This estimates how many sats/vbyte you need to bump your child tx to get your desired parent fee in mempool.
git clone https://github.com/jtymoszczuk/cpfp-calc.git
cd cpfp-calc
./cpfp-calc.sh
Enter the total amount of sats your current(parent) tx cost?
What fee do you want your tx to be in sats/vbyte?
Virtual size of parent transaction.
Virtual size of child transaction.