We've just updated the "Max Out Your TSP" table for the proposed 1.6% military active duty pay increase for 2012. Here's the link.
Here's how you use it. In this example, a Major (O-4) with more than 18 years of service would go to MyPay.gov, select the TSP link, and select 19.8% as their monthly contribution.
Similarly, a Lieutenant Colonel with 16 years of service would contribute 18.2% of their base pay to max out their TSP for the year.
Here are a couple of notes. First, this table assumes that the Congress will approve the 1.6% increase and that the President will sign the bill into law. Second, it assumes that you will want to max out the TSP at $17,000 for the year. If you are older than 50 the max contribution is $22,500. This table does not account for the extra $5,500 catch up provision.