Why Is Liquor Called A Fifth Origin Bottle Size Explained

In bars, liquor stores, and cocktail conversations, you may have heard someone refer to a bottle of whiskey or vodka as “a fifth.” While today’s standard 750ml bottle dominates shelves worldwide, the term “fifth” persists—steeped in history, regulation, and American drinking culture. But why exactly is liquor called a fifth? The answer lies in early 20th-century measurement standards, Prohibition-era legislation, and the gradual shift from imperial units to metric sizing.

This article explores the origin of the “fifth” as a bottle size, traces its evolution over the past century, and explains how this legacy term remains relevant—even as the industry has officially moved on.

The Historical Meaning of “A Fifth”

The term “fifth” refers to one-fifth of a U.S. gallon. In practical terms, that equals 25.6 fluid ounces or approximately 757 milliliters. Before the widespread adoption of the metric system in the United States, spirits were commonly sold in bottles sized as fractions of a gallon: pints (1/8), quarts (1/4), and fifths (1/5). Among these, the fifth became the most popular for retail liquor sales due to its balance between portability and volume.

By the late 19th century, glass manufacturing advances allowed for standardized bottle production. Distillers began using machine-made bottles calibrated to hold one-fifth of a gallon. This consistency made it easier for retailers, regulators, and consumers to know exactly how much they were purchasing.

“Before metrication, the ‘fifth’ was the gold standard for consumer liquor bottles in America—it offered enough for several drinks without being unwieldy.” — Dr. Rebecca Langston, Historian of American Alcohol Policy

Prohibition and the Standardization of the Fifth

The term gained official traction during Prohibition (1920–1933), not because people were legally buying liquor, but because when the ban was lifted, the federal government needed a way to regulate alcohol sales efficiently. With the repeal of the 18th Amendment and the passage of the 21st Amendment, states and the federal Alcohol Administration Act established clear rules for labeling and bottling.

In 1935, the U.S. Bureau of Alcohol, Tobacco and Firearms (ATF) formally recognized the “fifth” as the standard size for distilled spirits. It wasn’t just a colloquial term anymore—it was codified into law. Bottles labeled as containing “one-fifth of a gallon” had to meet strict tolerances, ensuring fair trade practices and consistent taxation.

This standardization helped rebuild public trust in legal alcohol after years of bootlegging and inconsistent quality. Consumers knew that if they bought a “fifth,” they were getting a reliable amount of product.

The Shift to Metric: How 750ml Replaced the Fifth

Despite its deep roots, the fifth began to fade from official use in the 1970s. As part of a broader international push toward metrication, the U.S. alcohol industry adopted metric measurements to align with global markets. In 1979, the ATF mandated that all distilled spirits be sold in metric sizes.

The closest metric equivalent to a fifth (757 ml) is 750 ml. Though slightly smaller—by about 7 milliliters—the 750ml bottle was close enough to maintain consumer familiarity while simplifying export logistics and production. Over time, manufacturers phased out the old 757ml bottles, and the 750ml format became universal.

Interestingly, the difference of 7ml—less than two tablespoons—was negligible for most drinkers. But for producers, it meant more bottles per batch and slight cost savings over millions of units.

Tip: When reading vintage cocktail recipes, assume “a fifth” means roughly 750ml unless otherwise specified by era.

Why We Still Say “A Fifth” Today

Even though the actual fifth-sized bottle no longer exists, the term endures in American vernacular. Language often lags behind technological or regulatory change, especially when tied to cultural habits. Calling a 750ml bottle “a fifth” is similar to referring to any facial tissue as a “Kleenex”—a brand or unit becomes synonymous with the category.

Older generations continue to use the term, and younger drinkers pick it up through music, film, and regional speech. Phrases like “I’ll bring a fifth to the party” remain common, even if the speaker doesn’t know the historical context.

Moreover, some craft distillers and heritage brands intentionally evoke nostalgia by referencing “the old fifth” in marketing copy, reinforcing the romanticized image of mid-century American drinking culture.

Common Liquor Bottle Sizes Compared

To understand where the fifth fits historically and practically, here’s a comparison of standard liquor bottle sizes used in the U.S. today:

Name	Volume (oz)	Volume (ml)	Notes
Mini / Nip	1.7 oz	50 ml	Airplane bottles or sampler sizes
Pony	3.4 oz	100 ml	Double mini; sometimes used in cocktails
Pint	12.7 oz	375 ml	Half of a fifth; popular for budget purchases
Fifth / Standard	25.4 oz	750 ml	Modern replacement for the original fifth
Liter	33.8 oz	1000 ml	Larger format, often better value per ounce
Magnum	50.8 oz	1500 ml	Double a fifth; popular for parties or gifting

Step-by-Step: How the Fifth Evolved Into the 750ml Bottle

1. Late 1800s: Glass bottles become mass-produced; distillers adopt “one-fifth of a gallon” as a standard retail size.
2. 1935: U.S. government formalizes the fifth as the standard liquor bottle after Prohibition ends.
3. 1950s–1960s: The fifth dominates American liquor sales; it’s the go-to size for home bars and gifts.
4. 1970s: Global pressure for metric standardization grows; U.S. industries begin planning the transition.
5. 1979: ATF mandates metric-only labeling; 750ml becomes the new legal standard, replacing the 757ml fifth.
6. 1980s–Present: The term “fifth” survives colloquially, while 750ml bottles become universal in stores.

Real Example: The Last Legal Fifth

In 1978, a small distillery in Kentucky prepared what would become one of the last legally bottled fifths. Eagle Creek Spirits, known for its bourbon, filled thousands of 757ml bottles marked “1/5 gal” before the 1979 deadline. Customers noticed the subtle difference when newer bottles arrived in 750ml—some complained of “getting less for the same price,” though the visual difference was nearly imperceptible.

The company responded with a print ad campaign stating: “Same great taste. Same familiar size. Now in metric.” Within a few years, even longtime customers stopped noticing the change. The transition succeeded because the cultural concept of “a fifth” remained intact—even as the physical contents shifted slightly.

Frequently Asked Questions

Is a fifth of liquor still exactly one-fifth of a gallon?

No. A true fifth is 757 milliliters (one-fifth of a U.S. gallon), but modern liquor bottles are 750ml. The 7ml difference is due to the shift to metric standards in 1979.

Why didn’t the U.S. keep the exact fifth size?

The move to metric was driven by international trade needs. Using round metric numbers like 750ml simplified exports, labeling, and compliance across countries. The minor volume reduction was accepted as a trade-off for standardization.

Can I still buy a real fifth of liquor?

Not legally in the U.S. All commercially sold distilled spirits must adhere to approved metric sizes. However, some commemorative or imported bottles may reference “the original fifth” for nostalgic appeal.

Practical Tips for Understanding Bottle Sizes

• When shopping, remember that “a fifth” means 750ml today—even if older relatives call it something different.
• Compare price per ounce or per milliliter to get the best value—larger bottles often offer savings.
• If you're mixing cocktails from vintage recipes, assume a “fifth” refers to ~750ml unless the recipe specifies otherwise.
• Collectors should note that pre-1980 bottles labeled “1/5 gal” are authentic fifths and may have historical value.

Tip: Always check the ml marking on the label—this is the most accurate measure, regardless of slang terms used.

Conclusion: Raising a Glass to the Fifth

The story of the fifth is more than a footnote in alcohol history—it reflects broader changes in regulation, globalization, and language. Though the original 757ml bottle has disappeared from store shelves, the term lives on as a cultural artifact, connecting today’s drinkers to decades of American tradition.

Understanding why liquor is called a fifth adds depth to every pour. Whether you're stocking a home bar, interpreting an old cocktail recipe, or simply curious about the origins of everyday terms, knowing this piece of history enriches your appreciation of the drink—and the language we use to describe it.

💬 Did you grow up hearing “a fifth” in your household? Share your memories or regional expressions in the comments below!