| S.N | RBC | WBC |
| 1. | RBC stands for red blood cells. | WBC stands for white blood cells. |
| 2. | They are also known as erythrocytes. | They are also known as leucocytes. |
| 3. | They are small biconcave and non nucleated. | They are comparatively larger, amoeboid and nucleated |
| 4. | Much more in number. | Much less in number. |
| 5. | Around 5 million rbc’s per cubic mm of blood. | Around 11000 wbc’s per cubic mm of blood. |
| 6. | Red in colour due to the presence of haemoglobin. | Non-pigmented and hence colourless. |
| 7. | Life span is about 120 days. | Life span is 5-21 days. |
| 8. | Formed in bone marrow of vertebrae, ribs and pelvis. | Formed in bone marrow, lymph gland, thymus, spleen. |
| 9. | Are called oxygen carriers. | Are called phagocytes. |
| 10. | Carry oxygen from the lungs to the body tissues and help in respiration. | Play an important role in body’s defence system by engulfing bacteria. |
| 11. | No types are present. | Various types are present. |
| 12. | Move only in blood vessels. | Move in blood vessels and lymph vessels. |
| 13. | Formation process called erythropoiesis. | Formation process called leucopoiesis. |
| 14. | Form stacks or aggregation known as rouleaux. | Do not form rouleaux. |
| 15. | Decreased condition is called anaemia. | Decreased condition is called leukopenia. |
| 16. | Increased condition is called polycythemia. | Increased condition is called leukocytosis and leukaemia. |
| 17. | Accounted for 40-45% of total blood volume. | Accounted for 1% of total blood volume. |

Image source: biologydictionary
References:
i) https://www.toppr.com/guides/biology/difference-between/rbc-and-wbc/
ii) https://pediaa.com/difference-between-red-blood-cells-and-white-blood-cells/