Day of the Week Calculator
Find out what day of the week any date falls on, plus that month's weekday breakdown and future years the same date repeats on.
July 5, 2026 is a
Sunday
Summary
July 5, 2026 falls on a Sunday. It's day 186 of 2026 (179 days remaining in the year), in ISO week 27.
Day of Year
186
ISO Week
27
Weekend?
Yes
How many of each weekday this month has
What is a Day of the Week Calculator?
A day-of-the-week calculator determines which weekday any calendar date falls on — whether it's a historical date, today, or a date far in the future. This is possible because the Gregorian calendar is fully deterministic: given a year, month, and day, the weekday follows mathematically from a repeating 400-year cycle, with no ambiguity or exceptions.
Beyond the weekday itself, this calculator shows how many times each day of the week occurs in that month (useful for scheduling recurring events like "every Tuesday"), and lists which future years the exact same month and day will fall on the same weekday again.
When July 5's Weekday Repeats
Because of the leap year cycle, July 5 doesn't fall on the same weekday every year — here's when it does over the next 12 years.
| Year | Day of Week | Same as 2026? |
|---|---|---|
| 2027 | Monday | No |
| 2028 | Wednesday | No |
| 2029 | Thursday | No |
| 2030 | Friday | No |
| 2031 | Saturday | No |
| 2032 | Monday | No |
| 2033 | Tuesday | No |
| 2034 | Wednesday | No |
| 2035 | Thursday | No |
| 2036 | Saturday | No |
| 2037 | Sunday | Yes |
| 2038 | Monday | No |
How the Weekday Is Calculated
Algorithms like Zeller's congruence compute the day of the week directly from the year, month, and day using modular arithmetic, without needing to count forward day-by-day from a known reference date. The key insight is that the Gregorian calendar repeats its weekday pattern every 400 years exactly — because 400 years contain exactly 146,097 days, which is evenly divisible by 7.
Why a Date's Weekday Shifts Most Years
A regular (365-day) year is exactly 52 weeks plus 1 day, so a given date's weekday normally advances by one each year — if your birthday falls on a Monday this year, it lands on Tuesday next year. Leap years (366 days = 52 weeks + 2 days) cause the weekday to jump forward by two instead of one for dates after February 29, which is why the "same weekday" table above doesn't follow a perfectly even pattern.
The 28-Year (and 400-Year) Repeat Cycle
In the old Julian calendar, weekdays repeated on an exact 28-year cycle. The Gregorian calendar's leap year exceptions (century years not divisible by 400 skip the leap day) break that clean 28-year pattern slightly, but the full pattern still repeats exactly every 400 years — which is also the length of the Gregorian calendar's leap year cycle.
Practical Uses
Knowing a date's weekday is useful for verifying historical records, planning recurring events, checking whether a deadline lands on a weekend (and needs to shift to the next business day), and settling casual questions like "what day of the week was I born on?"
Example — Your Current Input
July 5, 2026 falls on a Sunday. It's day 186 of 2026 (179 days remaining in the year), in ISO week 27.
Additional Example — A Historical Date
July 4, 1776 — the date the U.S. Declaration of Independence was adopted — fell on a Thursday. Working this out required extending the (Gregorian-equivalent) calendar backward using the same modular arithmetic used for future dates, since the weekday-determination rules are fully reversible in both directions.
About This Parameter
- Date
- Any calendar date, in the past or future. The calculator works identically regardless of how far from today the date is.
Frequently Asked Questions
Does this work for dates before the Gregorian calendar was adopted?
This calculator projects the modern Gregorian calendar backward indefinitely (the "proleptic Gregorian calendar"), which is the standard convention for software date calculations. Historically, many countries actually used the Julian calendar before switching to Gregorian at different dates between the 1500s and 1900s, so real historical weekdays before a country's specific switchover date may differ from this calculator's proleptic result.
Why does a birthday sometimes fall on the same weekday two years running?
This happens around leap years for birthdays in January or February. Since the leap day (February 29) falls before those dates in the calendar year, the extra day doesn't affect the weekday shift for a birthday earlier in the year — so occasionally two consecutive years land on the same weekday instead of advancing by one as usual.
How many Fridays does a typical month have?
Most months have exactly four occurrences of each weekday, but any month with 29–31 days will have five occurrences of one to three particular weekdays, depending on which day the month starts on — the chart above shows the exact breakdown for your selected month.
Is there a shortcut to figure out the weekday in my head?
Yes — a well-known trick nicknamed the "doomsday rule" identifies one "anchor" weekday per year (the "doomsday") that several easy-to-remember dates always fall on (like 4/4, 6/6, 8/8, 10/10, and 12/12), then counts forward or backward from the nearest one to find any other date's weekday.