See How are API calls consumed by Data Loader?
The number of batches submitted for a data manipulation operation
depends on the number of records and batch size selected. The total
number of records in your file divided by the batch size selected
equals the number of batches. Each batch consumes one API call.
The default batch size in Data Loader is 200 or if you select the
"Enable Bulk API" setting the default batch size is 2,000.
For example, with an API request limit of 15,000 and a batch size of 200 it would be possible to perform operations on (15,000 X 200) or 3,000,000 records per 24 hours.
If using the "Enable Bulk API" option with Data Loader and a batch size of 2,000 it would be possible to perform operations on (15,000 X 2,000) or 30,000,000 records per 24 hours.