How many days has it been since a date?
How many days since New Year’s, since you moved, since you met, since your last cigarette — every “days since” question counts from a date up to today. The answer grows by one every morning, so there is no point looking up a ready-made number. Here are methods that give you the answer in a minute, with examples worked out for October 29, 2026.
Method 1. Day-of-year numbers
If the date and today are in the same year, a single subtraction does it: today’s day number − the date’s day number. Some useful starting points:
| Since | Day of year | In a leap year |
|---|---|---|
| January 1 (New Year’s Day) | 1 | 1 |
| March 1 | 60 | 61 |
| June 1 | 152 | 153 |
| June 21 (summer solstice, roughly) | 172 | 173 |
| July 4 | 185 | 186 |
| September 1 | 244 | 245 |
Any date’s number = the number of the 1st of its month + (the day − 1). The full month-by-month table is in how many days until a date.
Worked examples for October 29, 2026
October 29 is day 302 of the year (274 + 28). So:
| Days since | Math | Answer |
|---|---|---|
| January 1, 2026 | 302 − 1 | 301 days |
| June 1, 2026 | 302 − 152 | 150 days |
| the Fourth of July | 302 − 185 | 117 days |
| Labor Day (September 7, 2026) | 302 − 250 | 52 days |
| Christmas 2025 | 7 + 301 | 308 days |
| January 1, 2025 | 365 + 301 | 666 days |
For a different day, swap in its number for 302 — the math is the same.
When the date was in an earlier year
Work in three steps: the rest of that first year, whole years, then this year so far.
- The rest of the first year. From the date to January 1 of the next year: 366 − the date’s number (367 − the number in a leap year).
- Whole years. 365 days each, 366 for a leap year. Which years are leap years is in how many days are in a year.
- This year. Today’s day number minus one.
Example: from August 8, 2020 to October 29, 2026. August 8, 2020 is day 221 of a leap year, leaving 367 − 221 = 146 days in that year; 2021 through 2025 add 365 × 4 + 366 (2024) = 1,826; 2026 adds 301. Total: 146 + 1,826 + 301 = 2,273 days.
When neither date is today, use the general method in how to count the days between two dates — it also covers whether to include both end dates.
Method 2. Excel or Google Sheets
Put the date in A1 and a formula next to it:
=TODAY()-A1— days since the date (format the formula cell as a number, or the sheet will show a date);=DATEDIF(A1,TODAY(),"m")— whole months;"y"— whole years;=DATEDIF(A1,TODAY(),"md")— days left over after whole months; combined with"y"and"ym"you get “2 years, 3 months, 5 days.”
The formula recalculates every time you open the file, so you write it once and it always answers for today. It works the same in the Google Sheets app on your phone.
Bonus: what weekday it was
Once you know how many days have passed, the weekday is easy: divide by 7 and look at the remainder. 666 days is 95 weeks and 1 day, so January 1, 2025 fell one weekday earlier than October 29, 2026 — a Wednesday versus a Thursday.
A “days since” counter that keeps itself up to date
Counting once takes a minute. If you want the number all the time — days together, days sober or smoke-free, days since you started a new job — a counter that updates itself is easier. Think of the “days since last incident” sign, but on your phone.
In Temfy: Countdown Days & Widget you set a date and choose “since”: the app shows how long it has been in days, hours, minutes and seconds, and a Home Screen widget keeps the number in sight. Count-ups get milestones — 100, 500 and 1,000 days and anniversaries. Free for iPhone and Android, no sign-up needed.
Let the days count themselves
Temfy: Countdown Days & Widget shows how long until an event and how long since a big day, down to the second. Widgets, reminders, habit streaks and milestones. Free for iPhone and Android.