Generations
| Model | Size | Built around | Used market | Enclosed cab |
|---|---|---|---|---|
| Komatsu D21PL-5 | 0-75 hp | — | rare | — |
| Komatsu D21PG | 0-75 hp | — | rare | — |
| Komatsu D21PL-6 | 0-75 hp | — | rare | — |
| Komatsu D21P-5A | 0-75 hp | 1984 | rare | — |
| Komatsu D21A-5 | 0-75 hp | 1985 | known | 19% |
| Komatsu D21E-6 | 0-75 hp | 1988 | known | — |
| Komatsu D21A-6 | 0-75 hp | 1990 | common | 18% |
| Komatsu D21P-6LGP | 0-75 hp | 1990 | rare | — |
| Komatsu D21P-6 | 0-75 hp | 1991 | common | 11% |
| Komatsu D21A | 0-75 hp | 1992 | known | — |
| Komatsu D21P-7LGP | 0-75 hp | 1992 | rare | — |
| Komatsu D21P-5 | 0-75 hp | 1994 | known | 11% |
| Komatsu D21P-5LGP | 0-75 hp | 1995 | rare | — |
| Komatsu D21A-7 | 0-75 hp | 1996 | common | 12% |
| Komatsu D21P-7E | 0-75 hp | 1996 | rare | — |
| Komatsu D21Q7 | 0-75 hp | 1996 | rare | — |
| Komatsu D21 | 0-75 hp | 1997 | rare | — |
| Komatsu D21A-7E | 0-75 hp | 1997 | rare | — |
| Komatsu D21P | 0-75 hp | 1998 | known | 17% |
| Komatsu D21P-7 | 0-75 hp | 1998 | known | 11% |
| Komatsu D21PL | 0-75 hp | 1998 | rare | — |
| Komatsu D21P-6A | 0-75 hp | 2000 | rare | — |
| Komatsu D21P7S | 0-75 hp | 2003 | rare | — |
| Komatsu D21A-8 | 0-75 hp | 2005 | rare | — |
| Komatsu D21P-8 | 0-75 hp | 2006 | rare | — |