| Kalkar to Navodari | 1,145.38 mi (1,843.31 km) |
| Kalkar to Negresti-Oas | 807.10 mi (1,298.90 km) |
| Kalkar to Nehoiu | 1,011.74 mi (1,628.24 km) |
| Kalkar to Ocna Mures | 874.04 mi (1,406.63 km) |
| Kalkar to Odobesti | 1,027.77 mi (1,654.03 km) |
| Kalkar to Odorheiu Secuiesc | 935.71 mi (1,505.88 km) |
| Kalkar to Oltenita | 1,075.11 mi (1,730.23 km) |
| Kalkar to Onesti | 998.23 mi (1,606.50 km) |
| Kalkar to Oradea | 771.05 mi (1,240.89 km) |
| Kalkar to Orastie | 867.63 mi (1,396.32 km) |
| Kalkar to Oravita | 841.78 mi (1,354.72 km) |
| Kalkar to Orsova | 882.53 mi (1,420.29 km) |
| Kalkar to Otelu Rosu | 847.38 mi (1,363.72 km) |
| Kalkar to Otopeni | 1,033.60 mi (1,663.42 km) |
| Kalkar to Ovidiu | 1,145.21 mi (1,843.04 km) |
