Carbon-14 has a half-life of 5,730 ± 40 years—, half the amount of the radioisotope present at any given time will undergo spontaneous disintegration during the succeeding 5,730 years.Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.The precision of a radiocarbon date tells how narrow the range of dates is.There are two main factors which determine the precision of a radiocarbon date.Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food.Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.

Because the radiocarbon to stable carbon ratio in the atmosphere has fluctuated over time, there are "wiggles" in the calibration curve.In Accelerator Mass Spectrometry (AMS), for example, the number of radiocarbon atoms in a stream of atoms coming from the sample is counted.Thus there are statistical counting uncertainties proportional to the square root of the number of atoms counted.In field bleaching, the woven cloth was soaked in hot lye solution, washed, soaked in sour milk and washed again.For example, two samples taken from the tombs of two Egyptian kings, Zoser and Sneferuindependently dated to BC plus or minus 75 years, were dated by radiocarbon example carbon dating errors to an average of BC plus or minus years.