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Carbon Dating aka Radiocarbon Dating

One of the dating methods most people think of when they talk about archaeology is radiocarbon dating. This is one of the absolute dating methods that archaeologists use to date an artifact. Only organic materials can be dated using this method, but archaeologists can also use it for inorganic artifacts sometimes too.  If an inorganic artifact, like pottery or stone tools, comes from the same layer of soil as an organic artifact, like plant remains or bone tools, archaeologists can use the age of the organic artifact to assign an approximate age to the inorganic artifacts as well.

Even though radiocarbon dating is a pretty well known technique not all archaeologists that have organic samples are able to do it, or perhaps more importantly, the funds to do it. It can cost over $600 to run these kinds of special scientific tests so sometimes archaeologists need to rely on other dating techniques instead.

The science behind it all…

Where does the carbon come from?
Where does the carbon come from?

All organic materials contain carbon. During its lifetime, a plant or animal aborbs carobon (14C and 12C) from the atmosphere. Once it dies, its radiocarbon clock beings to tick down as the amount of 14C begins to decay into 12C. This happens at a constant rate, known as the half-life. Radiocarbon dating is based on the half-life of carbon isotope 14 (written as 14C) as it undergoes radioactive decay into the carbon isotope 12 (12C), which is stable and does not decay. Physicists can measure the ratio of 14C to 12C and calculate when the organism died.

The half-life of 14C is 5730 years, which means that after 5730 years half of the 14C will have decayed into 12C.  The thing is the process isn’t that exact!

Not as accurate as hoped…

  • “A.D. 550 +/-50”: the real date of this artifact is between A.D. 500 and A.D. 600 because the results of radiocarbon dating are always estimates.
  • We can only date objects up to 100,000 years old this way (But that captures a large span of the human experience!)
  • “A.D. 600 cal”: This shows a calibrated date that scientists have calculated since the ratio of 14C to 12C in the atmosphere is not steady through time
  • Nothing that has died after 1950 can be dated using the radiocarbon method. Nuclear tests in the 1950s and 1960s threw off the natural ratio of carbon isotopes.

How its done…

Radiocarbon dating methods have really improved over the decades.  In the 1940s physicists need really large samples to test radiocarbon—they would use a Geiger counter to literally count the rate of decay and it wasn’t very accurate. But in the 1970s a new method that used a fancy piece of equipment known as an Accelerator Mass Spectrometer (AMS) was discovered.  Radiocarbon tests that use AMS are a lot faster, more accurate, and can date even very tiny samples, even corn kernels!

An accelerator mass spectrometer used for radiocarbon dating.

In addition to radiocarbon dating being expensive and sometimes inaccurate, it also takes time, and most labs have long wait lists. It can be a long time before archaeologists are able to get the results of their tests. Regardless, radiocarbon dating has become a media and movie darling, making it one of the most well known techniques for dating artifacts.

Want to learn more about dating methods?  Be sure to check out the series introduction or follow the links below!

Relative Dating Methods in Ontario Absolute Dating Methods in Ontario
Superposition Radiocarbon
Seriation Dendrochronology
Index Types


Paul Bahn, and Colin Renfrew. Archaeology Theories, Methods, and Practice. 5th ed. London: Thames & Hudson. 2008.


Sisi Yang


Does the museum offer AMS dating service? If yes, could you kindly let me know the price, approximate wait time and process/requirement/form? I recently purchased a wooden bench, and would like to know its age.

Thank you,

Sparky Wilson

Diving in Muskoka i came up with an interesting artifact
Wood handle hand carved
Steel Blade aprox 18″ in length

Its obviously very old

Is it possible to determine its age through your services??

Heather Hatch

Hello Sparky,

Sounds like an interesting find! Unfortunately, we do not offer this service. If you are interested, you can check out the link that Nicole provided above.

Marie Butler

Do you do carbon dating of wood..? If so, my brother found two pieces of shipwreck at Peche Island. One is an old oak rib of a boat with huge square nails sticking out of it, and the other is one of the bottom spines of probably the same boat also with square nails with hand pounded hex heads. We know that the schooner Eugenie wrecked at Peche Island on the American side in 1865. She was a 38 ton schooner. We would like to know how old this wood is. Is it very expensive to have it carbon dated. Please advise
Thank you
Marie Butler

Nicole Aszalos

Hi Marie,

Sounds like an interesting find! Unfortunately, we do not carbon date wood. Cost wise it varies but ranges in multiple hundreds of dollars.

Saskia Wolsak

Hello! A friend in Bermuda had a piece of human femur dated in the late 1970s — he thinks it was through this museum. Do you think that is possible? All he remembers is that he was told it was from a Caucasian male, but he has no record of the date. I am wondering if it’s possible if it was through you and, if so, if you still have those records. I can send further details if necessary. Thank you!

Madison Stirling

Unfortunately, it could not have been tested through us as we do not perform carbon dating here at the Museum of Ontario Archaeology.


Hi there, I have an artifact of an AKAN TERRACOTTA HEAD, would it be possible to have it carbon dated. I could send photos on request. Please let me know asap.

Thank you,


Madison Stirling

Unfortunately, we do not perform carbon dating here at the Museum of Ontario Archaeology.

Travis Martin

I have a stone tool what looks like a small axe that was found was told I should show it to the pro’s so that’s what I look to do !!!!! . I live in Ontario
It Was found miles down river from a old fur trading post if interested In checking this thing out as its the first time I ever seen come across something like this hunting.

Kat MacDonald

Hello Travis,

The best thing to do would be to take some pictures and send them and any information you may have to our email We will see if we are able to help or at least direct you to someone who might be able to.

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