponifiable matter (waxes, sterols) will not give accurate results without correction.
KOH constant is fixed: The calculator uses the standard constant 56.1 g/mol for KOH molecular weight. This is appropriate for analytical-grade KOH but minor variations exist in literature.
Temperature sensitivity: Titration volumes are temperature-dependent. Perform all titrations at a consistent temperature (typically 20–25 °C) for reliable SV.
Not a purity test: SV characterizes fatty acid chain length, not purity. Two oils with the same SV can have very different fatty acid profiles.

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