PlanMaker GEOMEAN: Positive Values and Compound Growth Factors

• Introduced: Documented by the PlanMaker 2010 manual; the first introduction release is not established.
• Availability: Documented in PlanMaker 2026; this is not a final working-version endpoint.
• Scope: The reference belongs to the 2026/NX manual family. Individual FreeOffice and mobile-build availability remains unverified.
• Checked: October 14, 2026, against the official function reference. Examples use vendor results and independent calculations; no native PlanMaker test was performed.

=GEOMEAN(Number1 [, Number2, Number3 ...])

The official GEOMEAN reference defines the geometric mean as the n-th root of the product of n values. Every evaluated value must be greater than zero. Individual values, ranges and arrays are accepted; the current signature requires the first argument and makes further ones optional.

The reference distinguishes cells from direct arguments: empty, text and logical cells are ignored, while directly entered text or logical arguments can be taken into account. It does not give a complete conversion table. Use positive numeric cells for the exercises below and do not assume that a negative rate belongs directly in a geometric-mean input range.

Create a blank sheet named Means. Put Observation and Positive value in A1:B1. Enter labels A, B, C in A2:A4 and numeric values 1, 2, 6 in B2:B4.

Use these output cells:

The three mean formulas answer different averaging questions. Their values need not agree. The product-root check makes GEOMEAN’s multiplicative definition visible without replacing it with an arithmetic mean.

For an exact-root control, enter 2 in F2 and 8 in F3. Put =GEOMEAN(F2:F3) in H2 and =(F2*F3)^(1/2) in H3. Both mathematical targets are 4, whereas the arithmetic average is 5.

Create a separate sheet named Growth. Put Period, Rate and Growth factor in A1:C1. Enter periods 1, 2, 3 in A2:A4 and rates 10%, −10%, 20% in B2:B4. Put =1+B2 in C2 and fill to C4.

Expected factors are 1.1, 0.9, 1.2. Each is positive, even though the middle rate is negative. Use these formulas:

Format E4 and E6 as percentages if desired: approximately 5.91045006% and 6.66666667%. The geometric equivalent rate reproduces the compounded change; the arithmetic average of the three rates does not.

Put 1000 in G2, =G2*E2 in G3 and =G2*E3^3 in G4. Both models give approximately 1188. They use the same three equal-length periods and assume no deposits, withdrawals or fees. They are mathematical examples, not forecasts.

Passing B2:B4 directly to GEOMEAN would include a negative value and violate the documented domain. A loss rate greater than −100% can still yield a positive growth factor; a factor of zero is outside this function’s stated input domain.

On another blank sheet, put 25% in A2 and −20% in A3. Enter =1+A2 in B2 and fill to B3. The factors 1.25 and 0.8 have product 1.

In D2 enter =GEOMEAN(B2:B3)-1; the expected equivalent rate is 0%. In D3 enter =AVERAGE(A2:A3); expect 2.5%. The arithmetic rate average is positive even though the two-period sequence returns to its starting value.

The 2010 manual documents the same positive-domain definition and 1,2,6 example. Its signature puts two arguments before the optional bracket; the current reference puts only the first there. The exact release of that presentation change is unknown, and it does not prove how every older engine treated a single argument.

The current entry does not specify every native error token for zero, negatives, empty ranges or extreme products. A conceptual product-root formula can encounter different intermediate numeric limits from a built-in implementation. Retain full precision and do not require identical last bits for arbitrary data.

AVERAGE is the arithmetic mean. HARMEAN averages through reciprocals, useful for appropriate rate models. PRODUCT exposes the multiplicative total used here.