How to Convert Weeks to Days

To convert weeks to days, multiply the number of weeks by 7, because one calendar week always has exactly 7 days: 3 weeks is 21 days, 10 weeks is 70 days, and 52 weeks is 364 days, one day short of a full year. The only trap is the five-day workweek, which is 5 working days, not 7 calendar days. Convert any time span instantly with our free unit converter.

The Formula: Weeks Times 7, Always

The formula for converting weeks to days is days = weeks times 7, and it never changes, because a calendar week is defined as exactly 7 days in every modern calendar system, from the Gregorian calendar to the ISO week-date system. One week is 7 days, two weeks is 14 days, five weeks is 35 days, and twenty weeks is 140 days, all by the same single multiplication. The 7-day week is one of the oldest unbroken time cycles in human history, running continuously since Babylonian times, which is why no calendar reform has ever disturbed it: unlike months, which vary, weeks are perfectly uniform. The reverse formula is weeks = days divided by 7, so 100 days divided by 7 is 14 weeks with 2 days left over, written as 14 weeks and 2 days. That remainder matters whenever you convert a day count back into weeks, because most real day counts are not exact multiples of 7. A useful check is that your day answer must always be larger than your week figure, roughly seven times larger: if you multiplied and got a smaller number, you divided by mistake. For a single value without the arithmetic, the free unit converter gives the figure at once, and our minutes to hours converter handles the smaller time step that often appears beside week conversions in schedules and timesheets.

Weeks to Days Conversion Chart

A short weeks to days chart covers most everyday values, and the first few rows are worth memorizing. One week is 7 days, two weeks is 14 days, three weeks is 21 days, four weeks is 28 days, five weeks is 35 days, six weeks is 42 days, eight weeks is 56 days, ten weeks is 70 days, and twelve weeks is 84 days. Longer spans follow the same pattern: twenty-six weeks is 182 days, which is almost exactly half a year, and fifty-two weeks is 364 days, one day short of a common year and two short of a leap year. That last row surprises people, because a year is often described as 52 weeks, yet 52 weeks is not a year: the missing day or two is why calendars drift and why a fixed weekday, like your birthday, moves forward one weekday each year. So how many days are in 3 weeks? Twenty-one, exactly, and the same row answers the most common follow-up: a 3-week vacation is 21 calendar days, even if only 15 of them are working days. For values between chart rows, multiply directly rather than estimating between rows, because a one-week error is a full seven days. Our days to hours guide continues the chain downward, and the minutes to seconds guide goes smaller still for timesheet math.

The Workweek Trap: 5 Working Days Is Not 7 Days

The single biggest source of wrong week-to-day answers is the workweek. A workweek has 5 working days, Monday through Friday, while a calendar week has 7 days, so two workweeks is 10 working days but 14 calendar days, and confusing the two throws a deadline off by four days. The phrase to watch for is business days: a task due in 10 business days is due two calendar weeks later, not ten days later, and a delivery promised in 2 weeks arrives in 14 calendar days, which may include two weekends. Project plans are where this bites hardest. A manager who says a job takes 6 weeks usually means 6 calendar weeks, which is 42 calendar days but only 30 working days, and a team that budgets 30 days of effort for it will finish a week late if weekends were never counted. The defense is to state the unit every time: write 14 calendar days or 10 working days, never just 2 weeks, when a deadline matters. Holiday weeks make it worse, since a week containing a public holiday has only 4 working days, so a 3-week project spanning a holiday week is 14 working days, not 15. When the schedule involves timestamps rather than dates, our Unix timestamp converter translates between human dates and machine time, and the hours-and-minutes Excel guide shows how to add work time without losing the weekends.

Pregnancy Weeks, Sprints, and Subscriptions: Where This Conversion Lives

Three everyday domains run on week-to-day math. Pregnancy is counted in weeks, and the standard 40-week pregnancy is 280 days from the last menstrual period, which is why week 20 is called the halfway point at 140 days, and why a baby born at 37 weeks is 259 days, considered early term rather than premature. Software teams plan in sprints, and a 2-week sprint is 14 calendar days but 10 working days, so a team promising 3 sprints of work is promising 42 calendar days, and a stakeholder who hears 30 days will be disappointed by nearly two weeks. Subscription and billing cycles use a different week: a 4-week billing cycle is 28 days, which is shorter than every calendar month except February, so a service billed every 4 weeks charges 13 times a year, not 12, and that thirteenth charge surprises customers every year. Fitness programs use the same math: a 12-week program is 84 days, and a 90-day challenge is 12 weeks and 6 days, not 13 weeks. The pattern across all four is the same: weeks are exact, but what people mean by a week changes with context, so name the context before you multiply. For the reverse direction, our days to hours guide covers the next step down, and the hours to seconds guide handles the finest timesheet splits.

Fractional Weeks and the Remainder Problem

Real schedules rarely land on whole weeks, so fractional weeks need a rule. Multiply the decimal directly: 2.5 weeks is 17.5 days, 0.5 weeks is 3.5 days, and 1.25 weeks is 8.75 days, which is 8 days and 18 hours. The question is what to do with the fraction. For travel and bookings, round up: a hotel stay of 2.5 weeks needs 18 nights booked, not 17, because half a day still needs a bed. For project estimates, keep the decimal until the final step, because rounding each intermediate week compounds: rounding 2.5 weeks to 3 weeks, then multiplying by a daily rate, overstates the cost by two full days. Going the other way, divide and keep the remainder as days, not as a decimal: 100 days is 14 weeks and 2 days, which is far more useful than 14.29 weeks, because nobody schedules 0.29 of a week. A special case is the half-week: 3.5 days is the answer to half a week, and it appears in shift patterns, where a worker on a half-week rotation works 3 or 4 days alternating, and in medication schedules, where every-3.5-day dosing is really twice a week. When the conversion feeds a spreadsheet, the Excel time guide shows how to keep fractional days from silently rounding, and the Unix timestamp converter gives exact day counts between two dates when the stakes are high.

Weeks to Days in Excel and Google Sheets

A weeks to days in Excel conversion is one formula: put the weeks in cell A1 and use =A1*7 in B1, and the result is days. For a whole column of week values, fill the formula down and every row converts at once, which is how project managers turn a sprint plan into a day count in seconds. The reverse is =A1/7, and to show it as whole weeks plus leftover days, use =INT(A1/7)&" weeks, "&MOD(A1,7)&" days", which turns 100 into the readable 14 weeks, 2 days. Date arithmetic works the same way: if a project starts on the date in A1 and runs 6 weeks, its end date is =A1+6*7, or =A1+42, and formatting the result as a date shows the deadline directly. Google Sheets uses identical formulas, so the same sheet works in both apps. Two formatting traps to avoid: first, a cell formatted as a date will display a day count like 42 as a calendar date in 1900, so format day-count cells as plain numbers; second, the WEEKDAY function counts from Sunday or Monday depending on its second argument, so check that setting before using it to find working days inside your week count. For time-of-day math inside those days, the minutes to seconds guide covers the smaller units, and the minutes to hours converter handles the hour step that timesheets usually need next.