On one of your self employment tips website: You can claim 50% of what you pay in self-employment tax as an income tax deduction. How do I know I am getting this?

Also, My self-employment tax seems high for 6 months as a 1099. I was a W2 for 4 months (Unemployed for 2 months). Is Turbo Tax calculating the self-employment tax based on the whole year?