How to use the ISNA function

What is the ISNA function?

The ISNA function returns TRUE if the returned value is a #N/A error.

1. Introduction

What is a #N/A error?

The #N/A error happens when a value is not available for a formula or found in a given cell range, for example in the VLOOKUP or MATCH functions.

What is a Boolean value?

A Boolean value in Excel is a value that can only be TRUE or FALSE. It represents binary logic and is the result of a logical expression using logical operators or a result of a few Excel functions like ISNA function that I'll discuss below. Mastering Boolean logic and logical expressions is key to manipulating data and controlling workflow in Excel.

• Boolean value TRUE has the numerical equivalent of 1.
• Boolean value FALSE has the numerical equivalent of 0 (zero).

All functions that begins with IS return boolean value TRUE or FALSE. The IF function and SUMPRODUCT function are two functions of many that use boolean logic to calculate an output value.

In Excel, you can use the logical operators AND and OR to combine boolean values (TRUE and FALSE) to create more complex logical expressions. Here's how they work:

1. AND Logic: The AND operator returns TRUE if all the conditions it is evaluating are TRUE, and FALSE if any of the conditions are FALSE.
   The syntax for the AND function in Excel is: =AND(logical1, [logical2], ...)
   Example: =AND(A1=10, B1>5)
   This will return TRUE only if the value in cell A1 is 10 AND the value in cell B1 is greater than 5.
2. OR Logic: The OR operator returns TRUE if any of the conditions it is evaluating are TRUE, and FALSE if all the conditions are FALSE.
   The syntax for the OR function in Excel is: =OR(logical1, [logical2], ...)
   Example: =OR(A1=10, B1>5)
   This will return TRUE if either the value in cell A1 is 10 OR the value in cell B1 is greater than 5.

Here are some examples using boolean values:

• =AND(TRUE, TRUE) - Returns TRUE
• =AND(TRUE, FALSE) - Returns FALSE
• =OR(TRUE, FALSE) - Returns TRUE
• =OR(FALSE, FALSE) - Returns FALSE

You can also use these logical operators in combination with other Excel functions, such as IF statements, to create more complex conditional logic. For example:

• =IF(AND(A1>0, B1>0), "Both Positive", "Not Both Positive")
• =IF(OR(A1>0, B1>0), "At Least One Positive", "Neither Positive")

Understanding AND and OR logic in Excel can be very useful when you need to perform complex data analysis or make decisions based on multiple conditions.

Other IS functions

Excel Function	Description
ISBLANK(value)	Returns TRUE if the value is empty, FALSE otherwise
ISERR(value)	Returns TRUE if the value is any error value except #N/A, FALSE otherwise
ISERROR(value)	Returns TRUE if the value is any error value, FALSE otherwise
ISEVEN(value)	Returns TRUE if the value is an even number, FALSE for odd numbers
ISFORMULA(reference)	Returns TRUE if the cell contains a formula, FALSE otherwise
ISLOGICAL(value)	Returns TRUE if the value is a logical value (TRUE/FALSE), FALSE otherwise
ISNA(value)	Returns TRUE if the value is the #N/A error, FALSE otherwise
ISNONTEXT(value)	Returns TRUE if the value is not text, FALSE if it is text
ISNUMBER(value)	Returns TRUE if the value is a number, FALSE otherwise
ISODD(value)	Returns TRUE if the value is an odd number, FALSE for even numbers

2. Syntax

ISNA(value)

value

Required. A cell reference pointing to the value you want to check for #N/A error.

What is a cell reference?

A cell reference lets you "fetch" and use values in other cells in a formula.

There are two types of cell references:

• A1-style reference
• R1C1 reference

The A1-style reference is the default style in Excel, it names columns by letters from A to Z. After Z it starts over with AA, AB, and so on until XFD. Rows are numbered from 1 to 1048576, older Excel versions use less row numbers.

The R1C1-style uses row number and column number like: R1C1, R2C5 and R10C15. Rows are labeled R1, R2, R3 and so on, columns are labeled C1, C2, C3 etc.

The A1-style reference notation is the most common one, here are some examples:

A1 - single cell reference on the same worksheet
A1:D5 - reference to a cell range on the same worksheet
Budget!Z3 - a single cell reference to worksheet Budget
'Budget 2050'!A3 - a single cell reference to a worksheet containing a space character

There are two types of cell references:

• Relative cell references
• Absolute cell references

The examples above are all relative cell references, they change accordingly if a cell is copied and pasted to another cell which absolute cell references do not.

The $ dollar character lets you an absolute cell reference meaning you can lock a cell reference horizontally, vertically or both. Here is one example:

A$1 has a relative column reference but an absolute row reference, this means that the column letter may change if the cell is copied and pasted to cells in another column than A.

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3. Example 1

This image above demonstrates the behavior of Excel's ISNA function, which returns TRUE only when the input is the #N/A error value, and FALSE for all other inputs. Cell range B3:B9 contains input values and cell range C3:C9 contains the output fomr the ISNA function.

The first source value in cell B3 is a text value.

Formula in cell C3:

The output value in cell C3 is boolean value FALSE. Text value "A" is not equal to #N/A error value which results in boolean value FALSE.

Here is a break-down of the formulas in the remaining cells C4:C9:

• The source value in cell B4 is a numeric value. The output value in cell C4 is boolean value FALSE. Numeric value 1 is not equal to #N/A error value which results in boolean value FALSE.
• The source value in cell B5 is a #DIV/0! error value. The output value in cell C5 is boolean value FALSE. #DIV/0! error value is not equal to #N/A error value which results in boolean value FALSE.
• The source value in cell B6 is a #N/A error value. The output value in cell C6 is boolean value TRUE. #N/A error value is equal to #N/A error value which results in boolean value TRUE.
• The source value in cell B7 is a #VALUE! error value. The output value in cell C7 is boolean value FALSE. #VALUE! error value is not equal to #N/A error value which results in boolean value FALSE.
• The source value in cell B8 is a #NAME? error value. The output value in cell C8 is boolean value FALSE. #NAME? error value is not equal to #N/A error value which results in boolean value FALSE.
• The source value in cell B9 is a #REF! error value. The output value in cell C9 is boolean value FALSE. #REF! error value is not equal to #N/A error value which results in boolean value FALSE.

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4. Function not working

The ISNA function returns #NAME! error if you misspell the function name. It does not however propagate error values meaning an error is returned if the source data contains an error.

4.1 Troubleshooting the error value

When you encounter an error value in a cell a warning symbol appears, displayed in the image above. Press with mouse on it to see a pop-up menu that lets you get more information about the error.

1. The first line describes the error if you press with left mouse button on it.
2. The second line opens a pane that explains the error in greater detail.
3. The third line takes you to the "Evaluate Formula" tool, a dialog box appears allowing you to examine the formula in greater detail.
4. This line lets you ignore the error value meaning the warning icon disappears, however, the error is still in the cell.
5. The fifth line lets you edit the formula in the Formula bar.
6. The sixth line opens the Excel settings so you can adjust the Error Checking Options.

Here are a few of the most common Excel errors you may encounter.

#NULL error - This error occurs most often if you by mistake use a space character in a formula where it shouldn't be. Excel interprets a space character as an intersection operator. If the ranges don't intersect an #NULL error is returned. The #NULL! error occurs when a formula attempts to calculate the intersection of two ranges that do not actually intersect. This can happen when the wrong range operator is used in the formula, or when the intersection operator (represented by a space character) is used between two ranges that do not overlap. To fix this error double check that the ranges referenced in the formula that use the intersection operator actually have cells in common.

#SPILL error - The #SPILL! error occurs only in version Excel 365 and is caused by a dynamic array being to large, meaning there are cells below and/or to the right that are not empty. This prevents the dynamic array formula expanding into new empty cells.

#DIV/0 error - This error happens if you try to divide a number by 0 (zero) or a value that equates to zero which is not possible mathematically.

#VALUE error - The #VALUE error occurs when a formula has a value that is of the wrong data type. Such as text where a number is expected or when dates are evaluated as text.

#REF error - The #REF error happens when a cell reference is invalid. This can happen if a cell is deleted that is referenced by a formula.

#NAME error - The #NAME error happens if you misspelled a function or a named range.

#NUM error - The #NUM error shows up when you try to use invalid numeric values in formulas, like square root of a negative number.

#N/A error - The #N/A error happens when a value is not available for a formula or found in a given cell range, for example in the VLOOKUP or MATCH functions.

#GETTING_DATA error - The #GETTING_DATA error shows while external sources are loading, this can indicate a delay in fetching the data or that the external source is unavailable right now.

4.2 The formula returns an unexpected value

To understand why a formula returns an unexpected value we need to examine the calculations steps in detail. Luckily, Excel has a tool that is really handy in these situations. Here is how to troubleshoot a formula:

1. Select the cell containing the formula you want to examine in detail.
2. Go to tab “Formulas” on the ribbon.
3. Press with left mouse button on "Evaluate Formula" button. A dialog box appears.
   The formula appears in a white field inside the dialog box. Underlined expressions are calculations being processed in the next step. The italicized expression is the most recent result. The buttons at the bottom of the dialog box allows you to evaluate the formula in smaller calculations which you control.
4. Press with left mouse button on the "Evaluate" button located at the bottom of the dialog box to process the underlined expression.
5. Repeat pressing the "Evaluate" button until you have seen all calculations step by step. This allows you to examine the formula in greater detail and hopefully find the culprit.
6. Press "Close" button to dismiss the dialog box.

There is also another way to debug formulas using the function key F9. F9 is especially useful if you have a feeling that a specific part of the formula is the issue, this makes it faster than the "Evaluate Formula" tool since you don't need to go through all calculations to find the issue..

1. Enter Edit mode: Double-press with left mouse button on the cell or press F2 to enter Edit mode for the formula.
2. Select part of the formula: Highlight the specific part of the formula you want to evaluate. You can select and evaluate any part of the formula that could work as a standalone formula.
3. Press F9: This will calculate and display the result of just that selected portion.
4. Evaluate step-by-step: You can select and evaluate different parts of the formula to see intermediate results.
5. Check for errors: This allows you to pinpoint which part of a complex formula may be causing an error.

The image above shows cell reference B3:B4 converted to hard-coded value using the F9 key. The ISNA function requires empty cells below the destination cell which is not the case in this example. We have found what is wrong with the formula.

Tips!

• View actual values: Selecting a cell reference and pressing F9 will show the actual values in those cells.
• Exit safely: Press Esc to exit Edit mode without changing the formula. Don't press Enter, as that would replace the formula part with the calculated value.
• Full recalculation: Pressing F9 outside of Edit mode will recalculate all formulas in the workbook.

Remember to be careful not to accidentally overwrite parts of your formula when using F9. Always exit with Esc rather than Enter to preserve the original formula. However, if you make a mistake overwriting the formula it is not the end of the world. You can “undo” the action by pressing keyboard shortcut keys CTRL + z or pressing the “Undo” button

4.3 Other errors

Floating-point arithmetic may give inaccurate results in Excel - Article

Floating-point errors are usually very small, often beyond the 15th decimal place, and in most cases don't affect calculations significantly.

'ISNA' function examples

Functions in 'Information' category

The ISNA function function is one of 19 functions in the 'Information' category.

Excel function categories

Excel categories

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