| Kalkar to Smolyan | 1,114.48 mi (1,793.59 km) |
| Kalkar to Sofia | 1,010.33 mi (1,625.97 km) |
| Kalkar to Sopot | 1,065.23 mi (1,714.33 km) |
| Kalkar to Sozopol | 1,188.75 mi (1,913.11 km) |
| Kalkar to Sredets | 1,172.33 mi (1,886.69 km) |
| Kalkar to Stamboliyski | 1,081.66 mi (1,740.77 km) |
| Kalkar to Stara Zagora | 1,109.21 mi (1,785.09 km) |
| Kalkar to Svilengrad | 1,161.14 mi (1,868.68 km) |
| Kalkar to Svishtov | 1,044.45 mi (1,680.88 km) |
| Kalkar to Targovishte | 1,108.46 mi (1,783.89 km) |
| Kalkar to Teteven | 1,034.71 mi (1,665.21 km) |
| Kalkar to Troyan | 1,053.16 mi (1,694.89 km) |
| Kalkar to Tryavna | 1,083.62 mi (1,743.92 km) |
| Kalkar to Tutrakan | 1,075.83 mi (1,731.38 km) |
| Kalkar to Varna | 1,162.44 mi (1,870.77 km) |
