Days left until your ETS date, the last duty day once terminal leave comes off the end, and the 365, 180, 120 and 90 day marks in front of it. Everything is worked out in this page.
ETS stands for Expiration of Term of Service. It is the date on which the enlistment contract you signed runs out, and it is the anchor every other separation date hangs off. Two things about it catch people out. The first is that the ETS date is not automatically the last day you are at work, because terminal leave sits between those two dates. The second is that a service member usually stops reporting several weeks before the calendar says the contract ends, which makes the number people actually want the last duty day rather than the days to ETS.
Terminal leave is ordinary accrued leave taken at the end of a term instead of being cashed out, and it runs up to and including the ETS date. So the arithmetic this page does is simple and it is stated on every card: last duty day equals the ETS date minus the number of terminal leave days, and the leave itself covers the days after that, ending on the ETS date. Thirty days of leave against an ETS of the 22nd puts the last duty day on the 23rd of the previous month.
The services use different letters for the same idea. The Army and the Air Force generally say ETS, Expiration of Term of Service. The Navy and the Coast Guard generally say EAOS, End of Active Obligated Service. The Marine Corps generally says EAS, End of Active Service. They all name the day a term of service runs out, so the arithmetic on this page applies to any of them: put the date in and the counting is identical. What they are not is the same thing as your separation date, your date of discharge or the end of your total military service obligation, which can each sit somewhere else. If the paperwork in front of you uses two of these terms and they disagree, that is a question for your S1, not for a calculator.
Terminal leave is leave you have already accrued, taken in one block at the end of your term. You are still on active duty while you are on it, which is why it ends on the ETS date rather than after it. The practical effect is that your last day of duty arrives earlier than your ETS date by however many days of leave you take, and that earlier date is the one worth planning a move, a start date or a lease around.
This page takes the number of leave days as your input rather than working it out for you, on purpose. How much leave you have, how much of it you may take terminally, whether any of it is sold instead, and whether permissive temporary duty is added in front of it are all policy questions with unit level answers. Ask your S1 for the number, then put that number in the box.
If you know the day the contract started and its length, the second input mode adds the term to the start date on the calendar rather than in days, so a four year term starting on 15 June 2021 lands on 15 June 2025 whatever leap years fall in between. Then there is a convention to pick. Some paperwork records the end of an N year term as that anniversary date, and some records it as the day before, on the reasoning that the first day of service was already day one of the term. The two answers are exactly one day apart, this page will show you either, and the correct one for you is whichever your contract says. If you have the actual date on paper, use the first input mode and skip the question entirely.
One more edge case gets handled quietly. A term that starts on the 31st of a month and ends in a month with 30 days, or on 29 February in a year that has no 29 February, is pulled back to the last day of the target month, and the page tells you when it has done that.
Days until ETS is the plain difference between two calendar days: the number of nights between the day you are counting from and the ETS date. D-30 means thirty days before the day, D-Day is the day itself, and D+30 is thirty days after. The milestone marks use the same plain arithmetic, so the 90 day mark is exactly ninety days before the ETS date and nothing is shifted by a counting convention.
Every figure here comes from arithmetic on the year, month and day you typed. Nothing is converted to or from UTC at any point, which is the usual source of a countdown that is a day out for readers stationed east or west of whoever built it. The day the page counts from is read once from your device clock as a local calendar date, and you can override it in the field above to check any pair of dates without touching your clock.
Free, no sign up, and your dates never leave your browser. Nothing is uploaded and nothing is stored on a server: what you type lives in this page and in the address bar of this tab, which is also how the share link works.
This page is one of a small set of single purpose tools that run entirely in the browser with no account and no server side storage. One of the others counts the days to any date with the counting rule made explicit, one converts a grade point average from a 4.5 or 4.3 scale to the US 4.0 scale, and one checks which AI crawlers a robots.txt file currently lets in.