The most current US penny or one cent coin is known as the Union Shield and weighs approximately 2.5 grams or 0.088 ounces.
It is 19.05 mm or 0.75 inches in diameter, 1.52 mm thick, and is made from a Copper Plated Zinc composition which includes 97.5% Zinc and 2.5% Copper.
Image Source: USA Coinbook
There are 50 of these US pennies in a roll which weighs approximately 125 grams or 4.4 ounces and equates to a value of $0.50.
The US one cent piece or penny has changed weight and size many times over the years since it was first produced in 1787 in the form of the Fugio Cent.
The Fugio weighed in at a hefty 10.2 grams (0.36 ounces) and was made from solid copper.
There were other prototype cents around between 1787 and 1793, namely the 1792 Birch Cent and Silver Center.
However the first large US penny to be officially produced by the United States Mint in 1793 was known as the Flowing Hair Chain.
These early coins were also weighed in Grains so I've included that weight measurement alongside the Grams and Ounces.
The first large cents produced in the United States were made from 13.48 grams of pure copper.
Between the years 1793 and 1795 the large cent design changed numerous times.
The first coins were designed by Henry Voigt and were known as the Flowing Hair Chain and Flowing Hair Wreath.
These initial large US pennies were quickly superseded by the Liberty Cap designed by Joseph Wright which was also 13.48 grams of pure copper.
Image Source: USA Coinbook
Image Source: USA Coinbook
During the period between 1796 and 1857, the large United States cent dropped in weight from 13.48 grams to 10.89 grams.
There were four main design changes during this time period, however the coin was still stuck from 100% Copper.
The first new design by Robert Scot was minted between 1796 and 1807 and was called the Draped Bust.
In 1804 another design was implemented by John Reich called the Classic Head which lasted until 1814.
1816 saw another new design by Robert Scot in the form of the Coronet Large Cent.
This new design of Coronet was called the Matron Head and lasted until 1839.
From 1839 to 1857, the last design for an US large cent was created by Christian Gobrecht and was named the Braided Hair.
Image Source: USA Coinbook
Image Source: USA Coinbook
Image Source: USA Coinbook
Image Source: USA Coinbook
In 1856 the US Mint started to produce small cents measuring approximately 19mm as opposed to previous penny size of 28mm.
The weight and metal composition of the coin also changed quite significantly during this production period.
The small US penny now weighs 4.67 grams and is made from 88% Copper and 12% Nickel.
The designer for these new coins which were struck between 1856 and 1864 was James B Longacre.
The first coin was known as the Flying Eagle and the second was known as the Indian Head.
Image Source: USA Coinbook
Image Source: USA Coinbook
From 1864 onwards it was decided that the metal composition of the Indian Head was going to be changed to Bronze which is 95% Copper, 5% Tin and Zinc.
The design didn't change much, however the weight changed to 3.11 grams.
1864 actually produced one of the most valuable Indian Head cents of all time.
It was a proof version of the 1864 penny known as the 'L on Ribbon' variety.
This highly sought after coin sold at auction on 13th October 2011 for $161,000.
In 1909 the Indian Head was phased out and the Lincoln Wheat was first struck.
Similar in weight and metal composition to its predecessor, this new penny was designed by Victor D Brenner.
Image Source: Courtesy of Heritage Auctions
Image Source: Courtesy of Heritage Auctions
The metal composition and weight of the Lincoln Wheat cent changed briefly in 1943 due to World War II.
All available copper was needed to make ammunition for the ongoing war and it was decided to make the 1943 penny from zinc coated steel.
It weighed a few grams less at 2.7g and the change in the minting process caused one of the most valuable wheat penny error coins ever to be produced.
Image Source: USA Coinbook
Between 1944 and 1946, shell-case pennies as they were known, were made from Brass.
The design didn't change and they still weighed the same except they didn't contain any Tin.
Image Source: USA Coinbook
Between 1947 and 1958 the Lincoln penny was back to its original metal compostion of Bronze.
In 1959 a new design was released by the United States mint called the Lincoln Memorial.
The new coin was designed by Frank Gasparro and featured an image of the Lincoln Memorial on the reverse.
The current weight of 3.11 grams didn't change.
Image Source: USA Coinbook
Image Source: USA Coinbook
In 1962 the United States one cent coin returned to being made from Brass as opposed to Bronze.
The weight remained at 3.11 grams, however the Tin was removed from the metal composition.
Image Source: USA Coinbook
1982 saw the first major change to the Lincoln penny since Frank Gasparro redesigned it in 1959.
The metal composition changed to 97.5% Zinc and 2.5% Copper and the weight also changed to 2.5 grams.
This is the lightest the one penny coin has ever been since it was first produced in 1793.
Image Source: USA Coinbook
The 2009 one cent piece was a special strike specifically for that year to celebrate the bicentennial of Abraham Lincoln.
Four different designs were created in 2009 by four different designers to commemorate his 200th birthday.
The first reverse featuring a log cabin in Kentucky was designed by Richard Masters and sculpted by Jim Licaretz celebrating the former president's birthplace and early childhood.
The formative years in Indiana reverse face was designed and sculpted by Charles Vickers.
It depicts a young Lincoln taking a break from rail splitting and reading a book.
The next design by Joel Iskowitz, sculpted by Don Everhart, is titled, 'Professional life in Illinois' and depicts Lincoln standing before the Springfield Illinois State Capitol as a young lawyer.
The fourth reverse design was created by Susan Gamble and sculpted by Joseph Menna.
It depicts a half completed dome from the US Capitol building.
This last design was to signify Lincoln's presidency in Washington DC.
The proof and satin finish strike of the 2009 Lincoln penny were made from the same Bronze metal composition that was used on the first version of the Lincoln Wheat in 1909.
Image Source: USA Coinbook
The most current design of the of the US penny is the Lincoln Shield and was created by Lyndall Bass.
Image Source: USA Coinbook