radiocarbon.com

Choose a radiocarbon dating laboratory by matching three things to your project: the dating method (AMS vs. radiometric), the turnaround time you can accept, and the sample types the lab will pretreat and run. SGS Beta Carbon Dating Service, for example, states that it provides AMS dating results in 3–14 business days and also offers stable isotope analysis — a useful benchmark when you compare other labs. Before you ship anything, confirm the lab accepts your material, ask what pretreatment is included, and check the published closure schedule, because holiday shutdowns can add weeks to your result date.

Compare labs on the dimensions that change your result

Method, turnaround, and sample size are linked. AMS (accelerator mass spectrometry) counts carbon-14 atoms directly and needs far less material than radiometric dating, which counts decay events over a longer period. If your sample is small, precious, or you need an answer quickly, AMS is usually the deciding factor. If you have a large, robust sample and no deadline pressure, radiometric counting may be offered as an alternative — but confirm the lab still runs it, since many facilities have consolidated onto AMS.

Check accepted sample types and pretreatment

Labs publish the materials they routinely handle. The SGS Beta page lists technical support for selecting suitable samples and names Bones & Teeth, Shell & other Carbonates, Plants & Seeds, and Wood among its categories. Use that list as a checklist against your own material:

• Bone and teeth — usually need collagen extraction; ask whether the lab reports collagen yield, since low yield signals a unreliable date.
• Shell and other carbonates — sensitive to recrystallization; ask about acid pretreatment and whether the lab checks for secondary carbonate.
• Plants, seeds, and charcoal — often the cleanest material; confirm whether the lab picks out rootlets or other intrusions.
• Wood — ask whether the lab can date a single growth ring or must run a bulk sample, since that affects precision.

If your material is not on the lab's published list, email a description and photo before shipping. A lab that has not pretreated your sample type before may still accept it, but you want that confirmed in writing.

Understand what drives the price before you request a quote

Pricing is quoted per project, not published as a flat rate on the page reviewed here. The factors that typically move a quote:

1. Number of samples — per-sample cost usually drops with batch size.
2. Pretreatment — collagen extraction, carbonate leaching, or specific chemical washes are often billed separately from the measurement.
3. Rush service — expedited turnaround carries a premium.
4. Re-runs — if a sample fails or is contaminated, you may pay again; ask about the lab's policy.

Request a written quote that itemizes measurement, pretreatment, and any rush fee, and ask what happens if the sample yields no result.

Prepare and label samples to avoid rejection

Most bad outcomes trace back to contamination or mislabeling, not to the measurement itself.

• Do not touch the sample with bare hands; skin oils add modern carbon.
• Use clean packaging — foil, glass, or lab-supplied vials. Avoid paper and cotton, which can transfer carbon.
• Label inside and outside the container with a unique ID, and keep a matching list of what each ID is, where it came from, and its depth/context.
• Dry samples if the lab requests it, and note any preservative or treatment already applied.
• Ship with the lab's required forms so the sample is logged on arrival.

Confirm reporting and schedule before you ship

Ask what the final report includes: the conventional radiocarbon age, the calibrated date range, the delta-13C value, and the error margin. Calibration matters because the raw radiocarbon age must be converted to a calendar date using a calibration curve, and the curve you use depends on the material and region.

Then check the calendar. The SGS Beta page publishes a 2026 closure schedule: November 19, November 26–27 (Thanksgiving), and December 24, 2026 through January 1, 2027 inclusive for Christmas and New Year. If your deadline falls near those dates, either ship well ahead or confirm the lab's cutoff for samples received before the closure. A sample that arrives the day before a shutdown may not be logged until the lab reopens, adding the full closure period to your turnaround.

A practical submission sequence

1. Identify your sample material and estimate its size.
2. Shortlist two or three labs that accept that material and offer AMS.
3. Request quotes with pretreatment and rush options itemized.
4. Compare turnaround against your deadline, including published closures.
5. Confirm reporting format and calibration.
6. Package, label, and ship with the required forms.
7. Track receipt and confirm the expected result date in writing.

If a lab cannot confirm pretreatment for your material, cannot give a written turnaround, or will not state what the report contains, that is a reason to look elsewhere — regardless of price.

Radiocarbon dating estimates the age of once-living material by measuring how much carbon-14 remains in a sample. It works because living things constantly absorb carbon from the atmosphere, and that intake stops at death, after which carbon-14 decays at a known rate. It applies to organic remains and some carbonates up to roughly 50,000 years old, and the practical accuracy depends heavily on sample type, sample size, and freedom from contamination. If your material is organic or carbonate-based and falls within that age range, radiocarbon dating is likely applicable; if it is older, inorganic (non-carbonate), or heavily contaminated, it is not.

The core mechanism: carbon-14 formation, uptake, and decay

Carbon-14 is produced in the upper atmosphere when cosmic rays interact with nitrogen. The resulting carbon-14 combines with oxygen to form carbon dioxide, which mixes into the atmosphere and enters the food chain through photosynthesis and feeding.

While an organism is alive, its carbon-14 level stays roughly in equilibrium with the atmosphere. When it dies, uptake stops and the carbon-14 already present begins to decay into nitrogen-14 at a fixed rate.

Half-life and the dating window

• Half-life: about 5,730 years. After one half-life, half the original carbon-14 remains; after two, a quarter; and so on.
• Practical limit: roughly 50,000 years. Beyond about 10 half-lives, too little carbon-14 remains to measure reliably, which is why radiocarbon dating cannot reach into the millions of years that other methods (such as potassium-argon) cover.

Because the decay rate is constant, measuring the remaining carbon-14 relative to stable carbon tells you how long decay has been running — that is, how long ago the organism died.

How the measurement is done: AMS vs. traditional methods

Two broad approaches exist, and they differ mainly in sensitivity and sample size.

AMS is more commonly used today because it can date much smaller samples and generally returns results faster. SGS Beta, for example, describes providing AMS dating results in 3–14 business days, which reflects the speed advantage of direct atom counting over waiting for decay events.

What samples can be dated

Radiocarbon dating applies to material that once exchanged carbon with the environment. Based on the laboratory's listed sample categories, common types include:

• Bones & teeth — datable via the organic (collagen) fraction
• Shell & other carbonates — datable because carbonate incorporates environmental carbon
• Plants & seeds — direct products of photosynthesis
• Wood — a classic and often reliable sample type

The key requirement is that the carbon in the sample is original to the organism and has not been replaced or contaminated since death.

Limits, calibration, and common pitfalls

Radiocarbon dating is not a simple "read the number" process. Several factors affect the result:

• Calibration: Atmospheric carbon-14 levels have varied over time, so raw "radiocarbon years" must be converted to calendar years using a calibration curve. An uncalibrated date is not a calendar date.
• Contamination: Even small amounts of younger or older carbon can shift results. Handling, storage, and pretreatment matter, which is why laboratories apply sample-specific preparation.
• Sample size: Traditional methods need larger samples; AMS reduces this requirement but does not eliminate it.
• Age ceiling: Samples near or beyond ~50,000 years yield "beyond limit" results rather than a precise age.
• Material suitability: Non-carbonate inorganic materials and samples with no original carbon cannot be dated by this method.

Deciding whether it fits your sample

Use these conditions to judge applicability:

• Yes, likely suitable: organic material (bone, tooth, shell, plant, seed, wood) with intact original carbon, within ~50,000 years, and enough material for the chosen method.
• No, not suitable: material older than the dating limit, non-carbonate inorganic material, or samples so contaminated that original carbon cannot be isolated.

If your sample is small or valuable, AMS is generally the better fit. If you are unsure, a laboratory's technical support can help match the sample to the right preparation and method — SGS Beta explicitly offers expert technical support for selecting the most suitable samples.

Carbon dating, also called radiocarbon dating, estimates the age of once-living material by measuring how much carbon-14 remains in a sample. It works because living things continually take in carbon from their environment, including a small amount of radioactive carbon-14, and that intake stops when they die. From that point, the carbon-14 decays at a known rate, so the remaining amount acts as a clock. The method is most useful for organic materials and carbonates up to roughly 50,000 years old, and modern labs typically measure the carbon-14 using accelerator mass spectrometry (AMS).

The Principle Behind Carbon Dating

Carbon-14 is created in the upper atmosphere and cycles into plants through photosynthesis and into animals through the food chain. While an organism is alive, its carbon-14 level stays roughly in balance with the atmosphere. When it dies, no new carbon-14 is added, and the existing carbon-14 begins to decay into nitrogen-14.

The decay is steady and measurable: carbon-14 has a half-life of about 5,730 years. That means after one half-life, half of the original carbon-14 remains; after two, a quarter remains, and so on. A lab measures the ratio of remaining carbon-14 to stable carbon and calculates an estimated age from that ratio.

From Measurement to Age Estimate

The calculation is not a simple raw count. Labs calibrate radiocarbon results against known reference records, such as tree rings and other independently dated materials, to convert the measured carbon-14 into a calendar-age estimate. This is why a reported radiocarbon age and a calibrated calendar age can differ.

What Samples Can Be Dated

Radiocarbon dating applies to materials that once exchanged carbon with the environment. According to the SGS Beta Carbon Dating Service, common sample categories include:

The lab notes that expert technical support helps clients analyze the most suitable samples, which matters because sample type, preservation, and contamination all affect whether a reliable date can be produced.

How AMS Dating Fits In

Accelerator mass spectrometry (AMS) is a common modern technique for measuring radiocarbon. Instead of waiting for radioactive decay events to accumulate, AMS counts carbon-14 atoms directly. This generally allows smaller samples to be dated than older decay-counting methods, and it is the approach many radiocarbon laboratories use for routine work.

SGS Beta states that it provides AMS dating results in 3–14 business days, which gives a sense of the turnaround a client can expect from a commercial lab.

Practical Age Range and Limitations

Carbon dating has boundaries worth knowing before submitting a sample:

• Upper limit: Because carbon-14 decays away, samples older than roughly 50,000 years generally retain too little for a reliable measurement.
• Contamination: Added or removed carbon from the environment can shift results, so sample selection and pretreatment matter.
• Material type: Only materials that once took in carbon can be dated this way; rocks and minerals that never incorporated carbon-14 are not suitable.
• Calibration: Raw radiocarbon measurements are converted to calendar ages using calibration curves, so the reported age depends on that step.

Planning Around Lab Schedules

If you are preparing to submit samples, it helps to check a lab's operating calendar. SGS Beta publishes a 2026 holiday and lab closure schedule, including closures around November 19, November 26–27 (Thanksgiving), and December 24, 2026 through January 1, 2027 for Christmas and New Year. Factoring these dates in can prevent unexpected delays in turnaround.

For anyone trying to understand an archaeological, geological, or forensic timeline, carbon dating remains a core tool: it turns the steady decay of carbon-14 into a measurable estimate of age for bones, teeth, shells, plants, seeds, and wood.

AMS dating (accelerator mass spectrometry dating) is a radiocarbon method that counts individual carbon-14 atoms rather than waiting for them to decay. The practical result: it needs milligrams of sample instead of grams, which makes it the default choice for small, rare, or valuable materials. It suits bone, teeth, shell, plant, seed, wood, and charcoal — but only when the sample still contains enough original carbon and hasn't been contaminated. SGS Beta, the lab behind radiocarbon.com, reports AMS results in 3–14 business days.

How AMS dating measures carbon-14

Both AMS and conventional radiocarbon dating rely on the same principle: living things absorb carbon-14 while alive, and that carbon-14 decays at a known rate after death. The difference is how the remaining carbon-14 is measured.

• Conventional radiocarbon dating detects the radiation released as carbon-14 atoms decay. Because decays are infrequent, the method needs a relatively large sample and long counting times to get a statistically usable signal.
• AMS dating uses an accelerator mass spectrometer to separate and count carbon-14 atoms directly. It measures atoms, not decay events, so far fewer atoms are needed for a result.

That single change — counting atoms instead of waiting for decays — is what drives nearly every practical advantage of AMS.

Why AMS needs far smaller samples

Because AMS counts atoms directly, the sample size drops from grams to milligrams. This matters in three common situations:

1. The sample is small or precious. A single seed, a fragment of bone, a sliver of wood, or a few shell fragments may be all that survives. Conventional dating could consume or require more material than exists.
2. The sample is rare or museum-held. When you cannot sacrifice a large piece, AMS lets you date a small subsample.
3. You need to isolate a specific fraction. Small samples make it feasible to target a particular component (for example, a specific organic fraction) rather than dating bulk material.

The trade-off is that smaller samples are more sensitive to contamination. A tiny amount of modern carbon — from handling, storage, or the burial environment — can shift an AMS result more than it would a large conventional sample. Clean collection and honest disclosure of how a sample was stored are part of getting a reliable date.

Sample types commonly dated by AMS

SGS Beta lists technical support for selecting the most suitable samples and names several categories:

The lab's guidance is to analyze the most suitable samples with expert technical support — meaning the right pretreatment and fraction choice depends on the material, not just its size.

Turnaround time and precision expectations

SGS Beta states AMS dating results are delivered in 3–14 business days. Precision depends on the sample, its carbon content, and how clean it is; AMS itself does not guarantee a tighter date than conventional dating — it mainly reduces the sample size required. Plan around the lab's closure schedule if your deadline is tight: the posted 2026 closures include November 19, November 26–27 (Thanksgiving), and December 24, 2026 through January 1, 2027 (all dates inclusive) for Christmas and New Year.

Key limits and pitfalls

• Contamination. Small AMS samples are more vulnerable to introduced modern or old carbon. How a sample was collected, handled, and stored affects the result.
• Calibration. A measured radiocarbon age is not a calendar date. It must be calibrated, and the calibration you use affects the final range.
• Material-dependent pretreatment. Bone, shell, plant, wood, and charcoal each need different treatment; the wrong fraction can produce a misleading date.
• Not everything can be dated. Material without sufficient original carbon, or that has exchanged carbon with the environment, may not yield a meaningful result.

Choosing between AMS and conventional dating

Choose AMS when the sample is small, rare, valuable, or when you need to isolate a specific fraction. Choose conventional radiocarbon dating when you have ample material and the larger sample size is not a constraint — it can be the more economical route for bulk material. If you are unsure, the deciding questions are: how much material can you spare, and how confident are you that it is uncontaminated? Those two answers usually settle the method.