LOG10 in SoftMaker PlanMaker: base-10 logarithms

The common logarithm answers questions about powers of ten: LOG10(1000)=3, LOG10(1)=0, and LOG10(0.01)=-2. A negative logarithm result is normal for a positive input between zero and one; it is not an error. A nonpositive input, by contrast, is outside the documented real-number domain. 2026 reference.

Use LOG10 for orders of magnitude, charts with logarithmic scales, scientific measurements with large value ranges, and ratios expressed in decibels. If you need a natural logarithm, use LN. If you need a configurable base, PlanMaker documents LOG(Number [, Base]), which defaults to base 10 when the second argument is omitted. PlanMaker LOG; LN (checked October 13, 2026).

=LOG10(Number)

No optional parameter, base parameter, or default argument exists in the official LOG10 syntax. LOG10(100,2) is not the documented way to calculate log base 2; use the separate LOG function with a base argument. The English-language help uses LOG10(Number); enter the initial = when typing a worksheet formula. SoftMaker 2026 LOG10; SoftMaker 2026 LOG; Entering formulas.

In a new worksheet, type these headers and numeric inputs, then the listed formulas. Row labels are text, values in B are numeric (not strings such as '0.01). All calculated answers below are independently expected, not observed application output.

1. Enter headings in A1:C1 and the exact numeric values in B2:B7; text row labels go in column A.
2. Type =LOG10(B2) in C2. Copy downward through C7, retaining relative B-row references.
3. Display at least six decimals in C5/C7 if you want to compare noninteger results. PlanMaker’s number formatting can change displayed decimals without rounding the stored calculation, as its number-format documentation explains.
4. Use =10^C2 in a spare cell to reconstruct B2. The expected result is 1000. For more sensitive comparisons, allow for numerical rounding instead of exact equality.

SoftMaker itself provides LOG10(100) = 2 and LOG10(10^0.1234) = 0.1234. We use different inputs above to add meaningful independent examples. 2026 LOG10 function reference (checked October 13, 2026).

Quantify a multiplicative difference in orders of magnitude

Suppose a before-value of 100 is in B10 and an after-value of 100000 is in C10. In D10 type:

=LOG10(C10/B10)

Expected: 3 because the ratio is 1000 and 10^3 = 1000. The output represents a three-order-of-magnitude increase, not three times as large or a 3% change. Both original values must be positive, and the ratio must also be positive. This is mathematics based on the documented base-10 definition, not a PlanMaker application test.

Calculate a power ratio in decibels

Put a positive reference power 2 in B11 and a positive comparison power 20 in C11, with the same physical units. For a power ratio use:

=10*LOG10(C11/B11)

Expected: 10 dB. For a power ratio of 2 rather than 10, the independent result is 10*LOG10(2) ≈ 3.010299957 dB. The factor of 10 here is for power ratios; different quantities (such as amplitudes under particular assumptions) may require a factor of 20 and must not be substituted without physical context. The formula is a domain-specific mathematical application of LOG10 and is not an application-specific SoftMaker endorsement.

Recover a value from its logarithm

Suppose C5 contains LOG10(5) from the table. Enter:

=10^C5

The independently expected value is approximately 5. Due to finite precision, do not assert byte-for-byte equality with B5; instead use a reasonable tolerance such as =ABS((10^C5)-B5)<0.0000001 if your context supports such a tolerance. The ^ exponential operator and the inverse relation follow ordinary logarithm arithmetic; PlanMaker’s POWER function documentation describes the named power function separately.

Compare related functions without assuming aliases

=LOG10(100) and =LOG(100) both have an independently expected value of 2, because SoftMaker says LOG defaults to base ten. =LOG(8,2) gives 3, which LOG10 does not offer as a two-argument call. =LN(EXP(1.234)) has a documented expected result of 1.234 but uses natural logarithms, not base ten. These are different function identities, not duplicate pages. LOG; LN; EXP.

SoftMaker explicitly documents positive inputs but does not enumerate all exact displayed error codes for zero, negative arguments, nonnumeric text, missing arguments or overflow in the brief LOG10 entry. Therefore this guide does not attribute an Excel-specific #NUM! or #VALUE! outcome to PlanMaker without native verification. For general input errors, see PlanMaker formula-entry instructions and syntax highlighting/error classification (checked October 13, 2026).

Compatibility judgement: Both vendors document a single required positive numeric argument and a base-10 logarithm result. Workbook import/export, localized naming, formula rewriting, exact error codes, extreme-value precision and every operating-system edition require separate native testing.

• LOG — optional explicit base; defaults to 10 according to the official manual.
• LN — natural log with base e, not base 10.
• EXP — powers of e, natural logarithm’s inverse.
• POWER — power calculation.
• PlanMaker number formatting — displayed precision versus stored values.
• Microsoft Excel LOG10 — independent comparator.

Checked October 13, 2026: Official SoftMaker PlanMaker 2026 and 2024 LOG10 pages, 2026 LOG/LN/EXP/POWER, PlanMaker formula-input and number-format guidance, plus separate Microsoft Excel LOG10 documentation. The companion evidence record maps specific claims to these official pages. Application runs: PlanMaker 0, Excel 0. Numeric outputs above are from independent calculations of base-10 logarithms and related arithmetic; no screenshots or observed execution are claimed.