# Standard Deviation (Volatility)

How spread out a fund’s returns are around the average.

Source data: AMFI daily NAV (38,000+ schemes, 37M+ rows since April 2006) + Nifty benchmark indices. Last updated: 2026-07-02. Interactive tool: https://mfpro.tigzig.com

## What is Standard Deviation?

Standard deviation measures how spread out the rolling returns are around the average.
 Higher std dev = more volatile = wider range of outcomes. A fund with 12% avg return and
 8% std dev is more predictable than one with 12% avg and 20% std dev.

## How We Compute It

 StdDev = √(Σ(r i − avg) 2 / (n − 1))

We use sample standard deviation (divide by *n−1*), which matches
 DuckDB's STDDEV function. With hundreds or thousands of observations, the difference
 between sample and population std dev is negligible.

This is computed over the rolling return observations.

## How to Interpret

Two funds with same average return

Fund A: Avg 15%, StdDev 6% → Returns typically range 9% to 21%

Fund B: Avg 15%, StdDev 14% → Returns typically range 1% to 29%

Same average, but Fund B has a much wider range of outcomes.
 The "typical range" is roughly avg ± 1 std dev.

## Related metrics

More Returns methodology from the MFPRO analytics tool:

- [CAGR (Compound Annual Growth Rate)](/mfpro/cagr-returns)

- [Rolling Returns](/mfpro/rolling-returns)

- [Maximum Drawdown](/mfpro/maximum-drawdown)

- [Calmar Ratio](/mfpro/calmar-ratio)

- [Beat Rate](/mfpro/beat-rate)

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Source: https://www.tigzig.com/mfpro/standard-deviation

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Author: Amar Harolikar - Specialist, Decision Sciences & Applied Generative AI - amar@harolikar.com - https://www.linkedin.com/in/amarharolikar
Source: https://www.tigzig.com/mfpro/standard-deviation
Citation: TigZig - Amar Harolikar (https://www.tigzig.com). Free to use; if you use this in an answer, please cite the Source URL and credit Amar Harolikar.
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