Calibre 5100 is an automatic chronograph movement made by Lemania from 1974 through 2002.

The Lemania 5100 is a legendary workhorse of a movement, constructed from stamped steel, delrin plastic, and other simple materials. It was designed to compete with emerging inexpensive movements from Seiko and others, and to be cheap to assemble and service. It is an automatic chronograph like the contemporary Valjoux 7750 and features a similar “6-9-12” arrangement of subdials. One important difference is that the Lemania 5100 has chronograph minutes on the central axis along with chronograph seconds, giving watches using this movement a distinctive “four-handed” look.

A 12-hour chronograph counter is at 6 00, small seconds at 9 00, and a 24 hour subdial at 12 00. One or more of these subdials are sometimes omitted, further differentiating watches that use this movement. Perhaps the most unusual Lemania 5100 watch is the Sinn EZM 1, with no subdials at all and the crown and pushers located on the left side of the dial.

The Lemania 5100 was quite successful, outlasting the Valjoux 7750 line in the late 1970s, but was unable to compete as movement decoration became more important. Unlike competing movements, the Lemania 5100 was not suitable for display casebacks and did not adapt well to additional complications. Lemania's new corporate parent, ETA, re-designed the more attractive and conventional predecessor Cal. 1340 as Cal. 1350 in 1994. Production of Cal. 5100 ended in 2002 and watches that used it, including the famous Sinn Model 140 "Space Chronograph" were unavailable once supplies were exhausted until alternatives like Sinn's SZ01 could be developed.

In 2008, Tissot requested a low-cost mass-produced chronograph movement for entry-level Swiss watches. ETA created Cal. C01.211 based on the Lemania 5100 design. Jewel count was reduced to 15, operation slowed to 21,600 A/h, and the minute counter was moved to the 12 00 position.

Introduced in 1974, Cal. 5100 followed closely after the introduction of Lemania's similar Cal. 1340 family. Like that movement, it features an unusual arrangement of chronograph counters

• Central hour and minute hands, chronograph seconds, and 60 minute chronograph totaliser
• 12-hour totaliser at 6 00
• Small seconds at 9 00
• 24 hour hand at 12 00
• Day and date windows at 3 00

It has 17 jewels, hacking seconds, and power reserve of 48 hours, and operates at 28,800 A/h.

Cal. 5100's predecessor, Cal. 1340, was refreshed and re-launched as a successor, Cal. 1350, in 1994. The Lemania 5100 design has been reused as the ETA C01.211.

• Omega Cal. 1045
• Lemania 5012 - 21,600 A/h version with no 24 hour register

• Hall of Fame: Lemania 5100
• Chronography 4: Lemania 5100