Narrative:

ATC instructed us to climb and maintain 11;000 ft. At a fix. Prior to this instruction; we were flying a northeast direction towards the fix at 9000 ft. The first officer read back the instruction to ATC; I set 11;000 ft.; we both verified it; and I established a climb to 11;000 ft. At approximately 10;700 ft. And a few miles west of the fix; ATC stated; I told you to climb to 11000 at xxxxx. I did not realize ATC wanted us to maintain 9000 until reaching xxxxx then climb to 11;000. ATC queried us at approximately 10;700 ft. Just prior to the fix. I thought ATC cleared us to 11;000 feet prior to reaching the fix. The first officer acknowledged ATC's comment to us regarding our altitude. At this point we were crossing at 11000 ft. And continued on course to our destination.

Google
 

Original NASA ASRS Text

Title: An Air Carrier pilot reported they misunderstood an ATC climb clearance and climbed before they were supposed to.

Narrative: ATC instructed us to climb and maintain 11;000 ft. at a fix. Prior to this instruction; we were flying a northeast direction towards the fix at 9000 ft. The First Officer read back the instruction to ATC; I set 11;000 ft.; we both verified it; and I established a climb to 11;000 ft. At approximately 10;700 ft. and a few miles west of the fix; ATC stated; I told you to climb to 11000 at XXXXX. I did not realize ATC wanted us to maintain 9000 until reaching XXXXX then climb to 11;000. ATC queried us at approximately 10;700 ft. just prior to the fix. I thought ATC cleared us to 11;000 feet prior to reaching the fix. The First Officer acknowledged ATC's comment to us regarding our altitude. At this point we were crossing at 11000 ft. and continued on course to our destination.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.