1. ^For the 1949 season 1 point awarded to the competitor recording the fastest lap if finished the race
2. ^The 1949 season the best of 3 race results counted for 250cc & 350cc championships and all of the results for the 125cc & 500cc sidecar championships.
3. ^^{1 2 3 4 5 6 7 8 9 10 11 12} The number of championship rounds divided by two, plus one
4. ^The 1950 season the best of 4 race results counted for 350cc championship and all of the results for the 125cc, 250cc & 500cc sidecar championships.
5. ^The 1951 season the best of 5 race results counted for 350cc championship, best of 4 results for 250cc & 500cc sidecar championships and all of the results for the 125cc championship.
6. ^The 1952 & 1953 seasons, the best of 4 race results counted for 125cc, 250cc, 350cc and 500cc sidecar championships.
7. ^The 1954 season the best of 5 race results counted for 350cc and the best of 4 race results counted for 125cc, 250cc and 500cc sidecar championships.
8. ^The 500cc race for 1954 Ulster Grand Prix for the World Championship was excluded by the FIM as a points scoring round after heavy rain reduced the race distance.
9. ^The 1955 season the best of 4 race results counted for 125cc, 250cc, 350cc and 500cc sidecar championships.
10. ^The 1956 & 1957 seasons the best of 4 race results counted for 125cc, 250cc, 350cc and 500cc sidecar championships.
11. ^The 1958 season the best of 4 race results counted for 125cc, 250cc, 350cc championships and the best of 3 race results counted for the 500cc sidecar championship.
12. ^The 1959 season the best of 4 race results counted for 125cc, 250cc, 350cc championships and the best of 3 race results counted for the 500cc sidecar championship.
13. ^The 1960 season the best of 4 race results counted for 250cc championship and the best of 3 race results counted for 125cc, 350cc and the 500cc sidecar championships.
14. ^The 1961 season the best of 4 race results counted for the 350cc championship, the best of 6 race results counted for the 125cc and 250cc championship and the best of 4 results for the 500cc sidecar championships.
15. ^The 1962 season the best of 4 race results counted for the 350cc championship, the best of 6 race results counted for the 50cc, 125cc and 250cc championship and the best of 4 results counted for the 500cc sidecar championship.
16. ^The 1963 season the best of 6 race results counted for the 150cc and 350cc championship, the best of 7 race results counted for the 250cc championship and the best of 4 results counted for the 50cc solo and 500cc sidecar championships.
17. ^The 1964 season the best of 5 race results counted for the 50cc and 350cc championship, the best of 6 race results counted for the 250cc championship and the best of 4 results counted for the 500cc sidecar championship.
18. ^The 1965 season the best of 5 race results counted for the 50cc and 350cc championship, the best of 7 race results counted for the 125cc and 250cc championship and the best of 4 results for the 500cc sidecar championships.
19. ^The 1966 season the best of 6 race results counted for 350cc championship, the best of 7 race results counted for the 250cc championship, the best of 6 race results counted for the 125cc championship, the best of 4 race results counted for the 50cc championship and the best of 3 results for the 500cc sidecar championships.
20. ^The 1967 season the best of 5 race results counted for the 350cc championship, the best of 7 race results counted for the 125cc and 250cc championship, the best of 4 race results counted for the 50cc championship and the best of 5 results for the 500cc sidecar championships.
21. ^The 1968 season the best of 4 race results counted for the 350cc championship, the best of 6 race results counted for the 250cc championship, the best of 5 race results counted for the 150cc championship, the best of 3 race results counted for the 50cc championship and the best of 4 results for the 500cc sidecar championships.
22. ^The 1969 season the best of 6 race results counted for the 50cc, 125cc and 350cc championships, the best of 7 race results counted for the 250cc championship and the best of 4 results for the 500cc sidecar championships.
23. ^The 1970 season the best of 6 race results counted for the 50cc, 125cc and 350cc championship, the best of 7 race results counted for the 250cc championship and the best of 5 results for the 500cc sidecar championship.
24. ^The 1971 season the best of 5 race results counted for the 50cc championship, the best of 7 race results counted for the 125cc, 250cc & 350cc championships and the best of 5 results for the 500cc sidecar championship.
25. ^The 1972 season the best of 5 race results counted for the 50cc championship, the best of 7 race results counted for the 125cc, 250cc & 350cc championships and the best of 5 results for the 500cc sidecar championship.
26. ^The 1973 season the best of 4 race results counted for the 50cc championship, the best of 7 race results counted for the 125cc championship, the best of 6 results for the 250cc & 350cc championships and the best of 5 results for the 500cc sidecar championships.
27. ^The 1974 season the best of 6 results for the 50cc, 125cc, 250cc & 350cc championships and the best of 5 results for the 500cc sidecar championships.
28. ^The 1975 season the best of 5 race results counted for the 50cc championship, the best of 6 results for the 125cc, 250cc & 350cc championships and the best of 4 results for the 500cc sidecar championships.
29. ^{{cite book | title=Motocourse 1976–1977 | publisher=Hazleton Securities Ltd. | editor-last = Carter | editor-first = Chris | pages=33, 185 | isbn=0-905138-02-3}}
30. ^{{cite book |title=Guinness Motorcycle Sport Fact Book |first=Ian |last=Morrison |page=14 |date=1991 |edition=1st |publisher=Guinness Publishing – The Bath Press |isbn=978-0-85112-953-2}}