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Calculator · general

Linear Inches Calculator

Add length, width, and height to find total linear inches. Instantly check if luggage meets the standard 62-inch airline limit.

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Inputs

Length

Width

Height

Input Unit

Linear Inches

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Get a plain-English breakdown of your result with practical next steps.

Linear Inches—in

The formula

How the
result is
computed.

What Are Linear Inches?

Linear inches represent the sum of an object's three exterior dimensions — length, width, and height — combined into a single measurement. The formula is straightforward:

L_in = L + W + H

Where L is the longest side (length), W is the second longest side (width), and H is the shortest side (height or depth). Unlike volume, which multiplies all three dimensions, linear inches simply add them together to produce one number that expresses overall size at a glance.

Why Linear Inches Matter

Airlines rely on linear inches as the standard method for enforcing checked baggage size limits. Most major U.S. carriers — including American Airlines, Delta, United, and Southwest — enforce a 62 linear inch (158 cm) maximum for standard checked bags. A classic bag measuring 27 × 21 × 14 inches totals exactly 62 linear inches and fits within this limit.

Beyond air travel, linear inches appear in freight shipping, storage unit pricing, and archival record-keeping. According to UNLV Special Collections and Archives, librarians apply linear measurement to estimate how many inches of shelf space a collection occupies — a direct application of the same additive dimension method used here.

Step-by-Step Calculation Guide

Measure the length — the longest exterior dimension, taken at the widest point including any handles or structural overhangs.
Measure the width — the second longest dimension, perpendicular to the length. For a standing suitcase, this is usually the front-to-back depth.
Measure the height — the shortest dimension, often called depth. For a rolling suitcase, this is the side-to-side span.
Add all three values — the total is the linear inch measurement.

Example 1: Standard Carry-On Bag

A carry-on measures 22 × 14 × 9 inches. The calculation: 22 + 14 + 9 = 45 linear inches — exactly at the common carry-on threshold enforced by most U.S. airlines.

Example 2: Checked Luggage Within the Limit

A mid-size suitcase measures 28 × 20 × 12 inches. The calculation: 28 + 20 + 12 = 60 linear inches, comfortably under the standard 62-inch checked baggage limit.

Example 3: Oversized Item

A large trunk measures 32 × 24 × 16 inches. The total: 32 + 24 + 16 = 72 linear inches. This exceeds the airline limit by 10 inches, triggering oversized baggage fees that typically range from $100 to $200 per flight segment.

Variable Definitions

Length (L) — The longest exterior side of the item, measured end to end at the absolute widest point.
Width (W) — The second longest dimension, measured perpendicular to the length.
Height (H) — The shortest dimension, including any wheel housings or protruding handles on luggage.
Input Unit — The unit of measurement for all entered dimensions. The calculator automatically converts centimeter inputs by dividing by 2.54 before applying the formula.

Converting Centimeters to Linear Inches

To convert dimensions from centimeters to inches, divide each measurement by 2.54, then add the three results. A bag measured as 70 cm × 50 cm × 30 cm converts to approximately 27.6 + 19.7 + 11.8 = 59.1 linear inches — safely within the standard airline limit. The 62-inch limit equals exactly 157.48 centimeters, which international carriers typically round to 158 cm in their published policies.

Sources and Methodology

The additive formula applied here follows the standard industry definition confirmed by MABTS Educational Resources: linear inches equal the sum of all three exterior dimensions of an item. This methodology aligns with published size policies from the Transportation Security Administration and all major domestic and international airline carriers. Measurement must include all protruding parts — wheels, handles, and pockets — to match how airlines physically gauge bags at check-in counters.

Reference

Frequently asked questions

What are linear inches and how are they calculated?

Linear inches are the total sum of an object's three dimensions: length plus width plus height. For example, a suitcase measuring 28 × 20 × 12 inches equals 60 linear inches. The formula is purely additive — no multiplication — making it a fast way for airlines and shippers to assess whether an item meets published size restrictions without calculating full volumetric size.

What is the standard airline size limit in linear inches for checked baggage?

Most major U.S. airlines, including American Airlines, Delta, United, and Southwest, set a 62 linear inch (158 cm) limit for standard checked luggage. Bags exceeding this threshold are classified as oversized and incur fees typically ranging from $100 to $200 each way, applied on top of any standard baggage fee. Premium and business fares on some international carriers may allow slightly larger items, so always confirm the policy with the specific airline before travel.

How do you measure linear inches for a suitcase, including wheels and handles?

Measure each of the three exterior dimensions at their absolute widest point, including all protruding parts. For a rolling suitcase, height must include the extended or recessed handle mechanism, and length must account for wheel housings. Add all three resulting numbers together to get total linear inches. Airlines measure at the widest points during check-in, so measuring with all features accounted for gives the most accurate estimate and prevents unexpected fees.

What fees apply if luggage exceeds 62 linear inches?

When checked baggage exceeds 62 linear inches, airlines classify it as oversized and apply additional fees. At most major U.S. carriers, oversized fees range from $100 to $200 per flight segment, charged on top of any standard checked baggage fee. Items exceeding 80 to 115 linear inches — the exact threshold varies by airline — may be refused entirely as checked baggage and must be shipped through a separate cargo freight service at significantly higher cost.

How do you convert centimeter bag dimensions to linear inches?

Divide each centimeter dimension by 2.54 to get its equivalent in inches, then add the three converted values together. For example, a bag measuring 72 cm × 51 cm × 29 cm converts to approximately 28.3 + 20.1 + 11.4 = 59.8 linear inches, safely under the 62-inch limit. The standard 62-inch airline threshold equals exactly 157.48 centimeters, which most international carriers round up to 158 cm in their published baggage policies.

Are linear inches the same as linear feet or linear footage?

Linear inches and linear feet both measure along a straight line, with 12 linear inches equaling 1 linear foot. However, in the context of baggage and package sizing, the term linear inches specifically means the combined sum of all three dimensions (L + W + H), not a single side. By contrast, linear footage in construction, lumber, or archival library contexts refers to a single straight-line length measurement, not an additive total of three dimensions.