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Today, 12 October 2026, is day 285 of the year; 80 days remain.
The day of the year (or ordinal date) numbers each day from 1 on 1 January to 365 (or 366 in a leap year) on 31 December. It's used in science, computing, logistics and agriculture as a compact way to reference a date, and it instantly tells you how far through the year you are. This tool gives the day number for any date and the days left until year end.
Enter a date, and its day-of-year number and the remaining days appear immediately.
Day of the Year Calculator: step-by-step worked example
- Date
- October 12, 2026
- 1
Days since 1 January
Difference = Date − 1 January
October 12, 2026 − January 1, 2026 = 284 days
- 2
Day of the year
Day number = Difference + 1 (1 Jan = day 1)
284 + 1 = 285
- 3
Year length and days left
Left = Days in year (365/366) − Day number
365 − 285 = 80 days
- 4
Share of the year elapsed
Share = Day number ÷ Days in year × 100
285 ÷ 365 × 100 = 78.0822%
- 5
ISO week and weekday
Weeks start on Monday; week 1 contains the first Thursday
= Week 42 · Monday
- Elapsed (incl. today)285 days78.1%
- Left80 days21.9%
- 1 JanuaryJanuary 1, 2026
- Selected dateOctober 12, 2026
- 31 DecemberDecember 31, 2026
Good to know: 1 January is day 1. In leap years (such as 2028) every date after 28 February shifts by one. The day-of-year number is often called the "Julian date" in manufacturing lot codes.
Day of the Year Calculator — how it works
How it's counted
The day of the year is the count of days from 1 January (which is day 1) up to and including your date. 31 December is day 365 in a normal year and day 366 in a leap year. The tool also shows the days remaining until 31 December.
Leap year effect
From 1 March onward, a leap year's day numbers are one higher than a normal year's, because 29 February (day 60) is inserted. So 1 March is day 60 in a normal year but day 61 in a leap year — worth remembering when comparing dates across years.
Common uses
- Science and data: Julian-style day numbering in astronomy, meteorology and logging.
- Computing: the "day of year" field in date formats and systems.
- Agriculture: growing-degree-day and planting schedules.
- Business: tracking progress through a fiscal or calendar year.
For counting between two arbitrary dates, a days-between-dates calculator is the companion tool.
Worked example
1 March 2026 is day 60 of the year: 31 days in January plus 28 in February (2026 is not a leap year) plus 1 = 60, with 305 days remaining until year end. In a leap year the same 1 March would be day 61, because 29 February adds a day before it. Knowing you're on day 60 of 365 tells you at a glance that about 16% of the year has passed — a quick sense of pace that a calendar date alone doesn't give.
Day-of-year numbers by month in 2026
| Month | Days | First day | Last day |
|---|---|---|---|
| January | 31 | 1 | 31 |
| February | 28 | 32 | 59 |
| March | 31 | 60 | 90 |
| April | 30 | 91 | 120 |
| May | 31 | 121 | 151 |
| June | 30 | 152 | 181 |
| July | 31 | 182 | 212 |
| August | 31 | 213 | 243 |
| September | 30 | 244 | 273 |
| October | 31 | 274 | 304 |
| November | 30 | 305 | 334 |
| December | 31 | 335 | 365 |
Frequently asked questions
How is the day of the year calculated?+
Count the days from 1 January (day 1) up to and including your date. The tool returns the ordinal day number and the days remaining until 31 December.
What is the day of the year for a date?+
For example, 1 March 2026 is day 60 (31 + 28 + 1). The last day, 31 December, is day 365 in a normal year and day 366 in a leap year.
How do leap years affect the day number?+
From 1 March onward, leap-year day numbers are one higher because 29 February (day 60) is inserted. So 1 March is day 60 normally but day 61 in a leap year.
What is an ordinal date?+
An ordinal date expresses a date as the year plus the day-of-year number (e.g. 2026-060 for 1 March 2026). It's a compact format used in science and computing.
How many days are left in the year?+
The tool shows the days remaining until 31 December alongside the day number. On day 60 of a 365-day year, 305 days remain.
Where is the day-of-year number used?+
In astronomy and meteorology (Julian-style day counts), computing date formats, agriculture (growing-degree days) and tracking progress through a fiscal year.
About this page
- Publisher:
- Kalkoro — Teknolojig Bilişim Teknolojileri A.Ş., İstanbul
- Written by:
- Ahmet Tur — Editor (Math, date & time, unit conversion, physics & chemistry, everyday tools)
- Reviewed by:
- Kübra Yıldız — Editor
Parameters come from official sources; the last update date is shown at the bottom of the page.
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