BETA.INV Function (LibreOffice Calc)

Statistical Advanced LibreOffice Calc Introduced in LibreOffice 4.0
statistics probability beta-distribution quantile bayesian modeling

The BETA.INV function returns the inverse of the cumulative beta distribution (quantile function). It is used in Bayesian inference, A/B testing, reliability modeling, and determining percentiles of bounded probability distributions.

Compatibility

What the BETA.INV Function Does

  • Computes the quantile of the beta distribution
  • Solves for x such that CDF(x) = probability
  • Supports optional lower/upper bounds
  • Used in Bayesian credible intervals, A/B testing, and reliability

Syntax

Standard form (0 to 1)

BETA.INV(probability; alpha; beta)

Bounded form (a to b)

BETA.INV(probability; alpha; beta; a; b)

Arguments

  • probability:
    Cumulative probability (0–1).

  • alpha:
    Shape parameter α (must be > 0).

  • beta:
    Shape parameter β (must be > 0).

  • a (optional):
    Lower bound of the interval (default = 0).

  • b (optional):
    Upper bound of the interval (default = 1).

Basic Examples

50th percentile (median) of a beta distribution

=BETA.INV(0.5; 2; 5)

95th percentile

=BETA.INV(0.95; 2; 5)

Bounded beta quantile

=BETA.INV(0.9; 3; 4; 0; 10)

Using cell references

=BETA.INV(A1; B1; C1)

Advanced Examples

Bayesian credible interval (lower bound)

=BETA.INV(0.025; Successes+1; Failures+1)

Bayesian credible interval (upper bound)

=BETA.INV(0.975; Successes+1; Failures+1)

A/B testing: 90% quantile of conversion rate

=BETA.INV(0.9; A_success+1; A_fail+1)

Reliability modeling (bounded variable)

=BETA.INV(0.95; 3; 4; 10; 20)

Validate inversion

=BETA.DIST(BETA.INV(p; α; β); α; β; TRUE)

Convert bounded quantile to 0–1 scale

=BETA.INV(p; α; β; a; b)

Edge Cases and Behavior Details

BETA.INV returns a value x within [a, b]

Accepts:

  • 0 ≤ probability ≤ 1
  • α > 0
  • β > 0

Behavior details

  • If probability = 0 → returns a
  • If probability = 1 → returns b
  • Quantile is monotonic increasing
  • Bounded form rescales internally
  • Sensitive to extreme α/β values

Invalid input → Err:502

BETA.INV of an error → error propagates

Common Errors and Fixes

Err:502 — Invalid argument

Cause:

  • α ≤ 0 or β ≤ 0
  • probability outside 0–1
  • a ≥ b
  • Non-numeric input

Fix:

  • Validate α and β
  • Clamp probability to [0,1]
  • Ensure a < b

Unexpected extreme values

Cause:

  • Highly skewed distributions
  • α or β very small

Fix:

  • Inspect distribution shape
  • Use BETALN for stable log‑space modeling

Best Practices

  • Use BETA.INV for quantiles and credible intervals
  • Use BETA.DIST for PDF/CDF
  • Validate α and β to avoid domain errors
  • Use bounded form for real‑world ranges
  • Combine with BETALN for stable log‑likelihoods
BETA.INV is essential for Bayesian credible intervals, A/B testing thresholds, and any workflow requiring percentiles of a bounded probability distribution.

Related Patterns and Alternatives

  • Use BETA.DIST for PDF/CDF
  • Use BETALN for stable log‑beta calculations
  • Use GAMMALN for stable gamma‑function calculations
  • Use NORM.INV, F.INV, and GAMMA.INV for other quantile functions

By mastering BETA.INV, you can build powerful statistical, Bayesian, and probability‑driven models in LibreOffice Calc.

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