# How do you convert Raw Alignment Score to Bit Score?

I'm coding a pipeline where I make a lot of pairwise alignments, and I end up with raw alignment scores. But, I really need to look at my results in terms of bit scores.

I know that the formula is:

$$𝑆′ = (ƛ*𝑆 − 𝑙𝑛(𝐾)) / 𝑙𝑛(2)$$

But, I don't know what ƛ or K would be. I'm currently using BLOSUM62.

I've looked around online for how to look up (and even empirically deduce) lambda and k, and I all I've come across were convoluted explanations.

I also know that this question from almost 3 years ago attempts to address the same topic, but the best response only leads to an NCBI link that requires login credentials.

Any help would be much appreciated.

wget https://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/LATEST/ncbi-blast-2.11.0+-src.tar.gz

Then, extract the files and look at the file c++/src/algo/blast/core/blast_stat.c which, again according to the answer you linked to, should have the lamda and k tables at line 589.