Amazon River
The Amazon River is a major waterway in South America that flows eastward across the continent and drains a vast rainforest basin.
Also known as: Amazon, Rio Amazonas
How big is it?
6,400 km · approximate main-channel length
Also 3,977 mi
Approximate main-channel length · approximate
Typical recorded range: 6,200 km to 6,800 km.
A little perspective
Amazon River vs Mars: length comparison
The mean diameter of Mars is about 1.06 times the main-channel length of the Amazon River.
The Amazon River is a major waterway in South America that flows eastward across the continent and drains a vast rainforest basin.
Mars is a rocky planet orbiting the Sun, with a reddish surface due to iron oxide.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
Measurements, assumptions & sources +
Amazon River
Approximate main-channel length: 6,400 km; approximate; range 6,200 km–6,800 km.
The Amazon is represented by a rounded 6,400 km main-channel length. Its source and channel conventions are disputed, so published totals differ; the line is not a route map.
Encyclopaedia Britannica — Amazon River and rainforest
The marked approximate main-channel length is calibrated. Unmeasured illustration details are representative.
Mars
Mean diameter: 6,779 km; approximate.
Mean-radius spherical model for Mars; actual shape is not perfectly spherical.
NASA JPL — planetary physical parameters
The marked mean diameter is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Why this measurement?
Why we use 6,400 km
We compare the main-channel length of the Amazon River. This is an estimate; check the notes for its rounding and uncertainty. The recorded range is 6,200 km to 6,800 km.
The Amazon is represented by a rounded 6,400 km main-channel length. Its source and channel conventions are disputed, so published totals differ; the line is not a route map.
The marked horizontal span follows the measured feature, not the edges of the image. How calibrated comparisons work →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 6,400 km | 6,200 km to 6,800 km | approximate |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valuePlaces and natural featuresYenisei5,539 kmApproximate river-system lengthThe Yenisei is a major river in Siberia, Russia, flowing northwards from Mongolia to the Arctic Ocean.
Around the same scalePlanets, moons and spaceMars6,779 kmMean diameterMars is a rocky planet orbiting the Sun, with a reddish surface due to iron oxide.Nearest higher valuePlaces and natural featuresNile6,650 kmApproximate river-system lengthThe Nile is a prominent river in northeastern Africa, flowing northward through several countries before reaching the Mediterranean Sea.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- Encyclopaedia Britannica — Amazon River and rainforestRounded river length and broad rainforest-area context; geographic definitions vary.
There’s always another scale
Follow your curiosity.
PlacesAmazon rainforest5,500,000 km²The Amazon rainforest is a dense tropical forest in South America, home to a rich diversity of plant and animal life.PlacesNile6,650 kmThe Nile is a prominent river in northeastern Africa, flowing northward through several countries before reaching the Mediterranean Sea.SpaceMars6,779 kmMars is a rocky planet orbiting the Sun, with a reddish surface due to iron oxide.
SpaceGanymede5,262 kmGanymede is a natural satellite of Jupiter and contains a magnetic field generated by its partially liquid core.
SpaceTitan5,150 kmTitan is a natural satellite of Saturn, with a thick nitrogen-rich atmosphere and surface lakes of hydrocarbons.
SpaceMercury4,879 kmMercury is a rocky planet orbiting closest to the Sun in the Solar System.
SpaceCallisto4,821 kmCallisto is a natural satellite of Jupiter, with a heavily cratered icy surface.
SpaceIo3,643 kmIo is a natural satellite of Jupiter, covered with active volcanoes and sulphur deposits.