The following should help:
What are the qualifications for the Earned Income Credit
(EIC or EITC)?
https://ttlc.intuit.com/replies/3299933
The EIC (Earned Income Credit) is a range based on the amount of
earned income you have, your filing status, and the number of qualifying
children you have. If you earn too little or too much, the amount you
receive for the credit is scaled based on that amount. Most taxpayers who
qualify for the credit will not receive the full amount.
You can read more about the income ranges for your filing status
and number of qualifying children below.
https://ttlc.intuit.com/replies/3299933
Also see
this for income ranges and amounts of the credit: 2016 EIC Table
