API calls generated by executing Data Loader operations count toward your organization’s API usage limits.
The number of API calls depends on the number of records processed and the batch size (the number of records handled in a single API call).

How API Calls Are Counted in Data Loader

For example, if Batch Size = 200 is configured in the Data Loader Settings menu, one upsert() API call processes 200 records.
In this case, the estimated* number of API calls is calculated as:

Number of records in the CSV file ÷ Batch Size

* In practice, additional API calls are made—for example, one API call during login and another when fields are retrieved after selecting an object. Therefore, the actual number of API calls will be slightly higher than this estimate.

Objects Included in API Call Counting

All objects are subject to API call counting.

How to Check if the API Limit Has Been Exceeded

You can check your organization’s API usage limits by navigating to:

Setup > System Overview

On the System Overview page, refer to the API Requests, Last 24 Hours field.
For example, if it displays “22 (Max 5,000)”, this means that 22 API requests have been made in the past 24 hours, and up to 5,000 API requests can be processed within a 24-hour period.

Definition of “1 Day (24 Hours)”

The 24-hour period is defined as the rolling 24 hours from the current time (hour and minute).

Additional Notes

For delete operations, there are additional limits beyond API call usage.