OP, I am really bad with math and tax rates and such. But I tried to figure this out for you anyhow.
Your gross income is $70,000 a year. I'm assuming you live in MD and pay a state tax of 5% on that income, and that you pay a federal income tax rate of 25% on that income.
The maximum you can put into a 401K each year is $18,000 which is a contribution rate of about 25% of your gross salary.
Using this calculator I get:
https://nb.fidelity.com/public/nb/401k/tools/calculators/takehomepay
$673
Is your bi-weekly pre-tax contribution to your retirement plan account.
$471
Is an estimation of how much your bi-weekly take home pay will be reduced by.
And this calculator says that if you live in Maryland, and earn $70,000 yearly, your biweekly paycheck would be:
Gross Pay 2692.31
Federal 256.75
Fica 166.92
Medicare 39.04
State 92.26
401K 673.08 (This isn't the same as what I got above)
Net Pay 1464.26
https://www.adp.com/tools-and-resources/calculators-and-tools/payroll-calculators/salary-paycheck-calculator.aspx