ISODD in Excel: Odd-Number Tests and Alternating Positions
Check odd integers and truncated decimals in Excel, validate strict integer IDs and build transparent alternating-position formulas.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
Quick answer: =ISODD(7) is TRUE and =ISODD(8) is FALSE. Decimal inputs are truncated first, so =ISODD(7.8) is also TRUE even though 7.8 itself is not an integer.
Availability and version history
- Introduced: first introduction version is not established by the official history reviewed; the current product list is not a launch record.
- Availability: official help lists Excel for Microsoft 365, Excel for Microsoft 365 for Mac, Excel 2024, Excel 2024 for Mac, Excel 2021, Excel 2021 for Mac, Excel 2019, Excel 2016.
- Checked: October 14, 2026; official ISODD reference. Documentation and independently modeled examples; no native Excel execution or broader platform certification.
Syntax and returned value
=ISODD(number)
The number is required. Microsoft documents truncation for a noninteger input and #VALUE! for nonnumeric input. The result for an accepted numeric input is Boolean, not an odd integer. Use ODD when you actually want to round a value away from zero to an odd integer.
Example 1: signed and decimal controls
Enter the following in A2:A9. Use =TRUNC(A2) in B2 and =ISODD(A2) in C2, then fill down.
| Input | Truncated integer | Expected ISODD |
|---|---|---|
| 7 | 7 | TRUE |
| 8 | 8 | FALSE |
| 7.8 | 7 | TRUE |
| 8.8 | 8 | FALSE |
| -7.8 | -7 | TRUE |
| -8.8 | -8 | FALSE |
| 0 | 0 | FALSE |
| -0.8 | 0 | FALSE |
The sign does not change integer parity, and zero is even. For a negative decimal, however, the choice of integer transformation matters: TRUNC(-7.8) is -7, whereas INT(-7.8) is -8. Therefore ISODD of the first is TRUE and of the second is FALSE.
A common mistake is to read TRUE for 7.8 as evidence that the input is a whole number. ISODD has already discarded its fractional part before answering.
Example 2: accept only whole odd IDs
Suppose an internal field permits positive odd integer IDs, not fractions or numeric-looking text. In D2 use:
=IF(ISNUMBER(A2),IF(A2>0,IF(A2=TRUNC(A2),ISODD(A2),FALSE),FALSE),FALSE)
For the eight controls above, only 7 passes. A further ="7" text control fails the type requirement, and =NA() also fails rather than becoming a valid ID. Negative odd integers are rejected by this particular field policy even though their parity is odd.
If your field legitimately allows negative IDs, remove the positivity branch. The formula’s separate numeric, sign, integrality and parity checks make that change visible and reviewable.
Example 3: identify alternating data positions
Put six record names in F2:F7: Aster, Birch, Cedar, Dogwood, Elm, Fir. In G2 use and fill:
=ISODD(ROW()-ROW($F$2)+1)
The expression inside ISODD produces positions 1, 2, 3, 4, 5, 6. Expected results are TRUE, FALSE, TRUE, FALSE, TRUE, FALSE. If these are helper flags for manual review, Aster, Cedar and Elm are flagged.
The subtraction anchors the first data row at position one. By contrast, =ISODD(ROW()) uses actual worksheet row numbers 2–7 and gives FALSE, TRUE, FALSE, TRUE, FALSE, TRUE. Those are different questions, so explicitly choose the intended origin.
This position formula does not renumber only visible rows after filtering. It also changes a record’s assigned parity if the record moves to a different worksheet position. For stable classification, test a validated integer ID stored with the record instead.
Example 4: audit the odd/even partition
For the integers -3, -2, -1, 0, 1, 2, 3, the ISODD results are TRUE, FALSE, TRUE, FALSE, TRUE, FALSE, TRUE. There are four odd integers and three even integers.
For each accepted numeric input, compare =ISODD(A2) with =NOT(ISEVEN(A2)); the parity rules agree on these controls. Do not extend this Boolean comparison into a claim that nonnumeric input produces FALSE: it can produce an error instead.
Errors and scope
=ISODD("East") is a nonnumeric #VALUE! control. Numeric-text, Boolean and blank coercion details remain outside the dedicated examples; the strict workflow avoids relying on them. Very large integer identifiers also need precision care before any parity test.
References and verification
The datasets are fictional. Expected results follow the cited rules and independent arithmetic or type models; they are not native application captures. Examples use English function names and comma argument separators.