Calculation Issues

How to Fix the 3.55E-15 Floating-Point Error in Excel

WPS Content Manager Sep 28, 2026 868 views

Question details

The user needs to correct microscopic residual values caused by floating-point calculation limitations in spreadsheet software.

How to Fix the 3.55E-15 Floating-Point Error in Excel

Product: Excel
Device & OS: not provided
Scenario: Calculating time and complex numeric values where the expected final result should be an exact zero.
Observed behavior: The formula calculation returns a microscopic scientific notation value, such as 3.55E-15, rather than exactly zero.

Before you start

Determine the exact number of decimal places your data actually requires, as you will need to specify this number when applying the rounding fix to your formula.

Solution 1Recommended

Use the ROUND Function to Eliminate Residual Values

Wrapping your entire formula in the ROUND function forces the spreadsheet program to discard microscopic binary artifacts and output the true exact number.

Spreadsheet applications store and calculate numbers in binary format. This conversion can sometimes leave a tiny residual fraction (like 3.55E-15, which means 3.55 × 10⁻¹⁵) instead of an absolute zero.

By applying the ROUND function, you can strip away these unwanted microscopic decimals without changing the core logic of your equation.

Select the target cell

Click on the cell containing the formula that is returning the 3.55E-15 error.

Edit the formula

Click into the formula bar located at the top of your workspace, just above the column headers.

Insert the ROUND function

Type ROUND( immediately following the equals sign (=) of your existing formula.

Specify decimal places

At the very end of your existing formula, add a comma followed by the number of decimal places you need (e.g., , 2), then close the parenthesis and press Enter. For example: =ROUND(IF(SUM(F84:O84)-(((C84-B84)*24)*S84)>=0,SUM(F84:O84)-(((C84-B84)*24)*S84),0), 2).

Use the ROUND Function to Eliminate Residual Values

Formula Formatting Tip: If you are calculating time and strictly need an exact zero instead of fractions of a second, setting the decimal argument in the ROUND function to 0 or 2 will effectively solve the issue in subsequent calculations.

Precision Calculations in WPS Office

Use WPS Spreadsheet for Accurate Formula Calculations

WPS Spreadsheet features an advanced calculation engine that perfectly handles complex math, time formatting, and logical functions. It provides a familiar interface to easily wrap your existing formulas in ROUND, ensuring precise data reporting without microscopic residual errors.

1. Open your file: Launch WPS Spreadsheet and open the document containing your formulas.
2. Locate the formula: Select the cell showing the floating-point error and click into the formula bar.
3. Apply rounding: Modify the equation to include the ROUND function (e.g., =ROUND(A1-B1, 2)) and press Enter.

Fully compatible with Microsoft Excel formulas and file formats (.xlsx)Comprehensive library of built-in mathematical and logical functionsLightweight, fast, and completely free to useIntuitive formula bar with helpful syntax prompts

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Frequently Asked Questions

Why does Excel show an 'E' in my calculated numbers?

The 'E' stands for scientific notation (exponent). When a number is incredibly small, such as 3.55E-15, it actually represents 3.55 × 10⁻¹⁵. Excel displays it this way because the number has 14 zeros before the first significant digit, which is virtually zero but technically a floating-point artifact.

Can I fix floating-point errors by just changing the cell formatting?

No. While changing the cell format to 'Number' with fewer decimal places will visually hide the 3.55E-15 and display '0.00', the microscopic value remains in the cell's memory. This hidden decimal can cause errors in subsequent formulas that rely on an exact zero. Using the ROUND function permanently addresses the underlying value.

Is there a setting to automatically prevent floating-point errors?

Yes, you can enable 'Set precision as displayed' in your spreadsheet's Advanced Options. However, you should use this feature with extreme caution. It permanently changes all stored values in the entire workbook to match their displayed precision, which can lead to unintended data loss in other accurate calculations.

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