TRUNC Function in Excel: A Comprehensive Guide

Excel’s TRUNC function, a lesser-known yet powerful tool, plays a critical role in fields where precision in numerical data is vital. This function, standing for ‘truncate’, efficiently truncates a number to a specified number of decimal places without rounding. This precision is essential in various professional realms, particularly in financial calculations and data analysis, where even a minor rounding error can lead to significant discrepancies.

In this article, we delve into the nuances of the TRUNC function, exploring its practical applications and distinct advantages over similar functions like ROUND and INT. Whether you’re a financial analyst, data scientist, or Excel enthusiast, mastering the TRUNC function will enhance your data manipulation capabilities, leading to more accurate and reliable outcomes in your Excel tasks.

Understanding the TRUNC Function

Definition of the TRUNC Function

The TRUNC function in Excel is a Math and Trigonometry function that helps you truncate a given number to a specific decimal place. It essentially removes the fractional part of a decimal number, leaving only the integer part.

Comparing TRUNC to Other Functions like INT or ROUND

It’s important to note that the TRUNC, INT and ROUND functions can return the integer part of a number. However, they differ when dealing with negative numbers. To illustrate the differences and similarities between the TRUNC, INT, and ROUND functions in Excel, let’s use -+3.7 and -3.7 for this comparison. These examples will help highlight how each function handles both positive and negative numbers.

TRUNC Function in Excel

TRUNC Function truncates the number to the integer part, without rounding. INT Function rounds a number down to the nearest integer (Note: INT rounds negative numbers down to the next lower integer.) ROUND Function rounds a number to a specified number of digits (here rounded to 0 decimal places).

When handling positive values

  • TRUNC and INT give the same result for positive numbers, simply removing the decimal part.
  • ROUND considers the decimal value and rounds up if the decimal is 0.5 or more.

When handling negative numbers

  • TRUNC removes the decimal part without changing the sign or value of the integer part.
  • INT rounds negative numbers down to the next lower integer.
  • ROUND rounds negative numbers to the nearest integer based on the decimal value.
The TRUNC function consistently eliminates the decimal part, maintaining the integer portion unchanged regardless of the number's sign. On the other hand, the INT function always rounds down to the nearest integer, a trait particularly evident with negative numbers where it moves to the next lower integer. Contrastingly, the ROUND function is unique in its consideration of the decimal value, rounding to the nearest integer based on the decimal part's magnitude and direction, thus altering the integer portion for both positive and negative numbers depending on whether the decimal part is 0.5 or more (or its negative equivalent).

Syntax of the TRUNC Function

It’s essential to understand its parameters. The two parameters used by the TRUNC function are identified as number and num_digits.

  • Number: This is the value you want to truncate. It could be a number, cell address, or formula that returns a numeric value.
  • Num_digits: This argument signifies the number of digits you want to keep after truncating. If this argument is omitted, Excel uses 0 as the default value, meaning it removes all decimal places from the number.

Understanding these arguments allows you to effectively utilize the TRUNC function on your worksheet. By specifying different values for number and num_digits, you can control how Excel truncates your data and obtain your desired result.

Example: Truncating a number to two decimal places: If you have a value like 123.4567 and you want to truncate it to two decimal places, using

=TRUNC(123.4567, 2) 

will return 123.45.

Practical Applications of the TRUNC Function

Precise Data Reporting with TRUNC

In the realm of financial data reporting, the TRUNC function in Excel proves to be an invaluable asset for ensuring precision, especially when presenting key metrics like Earnings Per Share (EPS). Accurate data reporting is critical, as it directly influences investor trust and company valuation. For instance, consider a company with a net income of $2,500,000 and 1,000,000 shares outstanding. The EPS, a crucial indicator of profitability, would be calculated as $2,500,000 / 1,000,000 = $2.50. By employing the TRUNC function (=TRUNC(2500000 / 1000000, 2)), the EPS is precisely reported as $2.50, with the result truncated to two decimal places.

This approach is essential in financial reporting, as it eliminates any rounding discrepancies, ensuring that shareholders and analysts receive a transparent and exact representation of the company’s earnings per share. The use of TRUNC, therefore, not only upholds the accuracy of the financial data but also reinforces the credibility of the reports issued to stakeholders.

Using TRUNC in Financial Analysis

In financial analysis, the application of Excel’s TRUNC function can be a game-changer, particularly in refining the precision of critical financial calculations. Let’s consider its application in analyzing investment returns. Suppose an analyst is evaluating the daily returns of a stock portfolio, where even minuscule variations can significantly impact the long-term performance assessment. If a portfolio’s return one day is calculated as 1.857%, it’s essential to standardize the return format to two decimal places for precise analysis. Here, the TRUNC function can be applied (=TRUNC(1.857, 2)) to truncate the return to 1.85% without rounding.

This precision ensures that when these daily returns are aggregated or compared over time, the analysis is based on consistent and unrounded data, offering a more accurate picture of the portfolio’s performance. By using TRUNC, financial analysts can avoid the subtle yet impactful distortions that rounding might introduce, leading to more reliable and trustworthy financial analyses.

Using TRUNC with Date and Time values

Using the TRUNC function with date and time values in Excel effectively separates dates from times, which is particularly useful in scheduling, project planning, and time-tracking analyses. In Excel, dates and times are stored as serial numbers; dates are represented as whole numbers, and times as fractional values. Suppose you have a cell containing a date-time value like 7/15/2023 13:45. To isolate the date component, you would use the TRUNC function, like =TRUNC(A1).

This formula would truncate the decimal part (representing the time) and return just the date, 7/15/2023. This application is particularly valuable when you need to analyze or report on data based on dates without the time component. Applying TRUNC to date-time values ensures that your data is consistent and focused solely on the date aspect, enabling clearer and more accurate time-based analyses or visualizations.


The TRUNC function is a valuable tool in Excel for maintaining numerical precision. Its ability to truncate numbers without rounding is crucial in various professional fields, especially where accuracy is non-negotiable. With the insights and examples provided in this guide, you are now equipped to utilize the TRUNC function effectively in your Excel endeavors.

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