If your 2020 Child Tax Credit is less than your 2019 credit, it's probably because one or more children celebrated their 17th birthday in 2020.
Other, less common reasons your 2020 Child Tax Credit is less than your 2019 credit include:
- One or more children lived with you for less than half the year in 2020 but lived with you for half the year (or more) in 2019.
- One or more children paid more than half of their own expenses in 2020, but didn't in 2019.
- Your 2020 AGI increased to $400,000 or more (joint filers) or $200,000 or more (all others).