"The KJV rendering of the Greek lepton, the smallest coin in circulation, a tiny bronze piece. Mark 12:42 gives the exchange rate inside the verse: two mites make a farthing (kodrantes, the Roman quadrans). Modern translations say two small copper coins; Luther coined the German word Scherflein for it."

"How much was a penny in the KJV?"

"The KJV penny is the Greek denarion, the Roman denarius: a silver coin equal to a laborer's full day wage (Matthew 20:2). Reading it as a modern penny inverts several parables; 200 pennies (Mark 6:37) is some eight months of wages, not pocket change."

"How much were the thirty pieces of silver?"

"Thirty silver shekels, in the first century most likely Tyrian tetradrachms, each worth about four denarii: roughly 120 days' wages. Exodus 21:32 fixes thirty shekels as the compensation price for a slave gored by an ox. Zechariah 11:12-13 names the same sum as the insulting price at which the shepherd is valued."

"How much is a talent?"

"Not a coin but a weight of about 34 kilograms of silver, roughly 6,000 denarii: twenty years of wages. The unforgiving servant of Matthew 18 owed 10,000 talents, about 60 million denarii, against the 100 denarii owed to him. The ratio is 600,000 to one, and it is the point of the parable."

"How much are these coins worth today?"

"Convert through the day wage: one denarius equals one day of labor. At an ordinary US laborer's wage of about $150 a day, the widow's two mites are about $2.40, the temple tax about $300, the thirty pieces of silver about $18,000, and the unforgiving servant's ten thousand talents about $9 billion."

Every coin in the New Testament and what your translation calls it

The KJV pays in mites, farthings, and pennies. Modern English Bibles pay in denarii and small copper coins. Luther pays in Scherflein, Groschen, and Silberlinge. Underneath them all sits one set of Greek and Hebrew coins with fixed exchange rates, several of them stated inside the verses themselves. The value that converts across every translation is days of labor, the only exchange rate that survives twenty centuries.

The crosswalk table

Greek/Hebrew	KJV	Modern English (ESV/NIV)	Luther / Elberfelder	Value	Where
λεπτόν lepton	mite	small copper coin	Scherflein	½ quadrans; smallest coin	Mark 12:42 , Luke 21:2
κοδράντης kodrantes (Lat. quadrans)	farthing	penny	Heller / Pfennig	¼ assarion	Matthew 5:26 , Mark 12:42
ἀσσάριον assarion	farthing	penny	Groschen* / Pfennig	1/16 denarius	Matthew 10:29 , Luke 12:6
δηνάριον denarion	penny	denarius	Groschen* / Denar	1 day’s wage	Matthew 20:2 , 22:19 ; Mark 6:37
δραχμή drachme	piece of silver	silver coin	Groschen* / Drachme	≈ 1 denarius	Luke 15:8
δίδραχμον didrachmon	tribute	two-drachma tax	Tempelgroschen / Doppeldrachme	2 denarii; the temple tax	Matthew 17:24
στατήρ stater	piece of money	shekel / four-drachma coin	Silbergroschen / Stater	4 denarii; pays temple tax for two	Matthew 17:27
ἀργύριον argyrion (pl.)	pieces of silver	silver coins	Silberlinge	shekel-class silver	Matthew 26:15
μνᾶ mna	pound	mina	Pfund	≈ 100 denarii	Luke 19:13
τάλαντον talanton	talent	talent	Zentner* / Talent	≈ 6,000 denarii; a weight, not a coin	Matthew 18:24 , 25:15
שֶׁקֶל shekel (OT)	shekel	shekel	Silberling / Sekel	≈ 11 g silver; a weight before a coin	Genesis 23:16 , Exodus 30:13

* Luther’s renderings vary between the 1545, 1912, and 2017 revisions (Groschen covers several different coins in the older editions; the 2017 uses Silbergroschen and Zentner in places). The German column follows common Luther usage and should be checked against the specific edition quoted. The Elberfelder column follows the 1905 edition, the text of elberfeldermatters.com; it uses Pfennig for both kodrantes and assarion.

Two KJV traps in the table:

“Farthing” is two different coins. Matthew 5:26 and Mark 12:42 use kodrantes (quadrans); Matthew 10:29 and Luke 12:6 use assarion, four times bigger. Same English word.
“Penny” is a day’s wage. Every KJV penny is a denarius. The laborers of Matthew 20:2 agree to work sunrise to sunset for a penny because the penny is a full day’s silver.

Exchange rates stated inside the text

The Bible carries its own conversion notes:

Mark 12:42: “two mites, which make a farthing”: 2 lepta = 1 quadrans.
Matthew 20:2: “he had agreed with the labourers for a penny a day”: 1 denarius = 1 day.
Matthew 17:24-27: the temple tax is the didrachmon (2 drachmas ≈ 2 denarii, the half-shekel of Exodus 30:13; its administration fills the Mishnah tractate Shekalim); the coin in the fish’s mouth is a stater (4 drachmas): “that take, and give unto them for me and thee.” The stater pays exactly two men’s tax.

In today’s money

The day wage is the exchange rate that survives; give it a modern number and every coin converts. At a US laborer’s wage of about $150 a day (roughly $18 an hour, a worker’s pay, not a professional salary):

Coin	Fraction of a day wage	In today’s money
lepton, the widow’s mite	1/128	≈ $1.20
kodrantes, the farthing	1/64	≈ $2.40
assarion, the other farthing	1/16	≈ $9.40
denarion, the penny	1	$150
didrachmon, the temple tax	2	$300
stater, the coin in the fish	4	$600
mna, the pound	100	$15,000
talanton, the talent	6,000	$900,000

Adjust the anchor to your own economy; the fractions stay fixed.

The famous sums, converted

The widow’s two mites (Mark 12:41-44 ). The smallest denomination that existed, twice: about 1/64 of a day’s wage, roughly $2.40. The story requires the coin to be nearly worthless; that is the mechanism of “she of her want did cast in all that she had.” Luther minted a German word for the verse: Scherflein, which survives in the idiom “sein Scherflein beitragen” to this day.

Two hundred pennyworth of bread (Mark 6:37). The disciples’ estimate for feeding the five thousand: 200 denarii, some eight months of wages ($30,000). The number is their way of saying “impossible.”

Three hundred pence of ointment (John 12:5 ). Judas prices Mary’s spikenard at 300 denarii, a year’s wages in a jar ($45,000), poured out in one act. His indignation is in the number.

The thirty pieces of silver (Matthew 26:15). Thirty argyria, silver shekels, in the first century most plausibly Tyrian tetradrachms (the temple’s own approved coinage), each about four denarii: roughly 120 days’ wages ($18,000). Exodus 21:32 : “If the ox shall push a manservant or a maidservant; he shall give unto their master thirty shekels of silver”, the fixed compensation for a dead slave. Zechariah 11:12-13 stages the insult in advance: “So they weighed for my price thirty pieces of silver. And the LORD said unto me, Cast it unto the potter: a goodly price that I was prised at of them.” The chief priests valued the shepherd at the tariff of a gored slave, and the money ended at the potter’s field (Matthew 27:7-10 ), completing Zechariah’s script.

Ten thousand talents against a hundred pence (Matthew 18:23-35 ). The unforgiving servant owes 10,000 talents ≈ 60 million denarii ($9 billion), roughly 200,000 years of labor, a number chosen to be unpayable (Josephus records the annual tribute of entire provinces in mere hundreds of talents). His fellow servant owes him 100 denarii ($15,000), a real debt, four months’ wages by the same count, and utterly beside the point. The parable’s mercy ratio is about 600,000 to one.

Weights before coins

Old Testament “money” is weighed, not minted: coinage reaches Judea only in the Persian period. Abraham “weighed to Ephron the silver… four hundred shekels of silver, current money with the merchant” (Genesis 23:16): the shekel (שֶׁקֶל , from shaqal, “to weigh”) is a weight of about 11 grams, long before it is a coin. The sanctuary shekel (Exodus 30:13), the half-shekel temple tax it defines, the talent (about 3,000 shekels), and the mina sit in the same weight system. This is why dishonest scales are a covenant offense: “a false balance is abomination to the LORD” (Proverbs 11:1 ).

References

Mishnah, Shekalim: administration of the half-shekel temple tax.
Josephus, Antiquities 17.11.4: provincial annual tributes measured in hundreds of talents, the scale against which Matthew 18’s ten thousand talents is hyperbole.