New 401(k) contributions are not reported on your tax return as taxable income so your total taxable income and the tax will be lower, but when the money is finally distributed to you it will be taxable.
401(k) Roth contributions are included in you taxable income. When you finally take the money out it will be tax free since you already paid the tax.
How much difference in your tax depends on your total income from all sources and margional tax rate.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
