Published Amazon River length estimates differ. NASA reports one estimate of 6,800 kilometers; a peer-reviewed satellite-imagery and field study calculated 6,575 kilometers (4,086 miles). The difference reflects choices about the river's farthest source, mouth, and measurement method, so there is no single universally agreed length.
A quick visual reference is roughly 4,000–4,250 miles depending on which published estimate is used.
| Published reference | Kilometers | Miles | How to read it |
|---|---|---|---|
| Liu et al. (2009) | 6,575 km | 4,086 mi | Calculated using satellite imagery and field investigation of source regions |
| NASA-reported estimate | 6,800 km | About 4,225 mi | NASA reports 6,800 km; miles here are converted from kilometers |
River length depends on which tributary headwater is treated as the source, where the mouth is placed, map scale, and measurement method. The peer-reviewed study notes earlier published Amazon values ranged widely; report the source and method when quoting one exact figure.
The Amazon Waters Alliance describes the main river channel's average depth as varying roughly from 15 to 40 meters (about 49 to 131 feet) and its average width as about 2 to 3 kilometers (roughly 1.2 to 1.9 miles). These are channel references, not fixed dimensions along the whole river.
Depth changes by reach and water level. In a 2025 study, measurements at Careiro varied from about 21 to 25 meters between low- and high-flow conditions. That is a location-specific example, not a riverwide average.
The Amazon River is the channel; the Amazon Basin is the land area drained by the river and its tributaries. The Science Panel for the Amazon describes the basin as about 7 million square kilometers (around 2.7 million square miles), spanning nearly 40% of South America.
That basin-area figure is not the river's width or length. The basin includes multiple connected rivers, wetlands, floodplains, and upland areas.
These facts describe different parts of the Amazon system; basin size, channel depth, and total river length are separate measurements.
One peer-reviewed estimate is 4,086 miles (6,575 km). NASA reports another estimate of 6,800 km, about 4,225 miles after conversion.
There is no one depth for the entire river. Amazon Waters gives a channel-average range of about 15–40 meters; depth depends on the reach and flow conditions.
Amazon Waters reports an average channel width around 2–3 km in the described main-channel context. Islands, multiple channels, floodplains, and seasonal water levels make width vary by location.
The answer depends on the chosen Amazon and Nile headwaters, endpoints, and measurement method. The length study cited here calculated the Amazon at 6,575 km and the Nile at 7,088 km using its method; other estimates differ.
The Science Panel for the Amazon describes the watershed as about 7 million km². That is drainage-basin area, not the surface area of the river channel.
Kilometer-to-mile values not supplied directly by a source are rounded conversions. Length values are attributed to their source because river endpoints, headwaters, and measurement techniques affect the result.