LOG2 in Calligra Sheets: Base-2 Logarithms and Binary Capacity

LOG2 answers “to what power must 2 be raised to obtain this positive number?” For example, =LOG2(32) has an expected result of 5, because 2⁵ = 32. It is useful for binary-capacity questions and comparisons between successive doublings. This is a documented Calligra function and not the same syntax as Excel’s custom-base LOG(32,2).

=LOG2(x)

• x (required): one numeric floating-point input or reference, intended to be positive for a finite real logarithm. KDE’s parameter type is floating point; the handbook does not explicitly call it a positive-only argument.
• Base/defaults: the base is exactly 2; no second argument, base selector or default is documented.
• Return: floating-point base-2 logarithm; negative outputs are valid when 0 < x < 1.
• Important source nuance: KDE’s own handbook illustrates LOG2(0) as -inf, rather than using the wording “is an error” used for LOG(0) and LOG10(0). Do not assume this represents a finite, portable spreadsheet value; no native 26.08.2 run was performed to confirm its display/export behavior.

This guide is release-scoped to Calligra Sheets 26.08.2 (KDE’s release listing dated 2026-10-08). The function is present both in the official stable-KF6 function handbook and in KDE’s pinned 26.08.2 source-function registry; references were accessed 2026-10-11. The handbook’s surrounding revision may be older than the release: source registration documents that a name is available in that release’s code, not that it was executed or enabled in a particular Linux package or other platform. Calligra recommends Linux packages/Flatpak; installed versions and optional components can differ.

In a cell, start a formula with =. The KDE English documentation uses semicolon (;) as the multiple-argument separator; the examples use periods for decimal points. Actual entry conventions may vary with locale or build. Use the installed function selector to confirm locally and keep input columns numeric, not numeric-looking text. Results are floating-point values; displayed precision is controlled by cell formatting. All results below are expected mathematical values, not observed Calligra 26.08.2 outputs.

1. Set A1 to Positive value and B1 to Binary exponent.
2. Enter the numbers into A2:A6. In B2 type =LOG2(A2) and fill to B6.
3. The integer results appear because these inputs are exact powers of two. For non-powers, expect a fractional exponent; for a positive fraction below one, expect a negative exponent.

A useful fractional check is =LOG2(0.5), with expected −1. The source handbook also gives an example near −0.32192809 for LOG2(0.8).

To assign a different binary code to each of N distinct states, the minimum fixed code length is ceil(log₂(N)) bits for integer N ≥ 1, assuming no added check bits or reserved codes. the guide reuses the separately documented ROUNDUP function to round a nonnegative logarithm up to a whole number.

• Put N in D2, for example 3. In E2 enter =ROUNDUP(LOG2(D2);0); expected 2 bits, since 2² = 4 can represent three states.
• Put 8 in D3 and use =ROUNDUP(LOG2(D3);0); expected 3 bits.
• Put 9 in D4; expected 4 bits.
• Put 256 in D5; expected 8 bits.
• Put 1 in D6; expected 0 bits mathematically for a choice with only one possible state.

For practical systems, the result is only the theoretical bit count: storage framing, error detection, metadata and serialization may add overhead. A displayed approximation slightly above an integer at an exact power of two is a potential floating-point boundary concern; validate boundary cases natively before relying on a general imported workbook.

• Zero input: KDE’s published example says -inf for LOG2(0); avoid using zero rather than assuming a stable spreadsheet error token or portable infinity.
• Negative inputs: the real base-2 logarithm is undefined; the source does not establish which error cell a particular installation displays.
• Fractional results: LOG2(3) is about 1.584963, not 2. Use ROUNDUP(...;0) if the goal is bits needed to label discrete states, not if you need the mathematical logarithm itself.
• Unexpected base: LOG2(100) is not 2, because 2² ≠ 100. Use LOG10(100) for the common logarithm or LOGN(100;10) for an explicit base.
• Locale, text and rounding: ensure imported input is numeric, use appropriate decimal marks and test cell formatting. A displayed integer may conceal floating-point approximations.
• Near powers of two: independent Python values do not guarantee identical floating-point edge behavior in the Calligra calculation engine. Native tests must verify these edge cases before production.

Excel’s official LOG(number,[base]) accepts a second argument: its direct counterpart for a base-two log is LOG(number,2). LibreOffice Calc documents LOG(Number [; Base]), with the equivalent LOG(number;2) in its shown delimiter style. The Calligra handbook instead explicitly provides LOG2(x) and LOGN(value;base). A file containing Calligra’s LOG2 spelling should not be assumed to survive a cross-program conversion unchanged; use the destination program’s documented formula syntax and test the imported calculation. Calligra also provides LOG(x) and LOG10(x) for base ten.

The KDE handbook lists LN, LOG, LOG10 and LOGN as related functions. These are recorded as review/planned material rather than assumed published URLs. The existing owner-snapshot IF guide at content/calligra/functions/if.md is an available editorial internal-link target at IF in Calligra Sheets for positive-input checks; public availability was not verified.

• Calligra Sheets — function documentation
• official stable-KF6 function handbook
• KDE Calligra 26.08.2 source registration
• LibreOffice Calc mathematical functions

Verification status: Official documentation checked; example outcomes were independently reasoned or arithmetically checked where applicable. Not executed in Calligra Sheets.

• No genuine Calligra Sheets screenshots are included; this guide does not use mock application images.