ROMAN COINS - HOW MANY WERE MADE?

Ken Pilon  - November, 2020

 Roman coins for sale in the Forum Ancient Coins shop

There has always been speculation as to how ancient Roman moneyers made their coins and how many coins were ultimately made.  Let’s have a look at how many coins Imperial Rome may have produced.

Roman Coin Production Record Keeping

As the Romans didn’t keep production records we’ll have to rely on statistical probabilities to estimate it, plus a few assumptions.

The Number of Strikes from a Coin Die

The number of coins that could be struck from a single die before it was discarded is thought to average ~27,250(1).  A coin die is believed to have lasted for an average of six months under moderately heavy use before needing replacement(1).  This yields an average production of ~150 coins per day from a single obverse/reverse die set.

Number of Coin Types and Their Variations

The total number of Roman Imperial coin types produced was ~7,200(2) and the total number of varieties of each coin type averages 6.7(2) or 48,012.  This yields a total of ~55,312(2)(5) different coin varieties produced during the entire period of the Roman Empire.

Coin Production Period of a Typical Roman Coin Variety

This averaged 3.0 years(2).

Coin Denomination Percentage Minted by Imperial Rome

Roman Coin Production Calculation - Part One

At least one set of dies would have been produced for each of the 55,000 coin varieties.  With each die set good for an average of ~27,250(1) maximum strikes a total Empire production of 1.5 billion coins (55,000 x 27,250) could be produced using a single die set for each variety.  As big as 1.5 billion coins is, was it enough for the Empire?  Let’s check it out.

The Empire lasted 503 years (27BC-476AD).  Let’s assume the average coin lasted 30 years before it was lost or became too worn to use any more.  Dividing 1.5 billion coins by its average 30 year lifespan over the course of the 503 year old Empire yields an average of 89 million coins in circulation at any given time.  The average population of the Empire was ~55 million(4), or about 35 million adults.  Dividing 66 million circulating coins by its adult population of 35 million yields an average adult to possess just 2.6 coins each and a median even less at ~2.2 coins each (depending on how many wealthy possessed hundreds or thousands of coins each).  Therefore a total of 1.5 billion coins produced using a single die set for all 55,000 coin varieties does not seem realistic, they must have minted more.

So just how many coins were produced and how many die sets were used for each coin variety?  An estimate for those answers can also be calculated.

Roman Coin Production Calculation - Part Two

In the 2nd century AD an average of 17 million denarii were produced annually(3).  During this century these denarii represented ~31%(5) of the entire Roman coin production.  Dividing one by the other yields an average of 55 million coins produced for each year of the 2nd century.  This century also saw the Empire at its greatest height, its largest population and probably its greatest coin producing period.  If we assume that the entire period of the Empire produced an average of 40 million coins per year then the Empire’s total 503 year production comes in at ~20 billion coins.  This works out to an average of ~13 die sets for each of the 55,000 coin varieties.

Is This Massive 20 Billion Coins Realistic?

Remember, the Empire lasted 503 years and we are assuming an average coin lifespan of 30 years.  We now divide the estimated 20 billion produced coins by their average 30 year lifespan in the 503 year long Empire.  This yields an average of 1.2 billion coins in circulation at any given time.  Dividing 1.2 billion circulating coins by the Empire’s 35 million adult population yields an average of ~34 coins each or a median of about 29 coins each.  Therefore, a total of 20 billion Roman coins produced during the 503 year long Empire seems realistic.

How Many Roman Coins Survive Today?

Unknown as there’s no data.  I’d estimate there are about 25 million surviving Roman coins today with about 400,000 collectors world-wide.  These coins are probably divided 80% among collectors and the remaining 20% for hoards, museums and dealer inventories.  This would mean that only about 1 in 800 Roman coins have been found and survives today.

Please Note 

Some of the numbers used here are estimates, speculative or are subjective assumptions.

References:

1 - Howgego, Christopher.  Ancient History from Coins. London (1995).

2 - Data extracted from Rasiel Suarez’s ERIC II (2010).

3 - Classical Coins (http://www.classicalcoins.com/page103.html).  How Ancient Coins Were Made.

4 - Wikipedia.  Demography of the Roman Empire.

5 - American Numismatic Society (http://numismatics.org/ocre/).  Online Coins of the Roman Empire (OCRE).