01. Right Now
The current moment, in both systems, updated live.
02. The Short Version
A clock and a calendar rebuilt from scratch, keeping only what the sky actually dictates. Six facts cover almost all of it.
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The day
10 hours of 100 minutes of 100 seconds. One metric second is 0.864 of an ordinary one. The clock reads 96.2% and 09:62 at the same moment, because they are the same number — the time is the fraction of the day elapsed.
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The year
12 months of exactly 30 days. That is 360, so the leftover 5 days (6 in a leap year) become festival days that sit outside the calendar — those are the wide bars above and below the grid, and they belong to no week.
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The week
5 days — Prim, Seco, Tert, Quad, Quin — three working, two off. Because 360 divides evenly by 5, every date falls on the same weekday every year, forever.
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The start
The year opens at the March equinox — 0° of ecliptic longitude, the zero point astronomers already measure everything else from — rather than at a January chosen for other reasons.
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The year number
HE is the Human Era count: CE + 10,000, so 2026 CE is 12026 HE. It puts the whole of settled human history on one positive scale.
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Month names
Months are numbered, and labeled with the 30° arc of Earth's orbit they span. The zodiac sign beneath is the sky's own name for that same arc. The Gregorian name sits beside it, and Gregorian dates run alongside throughout.
03. Reading the Interface
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C
The Clock
Outer Ring: Legacy hours (12, 18, 0, 6).
Inner Ring: Metric Hours (0–10).
The day's length: the metric day runs from your local midnight to the next, so it always starts at 00:00:00 and ends at 09:99:99. On a daylight-saving changeover the civil day is 23 or 25 hours long and the metric hours stretch or compress to fit it.
Solar Markers: Approximate sunrise/sunset, calibrated for ≈ 40° latitude. Near the equator the drift collapses to almost zero; near the polar circles it becomes extreme. Treat as illustrative, not predictive.
Work / Rest Arcs: Faint shaded bands marking suggested productive hours (≈ 33% – 71% of the metric day, roughly 8 am – 5 pm legacy) and rest hours (≈ 92% – 25%, roughly 10 pm – 6 am). These are cultural defaults, not part of the system itself.
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O
Orbit View
Heliocentric (top-down) view. The four colored arcs are the quarters of the orbit, 90° of ecliptic longitude each. Earth is drawn at its true longitude, so it reaches each marker at the real moment rather than on a day count — it moves faster in January than in July. The Moon circles Earth at its actual phase. Hovering the orbit gives the date at that point. The zodiac ring sits outside the orbit, each glyph on the far side of the Sun from Earth, which is the direction the Sun lies in at that time of year; a gold ray marks the current sign.
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CAL
The Calendar
Five columns, one per weekday. Quad and Quin — the rest days — are the shaded columns, and today is the one day drawn in the season's color. Indigo bars are festival days outside the week: New Year's Day above Month 1, the season festivals and Leap Day below their month. Two sky layers are annotated onto the grid without changing it, as small silver marks in the top-right corner of a day: a diamond for the day a solstice or equinox falls in your time zone, a disc for a full moon and a ring for a new moon. The list under the grid names each one with its day. Arrow keys walk the grid; Page Up / Page Down change month.
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5d
The Metric Week
Every month is exactly six 5-day weeks (30 days); festival days sit outside the weeks (see Year Mechanics). The weekdays are named from Latin number words:
Prim (1st), Seco (2nd), Tert (3rd), Quad (4th), Quin (5th). Four is the odd one out: the Latin ordinal is quartus, so strictly it would be "Quart" — Quad comes from the cardinal root instead, and is kept because it is easier to say and to tell apart from Quin.
Three days on, two off. Over a common year that is 216 work days, 144 rest days and 5 festival days — 149 days off out of 365, or 40.8% (a leap year adds a sixth festival: 150 of 366, or 41.0%), where a 7-day week with a 2-day weekend gives 104, or 28.5%. The same ratio arrives in shorter stretches: the longest run of work days is three.
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LEG
The Legacy Column
The old calendar is shown alongside throughout, never instead: the Gregorian month name beside the number, the ordinary clock under the metric digits, today's date beside today's, and a Legacy column in both unit tables. Reading one against the other is the whole point. The Hemisphere control matters for a different reason: which season a quarter of the orbit brings you, and which solstice has your longest day, both depend on where you are standing.
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SIM
Simulator Mode
Flip the LIVE / SIM toggle in the header to freeze the clock and scrub through any moment in the metric year. Two scrubbers appear: Time of Day (under the clock) and Day of Year (under the orbit). You can also click any day on the calendar to jump to it.
04. Year Mechanics
How the year counts up, and how 365.24 real days fit into a 360-day grid.
Human Era (HE) Year Count
- Epoch: 10,000 BCE (approximate start of the Neolithic Revolution — when humans began farming and settled civilization took root).
- Conversion: HE = CE + 10,000. So 2026 CE = 12026 HE.
- Why: Eliminates negative years for prehistoric dates. The pyramids were built around 2500 BCE = 7500 HE — same axis as today, no sign-flips.
- Source: proposed by the geologist Cesare Emiliani in Nature 366, 716 (1993).
Festival Days
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The gap:
12 months × 30 days = 360 — exactly 72 five-day weeks, so every month looks the same and a date always falls on the same weekday. The solar year has 5 days left over (6 in some years). They become festival days outside the week.
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New Year:
New Year's Day opens the year, above Month 1. New Year's Eve closes it, after Month 12 Day 30.
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Quarters:
A festival follows Day 30 of Months 3, 6 and 9 — the 90°, 180° and 270° points of the orbit, where one quarter ends and the next begins. Each is named for the season that quarter brings where you are, so they read in the opposite order south of the equator.
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Leap Day:
Eight years in every 33 run 366 days, with Leap Day just before New Year's Eve. The long years fall at offsets 2, 6, 11, 15, 19, 23, 27 and 31 of the cycle, fitted against the computed equinox dates rather than inherited. The 33-year length is the Persian solar calendar's; the placements within it are not, and the modern Iranian calendar does not use an arithmetic rule at all (see Prior Art).
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Accuracy:
8 leap years in 33 gives a mean year of 365.242424 days against a mean vernal-equinox year of about 365.242374 — roughly one day of drift in 20,000 years, where the Gregorian rule takes about 8,000 to drift the same day.
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Arithmetic:
The rule is arithmetic rather than observational on purpose. A calendar that started each year on whichever date the equinox happened to land would sometimes have no answer at all. In 2172 the equinox misses a UTC midnight by about 90 seconds, and which side of it the year starts on depends on how fast the Earth will be spinning — which nobody can predict decades ahead. An arithmetic rule can be computed for any year, by anyone, forever.
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The sky:
Real seasons aren't equal — Earth moves fastest in January, so northern winter lasts about 89 days and summer about 94 — and equal months can't keep a festival on the exact solstice or equinox (they fall 1–5 days before). The calendar doesn't pretend otherwise: each solstice, equinox, new moon and full moon is computed from the real positions and marked on the day it falls in your time zone, while the grid stays put.
05. Unit Conversion
| Metric Unit |
Value |
Legacy Equiv. |
| 1 Day | 10 Hours | 24 Hours |
| 1 Hour (Deciday) | 100 Minutes | 2.4 Hours (144 min) |
| 1 Centiday | 10 Minutes | 14.4 Minutes |
| 1 Minute (Milliday) | 100 Seconds | 1.44 Minutes (86.4s) |
| 1 Second | Base Unit | 0.864 Seconds |
06. Cosmic Alignment
The year is anchored to the March equinox — the moment the Sun crosses the celestial equator heading north, and the zero point of the sky's coordinate system.
0°
The Anchor
The year opens at 0° of ecliptic longitude. New Year's Day is the day that boundary falls on — it sits outside the week, above the grid — and Month 1 Day 1 is the day after it. Both right ascension and ecliptic longitude are already measured from that point, so anchoring the year there costs nothing and adopts no culture's new year. The HE year number turns over on New Year's Day, which is that boundary; January 1 falls about ten days after the December solstice and marks nothing.
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Months and Degrees
Month n is labeled with the arc it spans, 30(n−1)° to 30n° — so Month 1 runs 0°–30°. The two scales track each other to within about five days and never exactly, because the Sun does not move at a constant rate: Earth is closest in January and fastest there, so equal 30° sectors take between 29.4 and 31.5 days to cross. The degree range says where the month sits, not where the Sun precisely is. The solstices and equinoxes themselves are computed from the Sun's actual position and marked on the days they really fall (see Year Mechanics).
♈
The Signs Are the Sectors
Each month carries a zodiac sign, and the fit is exact rather than lucky: the tropical zodiac is defined as twelve 30° sectors measured from the vernal point, which is the same grid the months are cut from. Month 1 is Aries because both start at 0°. The constellations that lend the signs their names are a different matter — precession has carried them about 24° away from the sectors since the signs were fixed, so the Sun is not in the constellation its sign names. The signs here mean the arcs, not the stars.
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The Moon, Alongside
A lunation runs between 29.27 and 29.83 days, averaging 29.53, and twelve of them fall about eleven days short of a solar year. Calendars that try to satisfy both end up inserting a leap month every few years. Here the Moon is annotated and never given a vote: new and full moons are marked on the days they fall, the panel gives the phase and the lunation number, and the grid does not move for either. Lunations are counted from this calendar's own epoch — the first new moon after the 2000 March equinox it reckons from — rather than from Brown's count, which starts at an arbitrary new moon in 1923.
07. Philosophy
The day and the year are different problems. One is a rotation you may cut wherever you like; the other is an orbit with four points already marked on it. They get different answers here.
The Day: Decimal
Nothing in the sky divides a day, so the only question is which divisions are easy to hold. Ten, then a hundred, then a hundred: every reading is already a percentage of the day, and arithmetic on it is arithmetic on a decimal.
The Year: Twelve Months
The orbit does mark itself: two equinoxes and two solstices, four points 90° apart. A month count worth having divides by 4, so each quarter holds a whole number of them. Of the counts that do — 4, 8, 12, 16 — twelve gives months of about 30 days, nearest a lunation's 29.5, which is where the idea of a month came from. The 12 zodiac sectors are that same 30° grid under older names.
The calendar is a 12 × 30 grid, not a base. Nothing on this page is counted in base 12; the months are simply twelve.
08. Prior Art
Almost every piece of this has been proposed before, usually by someone with better reasons. What is assembled here is the combination.
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Decimal time
Decreed in revolutionary France in October 1793 and made compulsory the following month: ten hours of a hundred minutes of a hundred seconds, exactly the division used here. It was suspended in April 1795, after about seventeen months.
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Days outside the week
The French Republican calendar ran twelve 30-day months and put the five or six remainder days outside the week entirely, as the sansculottides. The festival days here are the same device, which is what keeps every date on the same weekday every year.
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33-year cycle
A 33-year cycle is the classic arithmetic approximation to the solar year, associated with the Persian calendar reform of 1079 under Omar Khayyam's commission. Only the cycle length is borrowed here: the eight leap positions were fitted against computed equinoxes and differ from the traditional Persian placements. The modern Iranian calendar does not use the arithmetic cycle at all — it starts each year on the observed equinox at Tehran.
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Human Era
Cesare Emiliani, "Calendar reform", Nature 366, 716 (1993).
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Astronomy
Jean Meeus, Astronomical Algorithms, 2nd ed. — chapter 27 for the solstices and equinoxes, chapter 49 for the Moon's phases. Both are implemented here from the book; the solstice times agree with USNO to about a minute, the lunar phases to a few.
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Icons
Ten glyphs from Font Awesome Free 6.4.0, © Fonticons, Inc., licensed CC BY 4.0 (opens in a new tab) and inlined in this page.