Understanding Excel's Quartile Functions

Microsoft Excel is the most widely used tool for data analysis, but its quartile calculations can be confusing because it offers multiple functions that yield different results. This calculator is designed to match Excel's logic perfectly.

QUARTILE.INC vs. QUARTILE.EXC

Since Excel 2010, Microsoft has provided two distinct functions to replace the legacy `QUARTILE` function:

1. QUARTILE.INC (Inclusive)

This is the default behavior of the legacy `QUARTILE` function. It uses an (N-1) basis for interpolation.

• Logic: It assumes the minimum value is the 0th percentile and the maximum value is the 100th percentile.
• Use Case: Best for everyday business reporting and when you want to ensure the percentiles fall within the range of your data.
• Python Equivalent: `numpy.percentile(data, q, method='linear')` (Default in older NumPy versions, but now often referred to as 'linear' on 0-100 scale).

2. QUARTILE.EXC (Exclusive)

This function uses an (N+1) basis for interpolation.

• Logic: It excludes the 0th and 100th percentiles, effectively assuming the data represents a sample from a larger population.
• Limitation: It cannot calculate quartiles for very small datasets (e.g., N < 4) because the required interpolation points would fall outside the data range.
• Use Case: Preferred by some statisticians for inferential statistics.

Why use this Online Excel Calculator?

If you don't have Excel installed, or if you are on a mobile device, this tool allows you to verify QUARTILE.INC results instantly. It is particularly useful for:

• Verifying spreadsheet formulas without opening Excel.
• Comparing Excel's output against R or Python standards.
• Visualizing the data with a box plot (which Excel requires multiple steps to create).

PlotNerd's Excel Quartile Calculator is specifically programmed to match Excel's QUARTILE.INC logic, making it perfect for verifying Excel results or calculating quartiles when you don't have access to Excel.

Better Than Excel's Box Plot?

While Excel is great for spreadsheets, creating a Box and Whisker Plot can be frustrating. You have to format data perfectly, select specific columns, and even then, customizing the outlier logic is difficult.

PlotNerd vs. Excel Box Plots:

• Speed: PlotNerd generates a box plot instantly from raw text. Excel requires data formatting and multiple clicks.
• Transparency: We show you the exact Q1, Median, and Q3 values. Excel's chart often hides the underlying numbers.
• Flexibility: Switch between inclusive (Excel default) and exclusive (scientific) methods with one click.