Another characteristic of carbon 14 is that it is continually being formed in the upper atmosphere as a product of the reaction between neutrons produced by cosmic rays and nitrogen atoms.
These carbon 14 atoms then instantaneously react with oxygen present in the atmosphere to form carbon dioxide.
The assumptions, however, do not paint the real picture.
There are several factors that need to be considered because they affect the global concentration of carbon 14 and therefore that of any given sample for radiocarbon dating.
Three isotopes of carbon are found in nature; carbon-12, carbon-13 and carbon-14.
Carbon-12 accounts for ~99.8 % of all carbon atoms, carbon-13 accounts for ~1% of carbon atoms while ~1 in every 1 billion carbon atoms is carbon-14.
Because the date is only the conventional age, you need to transform it to calendar years by using a calibration program.The basis of radiocarbon dating includes the assumption that there is a constant level of carbon 14 in the atmosphere and therefore in all living organisms through equilibrium.