This article assumes that you have already registered for your online tools account here:

https://www.ups.com/upsdeveloperkit?loc=en_US

And have already been given a USER ID and your account is active.

1) Go to UPS.com and obtain an account. Go to Business Solutions and search for Online Tools. Follow the steps to obtain a valid user id:

2) Go to Magento Admin → Configuration → Shipping Methods → UPS

Gateway URL is: http://www.ups.com/using/services/rave/qcostcgi.cgi

This allows customers to connect to the main UPS shipping calculator for shipping costs at checkout.