The Babylonians and Sumerians had a system in which there were 60 shekels in a mina and 60 minas in a talent (in Ancient Greece one talent was 26 kg of silver). The Roman talent consisted of 100 libra (pounds) which were smaller in magnitude than the mina.
When used as a measure of money, it refers to a talent-weight of gold or of silver. The gold talent is reported as weighing roughly the same as a person, and so perhaps 50 kg (110 lb avoirdupois). Some authorities say that the talent typically weighed about 33 kg (75 lb) varying from 20 to 40 kg. The international price of gold is about US$600 per troy ounce. One gram costs about $20. At this price, a talent (33 kg) would be worth about $660,000. Similarly, at the 2005 price of about $7.60/troy ounce or 25 cents/gram, a 26 kg silver talent would be worth about $6,500. Thus when we read that King Auletes of Egypt paid Gaius Julius Caesar the sum of 6,000 talents of gold to grant him the status of a "Friend and Ally of the Roman People". This amount was about $3 billion USD. These estimates are only rough values, because they are based on modern estimates.The value of silver in comparison to gold drastically changed. This is because of the output of the Spanish silver mines in the New World. In ancient times the same amount of silver was often worth more than gold. The estimates do not account for the less technical mining ability of the time, nor that there were still native deposits available. Later in Roman history, during the medieval Byzantine period, the emperor Basil II was said to have stockpiled the legendary amount of 200,000 talents of gold, which in modern terms would be worth approximately $100 billion USD. At any rate, he did save enough money that the Byzantine government was able to remit all taxes paid during the final two years of his reign.[source?]
Another way to calculate the modern equivalent to a talent is from its use in estimating military pay. During the Peloponnesian war in Ancient Greece, a talent was the amount of silver needed to pay the crew of a trireme for one month. Hellenistic mercenaries were commonly paid one drachma for every day of service, which was a good salary in the post-Alexander (III) days. 6,000 drachma made a talent. Based on this fact, assuming a crew of roughly 200 rowers paid at the basic pay rate of a junior enlisted member of the US armed forces (E-2), a talent would be worth nearly $300,000.
The talent as a unit of coinage is mentioned in the New Testament in Jesus's parable of the talents, but it is not clear exactly what quantity of money is implied; the important point in the parable is that even one talent was a very large sum.