Post-9/11 vs. Montgomery GI Bill®: how the payments differ

What each program pays

Two details change how the MGIB-AD column reads. VA pays it for each full month of enrollment and prorates a partial month by the days enrolled. And it steps down with course load: $1,950.75 at 75% enrollment, $1,300.50 at 50%, and $650.25 at 25% or less for the 3-year rate. Under half time, VA pays no more than the cost of tuition and fees (up to $1,300.50 above 25% and below 50%).

Different requirements, different benefit levels

VA’s Post-9/11 page sets the requirement at 90 days of active duty on or after September 11, 2001 (all at once or with breaks), or a Purple Heart on or after that date with an honorable discharge, or at least 30 continuous days and an honorable discharge with a service-connected disability. Your total active-duty days then set a benefit level from 50% to 100% that scales tuition, housing and books; at 1,095 days (36 months) the level is 100%. The Post-9/11 guide has the full tier table.

The MGIB-AD works differently. VA’s page describes four categories and requires an honorable discharge. Category I combines a high school diploma, GED or 12 hours of college credit, a first entry to active duty after June 30, 1985, military pay reduced by $100 a month for the first 12 months of service, and continuous service of 3 years (or 2 years if that was the enlistment agreement, or 4 years if you entered the Selected Reserve within a year of leaving active duty). Other categories cover different dates and a $1,200 pay reduction before separation (Category III) or a $1,200 lump-sum contribution (Category IV). VA says you usually have 10 years to use MGIB-AD benefits, while Post-9/11 benefits don’t expire for service that ended on or after January 1, 2013.

VA’s MGIB-AD rate tables don’t use a benefit-level percentage. The 3-year and 2-year rates are separate dollar tables, the program type matters too (on-the-job training pays different amounts), and VA adds a kicker or $600 Buy-Up amount on top when one applies.

Worked examples

We ran four students through the calculator’s engine for October 28, 2026. All have 1,200 days of service (100% level); the first three take 24 credits a year and the fourth takes 18, and the MGIB-AD column assumes the 3-year rate. Where a student takes three-quarters of a full load, the calculator’s rate of pursuit rounds 75% up to 80% for the Post-9/11 housing figure, as VA’s rates page describes.

The housing column is the January 2026 BAH for an E-5 with dependents at each ZIP, times the benefit level and the rate of pursuit; the online-only row starts from VA’s $1,198 maximum instead. VA’s GI Bill Comparison Tool can show a different housing figure for some ZIPs, as the Post-9/11 guide explains. The MGIB-AD column is a single table lookup.

To compare over a school year, you have to pick a number of months, which is an assumption and not a VA rule. The calculator’s default is 9 months in school. Over 9 months, the housing allowance adds up to $16,254.00 at Fort Bragg, $35,775.00 in San Diego and $10,782.00 online, so the Post-9/11 yearly totals are $29,254.00, $67,683.34 and $42,690.34. Nine months of full-time MGIB-AD at the 3-year rate is $23,409.00, and nine months at 75% is $17,556.75. These are estimates, not payments of record. The two totals aren’t like for like, because the Post-9/11 figure includes tuition VA sends to the school, while the MGIB-AD amount arrives as cash to you and has to cover tuition too. VA prorates the first and last months, so an actual first payment can differ.

The refund (up to $1,200) and the 48-month limit

VA’s Montgomery GI Bill page describes a contribution refund for a veteran with one qualifying period of active duty who served less than 56 months and decides to use the Post-9/11 GI Bill: once that Post-9/11 entitlement is used up, VA says it refunds part or all of the MGIB-AD contributions, up to a maximum of $1,200. For that group VA says generally only one of the two programs can be used, and the maximum Post-9/11 entitlement is 36 months. For a veteran who served 56 months or more in one qualifying period, VA says up to 48 months of combined benefits may be possible. Who gets a refund, and how much, is VA’s determination.

Federal law caps combined use. Under 38 U.S.C. 3695, the total period of assistance across two or more programs, including Chapters 30 and 33, can’t exceed 48 months (or the part-time equivalent). Under 38 U.S.C. 3013, MGIB-AD entitlement is generally up to 36 months, and some people get fewer. VA’s page says up to 48 months across VA education benefits, not counting Veteran Readiness and Employment benefits, and that many people can use only 36 months. A veteran with two qualifying periods, one for each program, may be able to use both after the Supreme Court’s April 16, 2024, Rudisill decision; VA’s page, updated October 21, 2026, says veterans affected by the Rudisill or Perkins decisions no longer have to waive MGIB-AD to use Post-9/11 benefits, and that VA is updating its systems to automate the reviews. VA applies that decision. Our calculator doesn’t compute it.

Next step

Put your days of service, school type, tuition, school ZIP and credits into the GI Bill calculator to see the Post-9/11 figures for your own case, and use VA’s rate pages for the MGIB-AD table. To see how a ZIP becomes a housing area, read BAH 2026 explained.

This is general information, not legal, tax or financial advice. To ask which program applies to you, contact VA’s education office or a school certifying official.