Why would my federal tax credit drop from $2500 to $1000 this year. My taxes are virtually the same?

If you are asking about a lower refund this year as compared to last year, then there are usually two causes.  The first and most prevalent is tax withholding for the year did not keep up with income. 

So if your income stayed virtually the same you will want to look at line 25 on your 2019 and 2020 returns to see how withholding changed between the years.

The other common reason for a refund drop is not qualifying for a credit or qualifying for a lower amount of credit in 2020 than you may have qualified for 2019.  You need to look at lines 21 and 32 to see what credits may have changed.

To see a form view in TurboTax online,    

1. Click "Tax Tools" in the left hand menu
2. Click "Tools"
3. Click "View Tax Summary"
4. Click "Preview My 1040" in the left hand menu

If you need to adjust withholding to have more money withheld from your pay to get a bigger refund, you need to work with your employer to produce an updated form W4.  Here is a calculator that will help.

[edited 2/17/2021 3:16 pm EST]