Men's 400 metres world record progression

The first world record in the 400 m for men (athletics) was recognized by the International Amateur Athletics Federation, now known as the International Association of Athletics Federations, in 1912. The IAAF ratified Charles Reidpath's 48.2 performance set at that year's Stockholm Olympics as a world record, but it also recognized the superior mark over 440 yards (402.34 metres) run by Maxey Long in 1900 as a world record.

To June 21, 2009, the IAAF has ratified 23 world records in the event.^[1]

The following tables show the world record progression in the men's 400 metres, as ratified by the IAAF.

Records 1912–1976

Time	Auto	Athlete	Nationality	Location of race	Date
47.8y		Maxie Long	United States	New York, USA	September 29, 1900[1]
48.2		Charles Reidpath	United States	Stockholm, Sweden	July 13, 1912[1]
47.4y		Ted Meredith	United States	Cambridge, USA	May 27, 1916[1]
47.0		Emerson Spencer	United States	Palo Alto, USA	May 12, 1928[1]
46.4y		Ben Eastman	United States	Palo Alto, California, USA	March 26, 1932[1]
46.2	46.28	Bill Carr	United States	Los Angeles, USA	August 5, 1932[1]
46.1		Archie Williams	United States	Chicago, USA	June 19, 1936[1]
46.0		Rudolf Harbig	Germany	Frankfurt am Main, Germany	August 12, 1939[1]
		Grover Klemmer	United States	Philadelphia, USA	June 6, 1941[1]
46.0y		Herb McKenley	Jamaica	Berkeley, USA	June 5, 1948[1]
45.9	46.00	Herb McKenley	Jamaica	Milwaukee, USA	July 2, 1948[1]
45.8		George Rhoden	Jamaica	Eskilstuna, Sweden	August 22, 1950[1]
45.4	45.68	Louis Jones	United States	Mexico City, Mexico	March 18, 1955[1]
45.2		Louis Jones	United States	Los Angeles, USA	June 30, 1956[1]
44.9	45.07	Otis Davis	United States	Rome, Italy	September 6, 1960[1]
	45.08	Carl Kaufmann	West Germany	Rome, Italy	September 6, 1960[1]
44.9y		Adolph Plummer	United States	Tempe, USA	May 25, 1963[1]
44.9		Michael Larrabee	United States	Los Angeles, USA	September 12, 1964[1]
44.5+		Tommie Smith	United States	San Jose, USA	May 20, 1967[1]
44.1	44.19	Larry James	United States	Echo Summit, USA	September 14, 1968[1]
43.8	43.86	Lee Evans	United States	Mexico City, Mexico	October 18, 1968[1]

(+) plus sign denotes en route time during longer race
"y" denotes time for 440 yards, ratified as a record for this event

Records post-1976

From 1975, the IAAF accepted separate automatically electronically timed records for events up to 400 metres. Starting January 1, 1977, the IAAF required fully automatic timing to the hundredth of a second for these events.^[1]

Lee Evans' 1968 Olympic gold medal victory time of 43.86 was the fastest recorded result to that time.

Time	Athlete	Nationality	Location of race	Date
43.86	Lee Evans	United States	Mexico City, Mexico	October 18, 1968[1]
43.29	Butch Reynolds	United States	Zürich, Switzerland	August 17, 1988[1]
43.18	Michael Johnson	United States	Seville, Spain	August 26, 1999[1]

References