How big is a half-dollar coin? The distinctive silver half-dollar coin has been minted in the United States for over 200 years. If you’ve ever wondered about the size of this iconic coin, you’ve come to the right place.
If you’re short on time, here’s a quick answer: a half-dollar coin has a diameter of 1.205 inches (30.61 mm) and a thickness of 0.085 inches (2.15 mm).
In this comprehensive guide, we will explore everything you need to know about the dimensions of a half dollar, from its diameter and thickness to comparisons with other coins. You’ll come away with a complete understanding of just how big a half-dollar truly is.
The Diameter Measurement of a Half Dollar
Defining the Diameter
The diameter of a coin refers to the length of a straight line passing through the center of the coin from one edge to the opposite edge. For a circular coin like the half dollar, this measurement captures the overall size of the coin.
Specifically, the diameter of a standard circulated half-dollar coin in the United States measures 30.61 mm or 1.205 inches. This size has been maintained by the U.S. Mint with only the most minor variations since the coin was first minted in 1794.
Diameter Compared to Other Coins
To understand the size of a half dollar, it helps to compare its diameter measurement against other common U.S. coins:
- Penny – 19 mm diameter
- Nickel – 21.21 mm diameter
- Dime – 17.91 mm diameter
- Quarter – 24.26 mm diameter
As the table shows, the half-dollar is much larger than a dime or penny but slightly smaller than a quarter. The size and thickness of the half dollar make it easy to identify by touch alone for the visually impaired or when low light conditions obscure visual identification.
The diameter has been kept consistent by the U.S. Mint to ensure vending machines and other coin-operated devices designed to accept half dollars do not need reconfiguration. This allows for an efficient flow of currency.
Thickness of the Half Dollar
Specifications for Thickness
The current half-dollar coin has a thickness of 0.085 inches (2.15 mm), as specified by the United States Mint. This has been the standard thickness since 1965 when the coin switched from being made of 90% silver to being made from a copper-nickel-clad material.
Before 1965, the half dollar had a thickness of 0.085 inches as well when it was minted from 90% silver. The thickness has remained consistent even as the composition changed to help the coin work properly in vending machines and coin acceptance systems that were designed for the original silver versions.
How Thickness Compares
Compared to other United States coin denominations, the half dollar is slightly thicker than the nickel (0.083 inches) but slightly thinner than the dollar coin (0.118 inches). The dime, quarter, and penny coins are all substantially thinner, at just 0.053 inches, 0.069 inches, and 0.055 inches respectively.
The increased thickness of the half dollar allows it to be minted with the “reeding” on the coin’s edge – the ridged border on the side. This helps prevent counterfeiting and “shaving” bits of metal off the coin’s edge. It also gives the coin a distinctive feel and appearance.
| Coin Denomination | Thickness |
| Penny | 0.055 inches |
| Nickel | 0.083 inches |
| Half Dollar | 0.085 inches |
| Dollar Coin | 0.118 inches |
So while the half dollar is by no means the thickest coin, its thickness is carefully calibrated both for practical purposes like vending machines as well as security and aesthetic purposes.
Other Key Measurements
Weight in Grams
A United States half-dollar coin weighs 11.34 grams. This has been the standard weight since 1965 when the composition changed from 90% silver and 10% copper to a copper nickel-clad coin with outer layers of 75% copper and 25% nickel surrounding an inner core of pure copper.
The change in composition was done for economic reasons as the value of the silver in the coins was exceeding the face value of the coin. By changing to a cheaper metal composition, the US Mint could produce half-dollar coins without losing money on each one minted.
Total Surface Area
The total surface area of a United States half-dollar coin is approximately 24.26 cm2. This is calculated based on the diameter and thickness measurements:
- Diameter: 30.61 mm or 1.205 inches
- Thickness: 2.15 mm or 0.085 inches
Using these measurements, we can calculate the total surface area as the area of the two circular faces plus the area along the rim/edge of the coin.
Total Surface Area
736.04 + 736.04 + 199.57 = 24.26 cm2
| Surface | Area Equation | Calculation |
| Face #1 | A = π r2 | A = π (15.305 mm)2 = π x 234.25 mm2 = 736.04 mm2 |
| Face #2 | A = π r2 | A = π (15.305 mm)2 = π x 234.25 mm2 = 736.04 mm2 |
| Edge/Rim | A = 2πrh | A = 2π (15.305 mm) x (2.15 mm) = 199.57 mm2 |
As the math shows, the majority of a half-dollar coin’s surface area comes from its two circular faces. But the edge/rim also contributes a non-trivial amount at over 8% of the total.
These surface area calculations can be useful for understanding how much space is available for minting and design elements on the coin’s faces and rim.
The Half Dollar Over Time
Original Coin Design
The very first Half Dollar coin was minted in 1794. It featured a bust of Lady Liberty on the front wearing a cap symbolizing freedom. The reverse side depicted an eagle surrounded by laurels, which represented victory and honor.
This classic design set the precedent for many US coin designs to follow.
The Half-Dollar has always been made of 90% silver and 10% copper, giving it an attractive shine and jingle. At 30.6 mm in diameter and 2.15 mm thick, the coin has a substantial feel and made a ringing sound when dropped.
Changes Through the Years
While the basic image of Lady Liberty remained on the obverse until 1947, the reverse designs went through several changes over the years. Some notable variants include the Flowing Hair type from 1794-1795, the Draped Bust type from 1796-1807, and the Seated Liberty type from 1839-1891.
In the early 1960s, increased silver prices led to widespread hoarding and melting of silver coins. To address this, Congress ordered the mint to remove silver from circulating coinage like the half-dollar.
The most recent redesign came in 1971 when the Half Dollar switched to a depiction of Independence Hall in Philadelphia on the reverse. The obverse was changed to a portrait of President John F. Kennedy after his assassination in 1963. This design is still used today, over 50 years later.
How Big Is A Half-Dollar Coin – Conclusion
With a diameter of 1.205 inches and a thickness of 0.085 inches, the half dollar has dimensions on par with other United States coin denominations. Understanding the size of a half dollar gives you an appreciation for this historic coin that has been in circulation for over 200 years.
The next time you get a half dollar in change, take a closer look and admire its distinctive dimensions. A half dollar’s large size sets it apart from other coins – proof of the enduring legacy of this unique denomination.
