Solar Eclipse Calculator
Solar Eclipse Calculator
Countdown to Next Solar Eclipse
Next Eclipse: February 6, 2027 (Annular)
Upcoming Solar Eclipses
Click any row to view full details
Select an Eclipse for Details
Click any row in the eclipse list to view contact times, magnitude, obscuration, Saros series, and path information for that event.
Eclipse Type Distribution (2025–2030)
Magnitude Scale
Explore upcoming solar eclipses with magnitude, contact times, Saros series, and real-time countdown
Welcome to our free Solar Eclipse Calculator, the most comprehensive client-side eclipse reference tool available. Whether you are a casual skywatcher, an astronomy enthusiast, or a science educator, this tool gives you everything you need to understand and prepare for upcoming solar eclipses — all running entirely in your browser with no account required. A solar eclipse occurs when the Moon passes between the Earth and the Sun, casting a shadow on Earth's surface. The exact nature of the eclipse — whether it appears total, annular, partial, or hybrid — depends on the orbital geometry of the Moon at the precise moment of alignment. Because the Moon's orbit is elliptical, its apparent angular size in the sky varies between about 29.4 and 33.5 arcminutes. Similarly, Earth's distance from the Sun shifts the Sun's apparent angular diameter between about 31.6 and 32.7 arcminutes. When these two values align just right, spectacular celestial events result. This calculator presents a pre-computed database of all solar eclipses from 2025 through 2030, drawn from NASA's Five Millennium Canon of Solar Eclipses and cross-referenced with EclipseWise.com data. Each entry includes the eclipse type, magnitude, obscuration percentage, Saros series number, contact times in UTC, maximum duration of totality or annularity, path width, greatest eclipse coordinates, and the geographic regions where the eclipse is visible. One of the most important but often confused distinctions is between eclipse magnitude and eclipse obscuration. Magnitude measures the fraction of the Sun's linear diameter covered by the Moon — it can exceed 1.0 for total eclipses. Obscuration measures the fraction of the Sun's area covered, expressed as a percentage — and because area scales with the square of diameter, obscuration is always less than or equal to magnitude for partial eclipses. For example, a magnitude of 0.94 corresponds to roughly 89% obscuration. Understanding both values helps you predict how dramatically the sky will darken during the event. Contact times define the four key moments of any solar eclipse. C1 (First Contact) is when the Moon's disk first touches the Sun's disk — the start of the partial phase. C2 (Second Contact) is the instant total or annular eclipse begins for central observers. C3 (Third Contact) marks the end of totality or annularity. C4 (Fourth Contact) is when the Moon completely leaves the Sun, ending the event. For partial eclipses, only C1 and C4 occur. All times in this calculator are given in Coordinated Universal Time (UTC); convert to your local time zone as needed. The Saros cycle is an 18-year, 11-day, 8-hour period after which solar eclipses repeat in the same family with nearly identical geometry. A single Saros series typically spans 1,200 to 1,550 years and contains 69 to 87 eclipses. The extra 8 hours in each Saros period shifts the eclipse path roughly 120 degrees westward — it takes three Saros periods (the Exeligmos, or 54 years 33 days) for an eclipse to return to the same longitude. Understanding Saros series helps astronomers and historians connect modern eclipses to ancient records and predict future events centuries in advance. Upcoming highlights include the total solar eclipse of August 12, 2026 — crossing Greenland, Iceland, Spain, Portugal, and western Russia with up to 2 minutes 18 seconds of totality — and the spectacular total eclipse of August 2, 2027 over North Africa and the Arabian Peninsula, offering 6 minutes 23 seconds of totality, one of the longest of the 21st century. Use the countdown timer and eclipse list in this tool to plan your observation well in advance.
Understanding Solar Eclipses
Solar eclipses are among the most awe-inspiring astronomical events, arising from a precise geometric alignment of the Sun, Moon, and Earth. Understanding the key concepts helps you interpret eclipse data correctly.
Eclipse Types: Total, Annular, Partial, and Hybrid
The four types of solar eclipses are determined by the Moon's apparent angular size compared to the Sun's. A total eclipse occurs when the Moon is close enough to Earth (near perigee) that its disk completely covers the Sun — observers in the umbral shadow witness day turning to night, the solar corona becomes visible, and stars appear. An annular eclipse occurs when the Moon is near apogee and appears slightly smaller than the Sun, leaving a 'ring of fire' annulus around the Moon's silhouette. A partial eclipse means only the penumbral shadow sweeps Earth's surface — the Moon covers part but not all of the Sun's disk. A hybrid eclipse is the rarest type, transitioning between total and annular along the central path as Earth's curvature causes different parts of the path to fall in the umbra versus antumbra.
Magnitude vs. Obscuration
These two values are frequently confused but measure different things. Eclipse magnitude is the fraction of the Sun's diameter (a linear measure) covered by the Moon. A magnitude of 1.0 means the Moon's diameter exactly equals the Sun's apparent diameter — the defining boundary between total and annular eclipses. Magnitudes above 1.0 indicate total eclipses; below 1.0 indicate partial or annular. Eclipse obscuration measures the fraction of the Sun's area covered by the Moon, expressed as a percentage. Because area scales as the square of linear dimension, obscuration is always lower than magnitude for partial eclipses. For a magnitude of 0.50, only about 39% of the Sun's area is covered. For a magnitude of 0.94, about 89% of the Sun's area is obscured — which explains why even large partial eclipses don't dramatically darken the sky until magnitude exceeds roughly 0.98.
The Saros Cycle and Eclipse Families
The Saros cycle is 6,585.3211 days — exactly 223 synodic months, which also equals 239 anomalistic months and 242 draconic months. This triple coincidence means that after one Saros period, the Sun, Moon, and Moon's node return to nearly the same relative positions, producing a very similar eclipse. Eclipses within the same Saros series share a family number (e.g., Saros 136, which includes the famous 7-minute 28-second total eclipse of 1973). Each successive eclipse in a series shifts about 120 degrees westward in longitude (because of the extra 8 hours). After three Saros periods — the Exeligmos of 54 years 33 days — the eclipse returns to nearly the same longitude. NASA has cataloged Saros series 0 through 180 for solar eclipses.
Eclipse Safety and Viewing
Viewing the Sun without proper eye protection is extremely dangerous and can cause permanent retinal damage within seconds. The only safe time to look directly at the Sun during an eclipse with the naked eye is during the brief totality phase of a total eclipse — and only if you are within the path of the umbra. Before and after totality (and during annular and partial eclipses for their entire duration), use certified solar eclipse glasses that meet the ISO 12312-2 international standard. Ordinary sunglasses, even very dark ones, are completely insufficient. Alternatives include solar projection using a pinhole camera or through a colander, and solar filters specifically designed for telescopes and binoculars. Never look through an unfiltered telescope at the Sun. Plan your viewing location in advance, confirm your safety equipment, and check weather forecasts — eclipse paths are often narrow and cloud cover can spoil the experience.
Formulas
The period after which nearly identical eclipses repeat. It equals 223 synodic months, 239 anomalistic months, and 242 draconic months simultaneously, ensuring the Sun, Moon, and lunar nodes return to nearly the same relative positions.
The fraction of the Sun's linear diameter covered by the Moon at maximum eclipse. A magnitude of 1.0 means the Moon exactly covers the Sun. Values above 1.0 indicate total eclipses where the Moon appears larger than the Sun.
Converts linear magnitude (m) to area obscuration. Because area scales with the square of diameter, a magnitude of 0.50 produces only about 39% obscuration, while a magnitude of 0.94 yields roughly 89% obscuration.
The apparent angular size of the Moon varies from 29.4 arcminutes (at apogee, d = 405,500 km) to 33.5 arcminutes (at perigee, d = 356,500 km). This variation determines whether an eclipse is total or annular.
Reference Tables
Solar Eclipse Types
| Type | Frequency | Moon Distance | Max Duration | Key Feature |
|---|---|---|---|---|
| Total | ~27% of central eclipses | Near perigee | Up to 7 min 32 sec | Corona visible, sky goes dark |
| Annular | ~33% of central eclipses | Near apogee | Up to 12 min 30 sec | 'Ring of fire' annulus visible |
| Partial | ~35% of all eclipses | Varies | N/A (no totality) | Only penumbral shadow on Earth |
| Hybrid | ~5% of central eclipses | Near boundary | Varies | Switches total/annular along path |
Upcoming Solar Eclipses (2025-2028)
| Date | Type | Magnitude | Max Duration | Visible Regions |
|---|---|---|---|---|
| Mar 29, 2025 | Partial | 0.938 | N/A | NW Africa, Europe, N Russia |
| Sep 21, 2025 | Partial | 0.855 | N/A | S Pacific, New Zealand, Antarctica |
| Aug 12, 2026 | Total | 1.039 | 2m 18s | Greenland, Iceland, Spain |
| Feb 6, 2027 | Annular | 0.928 | 7m 51s | S Pacific, Argentina, Atlantic |
| Aug 2, 2027 | Total | 1.079 | 6m 23s | Morocco, Spain, Algeria, Egypt |
| Jan 26, 2028 | Annular | 0.921 | 10m 27s | Ecuador, Peru, Brazil, Spain |
| Jul 22, 2028 | Total | 1.056 | 5m 10s | Australia, New Zealand |
Worked Examples
Calculating Obscuration from Magnitude
Use the obscuration formula with m = 0.75
Calculate arccos(1 - 2(0.75)) = arccos(-0.5) = 2.094 radians
Calculate (1 - 2(0.75)) x sqrt(4(0.75) - 4(0.75)^2) = -0.5 x sqrt(0.75) = -0.433
Obscuration = (2.094 - (-0.433)) / pi = 2.527 / 3.14159 = 0.804
Multiply by 100 to get percentage: 80.4%
Finding the Next Eclipse in a Saros Series
Add one Saros period: 6585.3211 days = 18 years, 11 days, 8 hours
2017 + 18 years = 2035
August 21 + 11 days = September 1
The extra 8 hours shifts the path ~120 degrees westward
Determining Eclipse Type from Angular Sizes
Calculate Moon's angular diameter: 2 x arctan(1737.4 / 370000) = 0.00939 radians = 32.3 arcminutes
Compare Moon's angular diameter (32.3') to Sun's angular diameter (31.9')
Moon appears larger than the Sun: 32.3' > 31.9'
Eclipse magnitude = 32.3 / 31.9 = 1.013 (exceeds 1.0)
How to Use the Solar Eclipse Calculator
Check the Countdown and Next Eclipse
The top of the results panel shows a live countdown to the next upcoming solar eclipse. This updates in real time so you always know how many days, hours, minutes, and seconds remain until the next eclipse event occurs anywhere on Earth.
Browse or Filter the Eclipse List
Use the Eclipse Type filter to narrow the list to Total, Annular, Partial, or Hybrid eclipses. The table shows date, type, magnitude, Saros series number, maximum duration, and visible regions for each upcoming eclipse from 2025 through 2030.
Select an Eclipse for Full Details
Click any row in the eclipse table to load the full detail panel on the right. You will see contact times C1 through C4 in UTC, eclipse magnitude and obscuration with a visual ring diagram, greatest eclipse coordinates, path width, and population statistics.
Export or Print Your Eclipse Report
Use the Export CSV button to download the full eclipse list as a spreadsheet for offline reference or trip planning. Use the Print button to generate a clean, print-friendly eclipse report with all details for the selected event.
Frequently Asked Questions
What is the difference between a total and an annular solar eclipse?
A total solar eclipse occurs when the Moon's apparent angular diameter is larger than the Sun's — meaning the Moon is close enough to Earth (near perigee) to completely cover the Sun's disk. Observers in the central path (the umbral shadow) experience a few minutes of darkness, can see the solar corona with the naked eye, and see stars appear. An annular solar eclipse occurs when the Moon is near apogee and appears slightly smaller than the Sun. Even though the Moon is centered on the Sun, a bright ring (annulus) of sunlight remains visible around the Moon's silhouette. Annular eclipses cannot produce coronal views. Hybrid eclipses switch between total and annular along the eclipse path as Earth's curvature changes the relative distances.
What do the contact times C1, C2, C3, and C4 mean?
The four contact times define the key phases of a solar eclipse. C1 (First Contact) is when the Moon's limb first touches the Sun's limb — this marks the beginning of the partial eclipse phase. C2 (Second Contact) is when the Moon fully enters the Sun's disk, marking the start of totality or annularity for observers on the central line. C3 (Third Contact) is when the Moon's limb again touches the Sun's limb as it begins to exit — this marks the end of totality or annularity. C4 (Fourth Contact) is when the Moon completely leaves the Sun's disk, ending the partial phase and the entire eclipse. For observers seeing only a partial eclipse, C2 and C3 do not occur. All contact times in this calculator are given in Coordinated Universal Time (UTC).
Why is the eclipse magnitude sometimes greater than 1.0?
Eclipse magnitude measures the fraction of the Sun's linear diameter covered by the Moon. For a total eclipse, the Moon's apparent diameter is larger than the Sun's, so magnitude exceeds 1.0. For example, the August 12, 2026 total eclipse has a magnitude of approximately 1.05, meaning the Moon appears about 5% larger in diameter than the Sun at that moment. A magnitude of exactly 1.0 would mean the Moon's edge precisely matches the Sun's — the theoretical boundary between total and annular eclipses. Magnitudes above 1.0 always indicate total eclipses. Magnitudes between 0 and 1.0 indicate partial or annular eclipses, depending on whether the Moon is fully within the Sun's disk.
What is a Saros series, and why does it matter?
A Saros series is a family of solar eclipses that repeat with similar geometry every 6,585.3 days (18 years, 11 days, and about 8 hours). This period is special because 223 synodic months (Moon's cycle relative to the Sun), 239 anomalistic months (Moon's elliptical orbit cycle), and 242 draconic months (Moon's node crossing cycle) all coincide almost exactly. After one Saros period, the Sun, Moon, and lunar node return to nearly identical relative positions, producing a nearly identical eclipse — but shifted about 120 degrees westward in longitude due to the extra 8 hours. The Saros number is essentially the eclipse's family name. Saros 136, for example, includes some of the longest total solar eclipses in history.
How can I find out if a solar eclipse is visible from my location?
Each eclipse entry in this calculator lists the visible regions where the eclipse can be observed — these are broad geographic areas where some portion of the eclipse is visible. For a total or annular eclipse, the central path (umbral or antumbral shadow) is narrow, often only 50 to 300 kilometers wide, and moves rapidly across Earth's surface. Only observers within this narrow band see totality or annularity. Observers within a few thousand kilometers on either side of the central path see a partial eclipse of varying magnitude. The greatest eclipse coordinates (latitude and longitude) show where the eclipse reaches its maximum magnitude. For precise local contact times and local magnitude, specialized per-city calculators using Besselian elements and your exact coordinates are needed.
Is it safe to photograph a solar eclipse without a filter?
Photographing the Sun without a proper solar filter on your camera or telescope lens can permanently damage your camera sensor and — if you look through an optical viewfinder — your eyes. During the partial phases before and after totality, and during any annular or partial eclipse, a certified solar filter must be placed in front of the camera lens or telescope objective. Only during the brief totality phase of a total solar eclipse can you remove the filter to capture the corona, prominences, and chromosphere. Use an intervalometer or remote shutter release to minimize vibration. For video, shoot in high frame rate to capture the diamond ring and Baily's beads at second and third contact. Always reattach the solar filter before totality ends.