BETAINV Function (Calligra Sheets)

• Introduced: First release not established; the name is present in Calligra 2.4.0 source.
• Supported in: Calligra Sheets 26.08.2, with no retirement established.
• Scope: Desktop Sheets with the Statistical module. Examples use English semicolon-separated formulas.
• Checked: October 14, 2026. Selected formulas ran through the official 25.04.2 engine library. Source and independent mathematics were checked. This is engine evidence, with no GUI-cell or import verification; 26.08.2 was source-checked only.

BETAINV numerically inverts the cumulative BETADIST operation. The first argument is a lower-tail probability. It is not the inverse of the defective density branch and does not use an upper-tail convention. Optional bounds transform a unit-interval quantile into the desired interval. Function help.

=BETAINV(probability;alpha;beta[;lower[;upper]])

Probability, alpha and beta are required. Lower and upper default to 0 and 1. Use 0≤probability≤1, strictly positive shapes and lower<upper for a beta-distribution interpretation. The wrapper rejects negative shapes, but its guard does not reject zero shapes; zero is still not a valid beta-distribution shape and was not validated as usable here. Brackets indicate optional arguments and are not entered in the formula. Registration and implementation.

The engine and mathematical columns are separate. Results are rounded to twelve decimal places, or thirteen significant digits in scientific notation for very small or large values. This is a display choice, not an accuracy guarantee. NaN and infinity are nonfinite outputs; an engine error flag is checked separately from those values.

For shapes 2 and 3, the median is approximately 0.385727568132 in independent mathematics. It is not 0.5 because the distribution is asymmetric. The native result is shown separately so the solver’s finite precision remains visible.

Scaling to [10,14] uses 10+4t. The median is therefore approximately 11.542910272529. Enter a lower-tail probability such as 0.5, not a percentage written as the whole number 50. For the uniform shapes 1 and 1 on [0,1], the quantile equals the probability itself.

A cumulative/inverse roundtrip is a useful internal check: the listed composition returns 0.5 in the tested engine. It verifies consistency between those two implementations for that input; it is not independent proof of every printed decimal. Both calls share the same cumulative helper.

For valid bounds, endpoint probabilities 0 and 1 map to lower and upper. The retained [10,14] diagnostics return 10 and 14. The solver operates on the unit interval before applying the final linear transformation, so an interval-width error would affect every non-endpoint result.

The executed advanced check was:

=BETADIST(BETAINV(0.5;2;3);2;3)

Its engine result was 0.5.

Equal bounds and outside-domain probabilities give errors in the listed cases. Reversed bounds are accepted by the implementation and produce a decreasing affine transformation; do not treat that as a valid beta interval. The shared iterator uses a fixed convergence tolerance, while the cumulative helper is itself approximate. Extreme probabilities, zero shapes and arbitrary large parameters are not certified by these ordinary cases.

• Function-specific implementation
• Versioned function help
• Beta helper
• Inverse helper

The statistical module and value-calculation helpers are byte-identical between the inspected 25.04.2 and 26.08.2 sources. That comparison supports the source discussion but does not establish later-version native output, every locale or arbitrary extreme-parameter accuracy.

NORMINV, NORMDIST.