QUARTILE & PERCENTILE Distribution Formulas
QUARTILE & PERCENTILE Distribution Formulas

QUARTILE & PERCENTILE Distribution Formulas

Learn customer segmentation and dataset distribution in Excel with QUARTILE.INC and PERCENTILE.INC. Understand .INC versus .EXC variants cleanly.

M. Ichsanul Fadhil
Published

QUARTILE & PERCENTILE Formulas

In e-commerce customer segmentation, employee performance reviews, and academic grading, you often need to divide a population into tiers: bottom 25% casual shoppers, middle 50% core customers, and top 10% elite VIPs.

Excel provides two companion distribution tools: QUARTILE (dividing data into 4 quarters) and PERCENTILE (dividing data into 100 hundredths). However, modern Excel presents both .INC (Inclusive) and .EXC (Exclusive) versions, creating confusion.

This guide explains the mechanics of percentiles, clarifies why .INC is the business standard, and shows how to set tier boundaries cleanly.

QUARTILE.INC (Quarters 0 to 4)

4-Tier Segmentation

Divides sorted numbers into quarters: Q1 (25%), Q2 (Median 50%), and Q3 (75%). Includes min and max endpoints.

PERCENTILE.INC (0.0 to 1.0)

Granular Percentile Ranks

Calculates arbitrary percentile boundaries (such as the 90th percentile for VIP tiers or 95th percentile for latency SLA).

Quick Comparison: .INC vs .EXC Variants

Variant Allowed k Range Endpoint Treatment Sample Size Sensitivity Best Application
.INC (Inclusive) 0.0 to 1.0 (0% to 100%) Includes Min (0) and Max (1) Works on small and large datasets 95% of business & finance reports
.EXC (Exclusive) Strictly between 0 and 1 Excludes Min and Max endpoints Triggers #NUM! if sample is too small Specialized academic statistical research

How the Quartile and Percentile Engines Work

1. Syntax of QUARTILE.INC

=QUARTILE.INC(array, quart)
  • quart = 0: Minimum value.
  • quart = 1: First Quartile (25th percentile).
  • quart = 2: Median value (50th percentile).
  • quart = 3: Third Quartile (75th percentile).
  • quart = 4: Maximum value.

2. Syntax of PERCENTILE.INC

=PERCENTILE.INC(array, k)

Where k is a decimal between 0 and 1 representing the percentile (e.g. 0.90 for the 90th percentile).

3. Mathematical Equivalence

Note that =QUARTILE.INC(Range, 1) produces the exact same value as =PERCENTILE.INC(Range, 0.25), and =QUARTILE.INC(Range, 2) matches =MEDIAN(Range).

Real-Life Workplace Scenarios

1. E-Commerce VIP Tiering

Marketing teams reward customers falling into the top 10th percentile (=PERCENTILE.INC(Spends, 0.90)) with exclusive platinum concierge benefits.

2. Server Performance Service Level Agreements (SLA)

Cloud service providers guarantee that 99% of web requests will resolve within a target latency threshold (=PERCENTILE.INC(Latencies, 0.99)).

Common Mistakes to Avoid

  • Accidentally Using .EXC on Small Data: Using PERCENTILE.EXC on small tables triggers a #NUM! error because the sample cannot support interior exclusion. Stick to .INC for reliable business spreadsheets.
  • Percentages Greater than 1: Passing 90 instead of 0.9 into PERCENTILE.INC triggers a #NUM! error.

Segment customer spending in our spreadsheet playground below.

Budget vs Actual Variance Analysis
Financial Planning
Applied Project Exercise

Ready to apply QUARTILE & PERCENTILE Distribution Formulas in a real workbook?

Analyze variance deviations, averages, and performance metrics across departments.

Open Budget vs Actual Variance Analysis
Tactical Arena
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