Why do some clocks use the roman numeral IV on their dials, while others use IIII in the place of number four? As clock and watch designers it’s a question that we’ve spent a lot of time thinking about.

There are several conflicting theories on whether it should be IIII or IV on a clock face, and no definitive answers. Here are just some of the theories on why IIII came to be most commonly used:

When Roman numerals were in use by the Roman Empire, the name of the Romans' supreme deity, Jupiter, was spelled as IVPPITER in Latin. There was a feeling that using the start of Jupiter’s name on a clock dial, and it being upside down where it fell, would be disrespectful to the deity, so IIII was introduced instead.

King Louis XIV of France supposedly preferred IIII over IV, and so he ordered his clockmakers to use the former. Some later clockmakers followed the tradition, and others didn't. 

Traditionally using IIII may have made work a little easier for clock makers. If you're making a clock where the numerals are cut from metal and affixed to the face, using IIII means you'll need twenty I's, four V's, and four X's. That's one mould of "XVIIIII" which you can cast four times and have the right number of digits for your dial. If you use IV, the totals are four, seventeen, and five, which doesn't divide up so neatly, and therefore requires several moulds in different configurations.

For those logically-minded souls amongst us, then using IIII makes more numerical sense when the clock dial is viewed as a whole. This arrangement means I is seen at the start of the first four hour markings on the dial, V is seen at the start of the next four markings, and X is seen only in the last four markings, creating radial symmetry. 

The main reason that we at Newgate favour the IIII on all of our clocks and watches, is all down to aesthetics. We feel that using IIII creates more visual symmetry with the VIII opposite it on the clock face than IV does, creating a greater sense of balance within our designs.

One notable contradiction to most clock makers preference for the IIII, is London’s iconic Big Ben clock tower. Dating from the 1850’s this landmark timepiece is a rarity in favouring the IV approach.