Verifying email addresses is a complex, time intensive process whereby our systems interact with external mail systems. Whilst we have control over our own systems, we have no control over remote mail systems and how they behave from a functionality and performance perspective. For this reason, it is not possible to provide a definitive time for completion of the verification process. However, we can provide some approximations based on our many years experience in this industry.


In the table below we have provided  average processing times  for various file sizes. Please be aware these times may vary due to reasons beyond our control such as:


  • The current demand on Email Hippo services.

  • The amount of email addresses contained within the list that employ grey listing. To try to validate the email address we re-try the address 5 times (free of charge) with larger periods of time between each retry. 

  • The amount of email addresses contained in the list that employ tarpitting


All of these factors will delay the verification process.


Amount Of Unique Emails within List

Processing duration

From                                                             To

1,000

30 minutes 

3 hours

2,500

1 hour

4 hours

5,000

2 hour

5 hours

10,000

3 hours

6 hours

25,000

4 hours

7 hours

50,000

5 hours

8 hours

75,000

6 hours

9 hours

100,000

7 hours

10 hours

200,000

8 hours

11 hours

250,000

9 hours

12 hours

300,000

10 hours

13 hours

400,000

11 hours

14 hours

500,000

12 hours

15 hours

       Please be aware these are approximate times only and are not guaranteed. Your file may take less or more time.