Sobriety date calculator
Count completed sober days and the inclusive calendar day, track anniversaries, measure progress toward a personal goal and estimate optional spending avoided.
How sober days are counted
Completed full days is the number of midnight-to-midnight intervals after the start date. Inclusive calendar day treats the start date as day 1, so it is one greater. Showing both avoids ambiguity between common counting conventions.
Calendar elapsed time is expressed as complete years, then complete months, then remaining days. Month and year additions clamp to the last valid day when necessary; for example, a February 29 start reaches its one-year anniversary on February 28 in a non-leap year.
Formulas
completed days = calculate-through date − start date
inclusive day = completed days + 1
estimated savings = completed days × former daily spending
goal progress = elapsed days ÷ total goal days × 100%, limited to 0%–100%.
Checked examples
| Start | Calculate through | Expected completed days |
|---|---|---|
| January 1 | January 1 | 0 completed; calendar day 1 |
| January 1 | January 8 | 7 completed; 1 week |
| February 28, 2024 | March 1, 2024 | 2 days |
| February 29, 2024 | February 28, 2025 | 365 days; 1 calendar year |
| January 31, 2025 | February 28, 2025 | 28 days; 1 calendar month |
| January 1 | Day 90 | 90 completed days |
Frequently asked questions
Is the sobriety date day 0 or day 1?
Both conventions exist. This calculator reports completed 24-hour date intervals and the inclusive calendar-day number separately.
Does the calculator store my sobriety date?
No. The calculation runs locally on the page and does not create an account or progress record.
Are savings exact?
No. Savings and units avoided are simple estimates based on the constant daily values you enter. They do not account for changing habits or replacement spending.
Can I use a future goal?
Yes. Add a goal date after the start date to see elapsed percentage, completed days and remaining days. Progress stops at 100% once the date is reached.
Related tools: Date Calculator, Age Calculator, Blood Alcohol Calculator and Time Calculator.