Clock hands and numbers

Two or three hands and twelve numbers: the basics of reading a clock face, why it turns the way it does, and what to know before replacing a hand.

Which hand is which

Most analog clocks have two hands, and many have a third. The short, usually wider hand is the hour hand: it goes once around the dial every twelve hours. The long hand is the minute hand: it goes around once an hour. A thin third hand, if there is one, is the second hand, which goes around once a minute.

A clock parts seller, Clockworks, notes that the second hand is usually the longest of the three, the minute hand should reach close to the minute marks, and the hour hand should reach the hour numbers without being too long.

See also: printable clock faces with hours and minutes on OnlineClock.app.

How many numbers are on a clock

A standard clock face has 12 numbers, from 1 at the top right around to 12 at the top. Each number marks an hour for the hour hand, and five minutes for the minute hand, so the 3 means 15 minutes past and the 6 means half past.

The question is also a well-known riddle, because people sometimes count digits instead of numbers. The straightforward answer is 12. Some dials use Roman numerals instead, and a 24-hour dial shows 24 hours around the face.

See also: learning to tell time on an analog clock on OnlineClock.app.

Why hands turn clockwise

No one wrote down the reason, but the usual explanation is the sundial. In the northern hemisphere, where nearly all early clocks were made, the shadow on a sundial sweeps around in the same direction clock hands now turn. Country Life notes that this is unproven but sensible: early makers simply copied the shadow.

There are a few famous clocks that run the other way. Country Life lists Paolo Uccello's clock in Florence Cathedral, the Hebrew-lettered clock on the Jewish Town Hall in Prague, and a clock added to Bolivia's congress in 2014.

One hand or two

Early clocks often had only an hour hand. The Trowbridge Museum, describing English longcase clocks, notes that cheaper thirty-hour clocks usually had a single hour hand, while finer eight-day clocks had both hour and minute hands.

On a one-handed clock you read the time from where the hand sits between the hours, which is good enough for daily life when clocks were not very accurate anyway.

Names of hand styles

Hands come in many shapes, and replacement sellers use names for them. Clockworks describes spade hands, which end in a decorative spade shape and are common on traditional clocks; Breguet hands, with a hollow circle near the tip; dauphine hands, wide at the base and tapering to a sharp point; and alpha hands, which are slim and elongated.

Serpentine hands, with a wavy minute hand, and tapered hands are also common. On grandfather and mantel clocks, matching hands in the same style and length as the originals keeps the dial looking right.

Replacing clock hands

Measure a hand from the center of its mounting hole to its tip. The hole has to match the shaft of the movement: Esslinger, a clock parts supplier, says to check that the hour and minute hand holes fit the new movement's shaft size and shape before reusing old hands.

Make sure the hands do not touch each other, the dial or the glass. Troubleshooting guides list touching hands as a common reason a clock stops. Long or heavy hands may need a high-torque movement.

Keep exploring

Sources

1. Types of clock hands, Clockworks
2. Curious questions: why do clocks go clockwise?, Country Life (2020)
3. Object A to Z: L is for long-case clock, Trowbridge Museum
4. How to determine a quartz clock movement's shaft size, Esslinger
5. Troubleshooting your Howard Miller clock, Frankenmuth Clock Company

More clock guides

How to identify an antique clock and judge its value · Clock movements explained · Grandfather clock weights, winding and care · Why clocks use IIII instead of IV · Tempus fugit: the motto on the clock · How to date a watch by its serial number · The Westminster chime · all guides