Seconds to Weeks Converter

Convert seconds to weeks instantly. Enter any value — the result updates as you type. 1 week = exactly 604,800 seconds (7 × 86,400). This constant is 604,800 = 2⁷ × 3³ × 5² × 7 — the day's 96 divisors multiplied by the week's factor of 7, giving a total of 192 divisors. Every clean sub-week interval divides 604,800 exactly. Use the swap button to reverse.

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SecondsWeeks
10.00000165
600.00009921
3,6000.00595238
86,4000.14285714
302,4000.5
604,8001
1,209,6002
2,629,7464.348125
24,192,00040
31,449,60052
31,556,95252.1775

How to Convert Seconds to Weeks

Divide seconds by 604,800 to get weeks. Multiply weeks by 604,800 to get seconds. This constant is exact: 7 days × 86,400 s/day = 604,800 s/week. The formula:

Weeks = Seconds ÷ 604,800 Seconds = Weeks × 604,800 1 week = 7 × 86,400 = 604,800 s  |  604,800 = 2⁷ × 3³ × 5² × 7 192 divisors — more than any other common time constant in this series

The number 604,800 = 2⁷ × 3³ × 5² × 7 has 192 divisors — (7+1)(3+1)(2+1)(1+1) = 8×4×3×2 = 192. This is the daily 86,400 (96 divisors) multiplied by 7, inheriting all of the day's clean fractions while adding weekly periodicity. Every duration that divides a day also divides a week. This is why weekly schedules, therapy intervals, training cycles, and security tokens all express naturally in multiples of 604,800 seconds.

Conversion table (Seconds ÷ 604,800 = Weeks)

1 s = 0.00000165 weeks (1/604,800) 60 s = 0.00009921 weeks (1 minute) 3,600 s = 0.00595238 weeks (1 hour = 1/168 week) 86,400 s = 0.14285714 weeks (1 day = 1/7 week) 302,400 s = 0.50000000 weeks (3.5 days = half week, EXACT) 604,800 s = 1.00000000 weeks (1 week, EXACT) 1,209,600 s = 2.00000000 weeks (1 fortnight, EXACT) 2,629,746 s = 4.34812500 weeks (~1 Gregorian month) 24,192,000 s = 40.0000000 weeks (pregnancy term, EXACT!) 31,449,600 s = 52.0000000 weeks (52-week "year", EXACT) 31,556,952 s = 52.1775000 weeks (1 Gregorian year — NOT 52 weeks!)KEY: 302,400 s = half a week exactly (3.5 days). 24,192,000 s = exactly 40 weeks = standard pregnancy term. 52 weeks = 31,449,600 s ≠ 1 year (gap = 107,352 s = 1.2425 days).

604,800: The Most Divisible Common Time Constant

Comparing divisor counts of major time constants: 86,400 (seconds/day) = 2⁷×3³×5² → 96 divisors 604,800 (seconds/week) = 2⁷×3³×5²×7 → 192 divisors ← MOST 3,600 (seconds/hour) = 2⁴×3²×5² → 36 divisors 60 (seconds/minute) = 2²×3×5 → 12 divisors604,800's key sub-week exact divisions: 1/2 week = 302,400 s (3.5 days — mid-week point) 1/4 week = 151,200 s (1.75 days) 1/7 week = 86,400 s (1 day — exact!) 1/8 week = 75,600 s (21 hours) 1/14 week = 43,200 s (12 hours) 1/21 week = 28,800 s (8 hours — workday!) 1/24 week = 25,200 s (7 hours) 1/28 week = 21,600 s (6 hours) 1/42 week = 14,400 s (4 hours) 1/56 week = 10,800 s (3 hours) 1/84 week = 7,200 s (2 hours) 1/168 week= 3,600 s (1 hour — exact!)Every hour-interval, every shift duration, every day of the week is an exact fraction of 604,800 seconds.

Seconds to Weeks: Pregnancy, Biology and the 40-Week Constant

Full-term pregnancy = exactly 40 weeks = 40 × 604,800 = 24,192,000 seconds. This is one of the most medically significant exact-integer second counts in biology:

Gestational milestones in seconds: Implantation (~1 week): 604,800 s = 1 wk Heartbeat detected (~6 weeks): 3,628,800 s = 6 wk End of first trimester (13wk): 7,862,400 s = 13 wk Anatomy scan (~20 weeks): 12,096,000 s = 20 wk Viability threshold (~24wk): 14,515,200 s = 24 wk Premature birth threshold(37w):22,377,600 s = 37 wk Full term (40 weeks): 24,192,000 s = 40 wk ← EXACT INTEGER Post-term (42 weeks): 25,401,600 s = 42 wkCircaseptan (7-day) biological rhythms: The 7-day week is not arbitrary — humans show ~7-day periodicities in: - Blood pressure rhythms (circaseptan oscillation) - Immune response cycles (post-infection antibody peaks at 7, 14, 21 days) - Organ transplant rejection peaks (7 and 14 days post-transplant) - Cell cycle research protocols (based on 7-day multiples) All these are exact multiples of 604,800 seconds.

Seconds to Weeks: The Year Gap — Why 52 Weeks ≠ 1 Year

52 weeks = 31,449,600 seconds. 1 Gregorian year = 31,556,952 seconds. The gap: 107,352 seconds = 1.2425 days. This matters in payroll, scheduling, and fiscal calendars:

52 weeks in seconds: 52 × 604,800 = 31,449,600 s 1 Gregorian year (s): 31,556,952 s Gap: 107,352 s = 1.2425 daysThis gap causes: - Some years have 53 ISO weeks (roughly every 5–6 years) - Weekly payroll: 52 pay periods/year leaves 1.2425 days unaccounted - Broadcasting: "52-week high/low" ≠ exactly 1 year of trading - Bi-weekly scheduling drifts ~2.485 days/year from calendar alignmentISO week year (ISOWeekYear) vs. Gregorian year: ISOWeekYear has 52 or 53 weeks. 52 × 604,800 = 31,449,600 s (52-week ISO year) 53 × 604,800 = 32,054,400 s (53-week ISO year) Average: (52 + 52 + 52 + 52 + 53) / 5 × 604,800 ≈ 31,536,000 s/yr (Close to the Gregorian mean but still ~20,952 s short per year)

Seconds to Weeks: Computing, Security and the 604,800-Second Token

In web development and API security, 604,800 seconds (1 week) is the single most common token and cache lifetime. Its integer nature makes it ideal for cryptographic computations:

  • Refresh tokens (OAuth 2.0): The de facto standard refresh token lifetime is 604,800 seconds = 1 week. At exactly 604,800, there's no rounding, no off-by-one-second bugs, and the expiry aligns with a full 7-day calendar week
  • HTTP Cache-Control max-age: Cache-Control: max-age=604800 is one of the most commonly deployed cache headers for static assets (images, fonts, CSS). It means "cache for exactly 1 week = 604,800 seconds"
  • SSL/TLS certificate validity periods: Let's Encrypt issues certificates valid for 90 days = 12.857 weeks = 7,776,000 seconds. Historically, 1-year certs = 52.1775 weeks = 31,536,000 s were standard
  • GDPR data retention (weekly granularity): Many GDPR compliance systems set data retention at exact-week multiples: 4 weeks = 2,419,200 s (short-term), 52 weeks = 31,449,600 s (annual), 260 weeks = 157,248,000 s (5 years)
  • Romanian DPA (ANSPDCP) retention: CCTV footage retention: maximum 30 days = 2,592,000 s ≈ 4.286 weeks. Employee attendance records: minimum 50 years = 1,576,800,000 s ≈ 2,608.7 weeks

Seconds to Weeks: Sports Training and Recovery Cycles

Training protocol Seconds Weeks 1 training session (1.5h): 5,400 s = 0.00893 wk Daily training (2hr/day): 10,800 s/day × 7 = 75,600 s/wk Weekly training volume: varies; elite = 100–200km/wk × time/kmKey weekly training constants in seconds: Rest day (24hr): 86,400 s = 1/7 wk (exact) Active recovery (1 week): 604,800 s = 1 wk Microcycle (1 week): 604,800 s (standard training unit) Mesocycle (4 weeks): 2,419,200 s (typical strength block) Macrocycle (16 weeks): 9,676,800 s (competition preparation)Marathon training plan (16 weeks): 9,676,800 s Long run pace: 5:30 min/km = 330 s/km Weekly long run 30km: 9,900 s = 2.75 hours Total long run seconds: 16 × 9,900 = 158,400 s = 0.262 weeksWorld Athletics weekly mileage (Kipchoge level): ~200 km/week at ~3:00 min/km = 180 s/km 200 km × 180 s/km = 36,000 s/week of running = 36,000 / 604,800 = 5.95% of the week spent running

Seconds to Weeks: History at Second Resolution

Event / Period Seconds exact Weeks World War I (1,567 days) 135,388,800 s 223.8571 wk World War II (2,193 days) 189,475,200 s 313.2857 wk Romanian communism 1,324,771,200 s 2190.4286 wk Romania modern state 5,242,320,000 s 8667.8571 wk Marea Unire → today 3,353,616,000 s 5545.0000 wk Post-communism (1989–2025) 1,111,190,400 s 1837.2857 wk Romania in EU (2007–2025) 573,868,800 s 948.8571 wkNotable weekly durations: Apollo 11 mission (8 days 3h 18m): 703,080 s = 1.162 wk Pregnancy full term (40 wk): 24,192,000 s = 40.000 wk (EXACT!) Average human life (75yr): 2,366,820,000 s = 3,913.3 wk

Tips and Recommendations

  • Formula: Weeks = Seconds ÷ 604,800. Seconds = Weeks × 604,800. 604,800 = 7 × 86,400 = 2⁷×3³×5²×7 has 192 divisors — every common scheduling interval divides it exactly
  • In JavaScript: const weeks = seconds / 604800;. Weeks since epoch: Math.floor(Date.now() / 1000 / 604800). Between dates: (dateB - dateA) / (604800 * 1000). Cache header: res.setHeader('Cache-Control', 'max-age=604800')
  • In Python: weeks = seconds / 604800. From timedelta: delta.total_seconds() / 604800. Alternatively: delta.days / 7. One week: datetime.timedelta(weeks=1).total_seconds() == 604800
  • In Excel: =A1/604800. Reverse: =A1*604800. Weeks between dates: =INT((B1-A1)*1440/10080) or simpler =(B1-A1)/7 (if A1,B1 are date values)
  • Key exact values: 302,400 s = 0.5 weeks (half week). 86,400 s = 1/7 week (1 day). 24,192,000 s = 40 weeks (pregnancy). 31,449,600 s = 52 weeks. Always use 604,800 (not 604,801 or ~604,800) — it's exact

Seconds to Weeks — Frequently Asked Questions

How many seconds are in 1 week?

Exactly 604,800 seconds (7 × 86,400 = 604,800). This is an exact integer with 192 divisors — more than any other common time constant. Every clean sub-week duration divides 604,800 exactly.

How many seconds is half a week?

Half a week = 3.5 days = 302,400 seconds exactly (604,800 ÷ 2 = 302,400). Half a week is one of the most precise conversions in scheduling because 302,400 is itself a round number.

How many weeks is a full-term pregnancy in seconds?

Full-term pregnancy = 40 weeks = 40 × 604,800 = 24,192,000 seconds exactly. This is a notable exact integer that arises because pregnancy duration is measured in whole weeks from the start.

Why is 604,800 used for 1-week cache and token lifetimes in web development?

Because 604,800 is an exact integer of seconds, there is no rounding when expressing "1 week" in seconds for HTTP headers (max-age=604800), JWT tokens (exp = now + 604800), or OAuth refresh tokens. Any non-integer would create off-by-one bugs at week boundaries.

Is 52 weeks exactly 1 year in seconds?

No. 52 weeks = 31,449,600 seconds. 1 Gregorian year = 31,556,952 seconds. The gap is 107,352 seconds ≈ 1.2425 days. This is why some years have 53 ISO weeks, and why weekly payroll schedules drift from the calendar year.

How many seconds is a fortnight?

1 fortnight = 2 weeks = 2 × 604,800 = 1,209,600 seconds exactly. The fortnight is commonly used in UK and Australian payroll, benefit payment schedules, and cricket match durations.

How do I convert seconds to weeks in JavaScript?

const weeks = seconds / 604800;. Weeks since Unix epoch: Math.floor(Date.now() / 1000 / 604800). Between two Date objects: (dateB - dateA) / (604800 * 1000).

How do I convert seconds to weeks in Python?

weeks = seconds / 604800. From timedelta: delta.total_seconds() / 604800 or delta.days / 7. Verify: from datetime import timedelta; timedelta(weeks=1).total_seconds() == 604800.

How do I convert seconds to weeks in Excel?

=A1/604800. Reverse: =A1*604800. Weeks between date cells: =(B1-A1)/7 (Excel stores dates as days, so dividing by 7 gives weeks).

How many seconds did World War II last in weeks?

WWII lasted 2,193 days = 189,475,200 seconds = 313.2857 weeks.

What are circaseptan rhythms and why are they measured in multiples of 604,800 seconds?

Circaseptan rhythms are biological cycles with an approximately 7-day period. They appear in blood pressure oscillations, immune response peaks (7, 14, 21 days post-infection), and organ transplant rejection windows. Because they repeat every 604,800 seconds (or multiples of it), medical protocols measuring these cycles naturally use 604,800 as the base unit.

How many weeks is 1 Gregorian month in seconds?

1 mean Gregorian month = 2,629,746 seconds ÷ 604,800 = 4.34812 weeks ≈ 4 weeks and 2.44 days. A calendar month is not an exact number of weeks, which is why monthly billing and weekly scheduling always drift apart.