Weeks to Days Converter: Decimal and Whole Weeks to Total Days, Hours, Minutes, Reverse Days to Weeks with Remainder

1 week = exactly 7 days. This is the universal definition used in the United States and globally. The 7-day week has ancient origins and is used consistently in all US legal, medical, financial, and cultural contexts. 1 week = 7 days = 168 hours = 10,080 minutes = 604,800 seconds. There is no ambiguity, no rounding, and no exception: one week is always seven calendar days. This contrasts with months (28, 29, 30, or 31 days), quarters (approximately 91 days), and years (365 or 366 days), which all vary in day count.

2 weeks = 14 days = 336 hours = 20,160 minutes. A two-week period is one of the most common time spans in American professional life. Biweekly payroll (the most popular payroll frequency in the US, used by about 43% of employers according to the American Payroll Association) runs every 14 days. A “two-week notice” for resignations means exactly 14 calendar days. Many prescription medications specify a 2-week supply as the standard initial fill. The standard US vacation award for new employees is often “10 working days” (2 standard work weeks = 14 calendar days). Travel visa-free stays in many countries are limited to 14 days for short visits.

4 weeks = 28 days = 672 hours = 40,320 minutes. Four weeks is the only weekly count that can equal a complete calendar month, but only for February in a non-leap year. All other months have 29, 30, or 31 days, meaning they are longer than 4 weeks. This is why “monthly” and “every 4 weeks” produce different schedules over time: 12 months per year but 13 four-week periods per year (52 weeks / 4 = 13). Landlords who advertise rent as “$1,200 per month” mean approximately $1,200 per 30-31 day period. A “28-day billing cycle” (used by some credit card issuers) produces 13 billing cycles per year, which is why those cards send 13 statements annually while calendar-month cards send 12.

6 weeks = 42 days = 1,008 hours = 60,480 minutes. Six weeks is a clinically significant period in several US healthcare contexts. Postpartum care guidelines from ACOG typically schedule a follow-up visit at 6 weeks after delivery (42 days postpartum). Many short-term disability plans have a 6-week (42-day) maximum benefit period for uncomplicated vaginal deliveries and 8-week periods for C-sections. Workers’ compensation healing periods for many minor injuries are estimated at 4 to 6 weeks (28 to 42 days) in medical impairment rating guidelines. In fitness programming, 6-week training cycles are a common block periodization structure for both strength training and endurance sports.

8 weeks = 56 days = 1,344 hours = 80,640 minutes. Eight weeks is sometimes confused with 60 days in legal and HR contexts. The WARN Act (Worker Adjustment and Retraining Notification Act) requires 60 calendar days advance notice for mass layoffs, which is close to but not equal to 8 weeks (56 days). 60 days = 8 weeks and 4 days. A business plan covering “the first 8 weeks” of a new venture = 56 calendar days. In fitness: many structured beginner programs (Couch-to-5K, starting strength programs) run 8 weeks. In political campaigns: the general election “final stretch” is often described as the last 8 weeks = 56 days before Election Day.

10 weeks = 70 days = 1,680 hours = 100,800 minutes. Ten weeks is the standard academic quarter duration at universities using the quarter system (approximately 35% of US universities, including UC Berkeley, UCLA, Northwestern, and the University of Washington). A 10-week quarter gives students 70 calendar days per term for instruction plus finals week. Many intensive professional training programs (coding bootcamps, real estate licensing courses, short-term certificate programs) are structured in 10-week cohorts. FDA New Drug Application (NDA) review periods are tracked in weeks, with a 10-month standard review period containing approximately 43 weeks.

12 weeks = 84 days = 2,016 hours = 120,960 minutes. Twelve weeks is the federally mandated maximum FMLA leave period under the Family and Medical Leave Act (29 C.F.R. Part 825). 84 days divides evenly by 7 (84/7 = 12.0000 exactly), making it a clean conversion. In pregnancy: 12 weeks marks the end of the first trimester (84 days from LMP). In fitness: a 12-week body transformation or marathon training program is one of the most common program lengths. In business lending: 90-day business loans are close to but not exactly 12 weeks (90 days = 12 weeks 6 days). At $50,000 borrowed over 12 weeks at 1% weekly interest, each week’s interest compounds on the prior balance.

26 weeks = 182 days = 4,368 hours = 262,080 minutes. Twenty-six weeks is exactly half of a 52-week year in weekly terms, and 182 days is exactly half of a 364-day year (26 x 7 = 182, and 2 x 182 = 364). This makes 26 weeks the cleanest “6-month equivalent” from a weekly math standpoint, even though 6 calendar months contain 181, 182, 183, or 184 days depending on which months. In payroll: 26 biweekly pay periods make up a year, so week 26 marks the halfway point through the payroll calendar. In healthcare: extended short-term disability policies often have 26-week maximum benefit periods. In sports: major league seasons often run close to 26 weeks (the NBA regular season is 29 weeks, MLB about 26 weeks from Opening Day to the end of the regular season).

40 weeks = 280 days = 6,720 hours = 403,200 minutes. Forty weeks is the standard gestational period for a full-term human pregnancy, measured from the first day of the last menstrual period (LMP). 280 days from LMP is the estimated due date (EDD) used by OB-GYNs and midwives in the United States. The American College of Obstetricians and Gynecologists defines full-term as 39 weeks 0 days through 40 weeks 6 days, meaning delivery between 273 and 279 days from LMP is considered full-term. Early term is 37 to 38 weeks 6 days (259-272 days). Preterm is before 37 weeks (before 259 days). Post-term is after 42 weeks (after 294 days). Naegele’s Rule for calculating due dates: first day of LMP, add 1 year, subtract 3 months, add 7 days. This approximates 40 weeks (280 days) from LMP.

52 weeks = 364 days exactly, NOT 365. This is one of the most important and consistently misunderstood facts in calendar math. A standard calendar year has 365 days (366 in a leap year). Since 52 x 7 = 364, there is always 1 extra day in a standard year (and 2 extra days in a leap year) beyond the 52-week count. This 1-day surplus is why the same calendar date falls on a different day of the week each year: the extra day shifts the entire calendar forward by one weekday. For biweekly payroll: 52 weeks / 2 = 26 biweekly periods = 364 days, leaving 1 or 2 days at year-end that create a 27th partial pay period in some years. For annual subscription renewals dated from a week number rather than a calendar date: a “52-week renewal” comes 1 day short of a calendar year.

3 weeks = 21 days = 504 hours = 30,240 minutes. Twenty-one days appears frequently in contract law, immigration law, and healthcare. Under the ADEA (Age Discrimination in Employment Act), employees over 40 must be given 21 days to consider a severance agreement that includes a waiver of ADEA claims. Under ERISA, group health plans must provide 21 days notice for certain plan changes. In immigration: J-1 visa holders have 21 days after completing their program to depart or transfer status. In health: many pharmaceutical drug trials include 21-day observation windows. In business: “net 21” payment terms require invoice payment within 21 calendar days of the invoice date.

1 week = 168 hours. The calculation: 7 days x 24 hours per day = 168 hours. This is the total available time in a week. A 40-hour work week (the standard under FLSA) represents 40/168 = 23.8% of all available hours. An 8-hour sleep schedule uses 56 hours per week (8 x 7 = 56), or 33.3% of available time. The book “168 Hours” by time management author Laura Vanderkam uses 168 as the foundational number for weekly time budgeting: 40 hours working + 56 hours sleeping = 96 hours, leaving 72 hours (42.9% of the week) for everything else. 168 hours = 10,080 minutes = 604,800 seconds exactly.

1 week = 10,080 minutes. The calculation: 7 days x 24 hours x 60 minutes = 10,080. Memorizing 10,080 as the minutes-per-week is useful for productivity planning and scheduling at a minute level. A typical 40-hour work week = 2,400 minutes of work time out of 10,080 total minutes available (23.8%). A 30-minute daily exercise habit = 210 minutes per week = 2.1% of the week. The US average of 5.5 hours of leisure time per day per BLS American Time Use Survey = 38.5 hours per week = 2,310 minutes = 23% of the weekly 10,080-minute budget. 10,080 minutes = 604,800 seconds exactly.

2.5 weeks = 17.5 days = 420 hours = 25,200 minutes. Two and a half weeks does not produce a whole number of days, which is why professional contexts almost always use whole week counts for scheduling. However, medical paperwork, leave calculations, and insurance claims sometimes produce fractional week counts when the benefit period begins mid-week. 2.5 weeks = 17 full days and 12 hours. For scheduling purposes, 2.5 weeks is typically rounded either to 17 days (if rounding down to full calendar days) or 18 days (if rounding up to include the partial day). In hours: 2.5 x 168 = 420 hours exactly.

30 days = 4.2857 weeks = 4 weeks and 2 days. The calculation: 30/7 = 4.285714 (repeating). Thirty days is a common contract term (net-30 payment, 30-day notice to vacate, 30-day return policies), but it is not a clean number of weeks. Thirty days spans 4 weeks and 2 extra days, meaning it crosses over into a fifth calendar week. In contrast: 28 days = exactly 4 weeks (4.0000). 35 days = exactly 5 weeks (5.0000). 30 days sits between these two anchors. For FMLA purposes, 30 calendar days of intermittent leave = 30/7 = 4.29 FMLA weeks used out of the 12-week (84-day) entitlement.

100 days = 14.2857 weeks = 14 weeks and 2 days. The calculation: 100/7 = 14.285714 (repeating). The “first 100 days” of a presidency is a political tradition rooted in FDR’s first 100 days in 1933 but used to benchmark all subsequent US presidents. 100 calendar days equals 14 weeks and 2 extra days. In a year starting January 20 (inauguration day), the 100th day falls on April 29 or April 30 depending on leap year. In startup culture, “100-day plans” are common for new executives joining organizations. 100 days = 14.29 weeks = 2,400 hours = 144,000 minutes.