State tax filing

Connecticut will not tax your Massachusetts income. It does use your total income set your base tax rate.

For example, if you earned $50,000 total and $25,000 in CT, your tax rate would be based on $50,000. Say the CT tax on $50,000 is $5,000. Then your tax would be 50% ($25,000/$50,000) of $5,000 or $2,500.

Look at your CT-1040NR/PY return. The allocation is shown on lines 8-10.