Why clocks use IIII instead of IV
Look at almost any clock with Roman numerals and the four is written IIII. It is not a mistake, but nobody agrees on a single reason. Here are the explanations, and which ones hold up.
IIII is not a mistake
Most people learn at school that 4 in Roman numerals is IV: one taken away from five. Then they look at a clock and see IIII. Clockmakers have been doing this for centuries on purpose, and many collectors call it the watchmaker's four.
The odd thing is that the same dials usually write 9 as IX, the subtractive way. So the choice of IIII is specific to the four, which is why people keep asking about it.
The Romans often wrote IIII themselves
The simplest explanation is history. The Romans did not follow the tidy rules taught today. Writing four as IIII was common in ancient Rome, and the subtractive IV became the standard form much later. Citizen notes that sundials from Roman times often show IIII too.
The Seiko Museum points out that the Wells Cathedral clock in England, from the end of the 14th century, already used IIII, and says IIII was generally used for clock dials until around the 17th century. In other words, early clockmakers may simply have been writing four the normal way of their time, and the habit stuck long after schoolbooks moved on.
The king who did not like IV
The most repeated story involves a king. In the version told by the Seiko Museum, King Charles V of France in the late 14th century was shown a clock with IV and ordered it changed to IIII. Other tellings name Louis XIV instead, and Mental Floss notes the same tale is told about different rulers, a good sign that it is a legend rather than a record.
A related story says IV looked too much like IVPPITER, the Roman spelling of Jupiter, so Romans avoided it out of respect. Citizen repeats this one but makes clear it has not been verified. Neither story explains why clockmakers in many countries kept using IIII for hundreds of years.
Balance on the dial
The explanation clockmakers like best is design. With IIII, the left side of the dial carries more weight: IIII sits opposite VIII, which is also a wide, heavy numeral. The Seiko Museum describes this balance with VIII as a reason IIII stayed popular.
There is a second pattern too. Going round a IIII dial, the first four numerals use only I, the next four use V, and the last four use X. Mental Floss describes this as a kind of radial symmetry that makes the dial look orderly at a glance. Some also argue IIII is easier to tell apart from VI when a dial is read upside down, since the numerals at the bottom of a clock are upside down to the viewer.
See also: how a clock face is laid out on OnlineClock.app.
The casting theory
A more practical idea concerns how numerals were made. If the numerals are cast in metal, a dial with IIII needs twenty I's, four V's and four X's. Mental Floss explains that this works out neatly: the numerals can be made from one mold containing one V, five I's and an X, used four times, with nothing left over. With IV, the numbers do not divide so neatly.
It is a clever explanation, but there is no record proving that early makers chose IIII because of molds. It is best treated as one more possible reason.
The famous exceptions
Not every clock follows the rule. Big Ben's great dials on the Elizabeth Tower in London use IV, and so do some other public clocks and watch brands that prefer the modern form.
Electric Time Company, a US maker of tower clocks, looked through a book of hundreds of tower clock photographs and found that about 95 percent of the dials with Roman numerals used IIII, with only a handful using IV. The company also lists the competing theories from clock writers, including the idea that IIII matched the way old striking clocks were sometimes counted. None has been proven, which is the honest answer: IIII is a tradition with several possible roots.
Reading a Roman numeral clock
If you are not used to Roman numerals, it helps to know just three symbols: I is one, V is five and X is ten. On a clock, VI is at the bottom, XII is at the top, III is on the right and IX is on the left.
When a smaller numeral comes before a larger one, take it away: IX is ten minus one, so nine. When it comes after, add it: XI is ten plus one, so eleven. The four, written IIII on most clocks, is simply four ones.
See also: a live Roman numeral clock to practise reading on OnlineClock.app.
Questions people ask
Why do clocks use IIII instead of IV?
There is no single proven reason. The likely ones are that the Romans often wrote IIII, that early clock dials used it and the habit stuck, and that IIII balances the VIII on the other side of the dial. Stories about a king ordering the change are legends.
Is IIII wrong?
No. IIII was widely used in Roman times and on clocks for centuries. IV became the standard form taught in schools later.
Does Big Ben use IIII or IV?
Big Ben's dials use IV, one of the best-known exceptions to the IIII tradition.
Why is 9 written IX on the same clocks?
Clockmakers kept the subtractive IX while using IIII for the four, which is one reason the IIII choice is thought to be about tradition and dial balance rather than strict rules.
Keep exploring
Sources
- Why is the numeral 4 written IIII on clocks?, Seiko Museum Ginza
- Why do watches and clocks with Roman numerals use IIII instead of IV?, Citizen Watch support
- Why do some clocks use Roman numeral IIII?, Mental Floss
- Roman IIII vs IV on clock dials, Electric Time Company
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