Reach (Arm Reach / Working Radius)

The farthest distance a fully extended arm can reach from its base center — a basic spec for choosing a robot.

Reach is a basic spec on a robot arm's datasheet, generally meaning the maximum distance from the base's rotation center to the wrist center or the flange (the interface where the end-of-arm tool mounts); the exact measurement point depends on each manufacturer's datasheet. It roughly outlines the outer boundary of the workspace (every position the end effector can reach) — an arm with an 0.85 m reach can cover, very roughly, a region of radius 0.85 m centered on the base. But reach doesn't equal a genuinely usable range: as the arm nears full extension it approaches a singular configuration (a posture where the end effector can't move in certain directions), losing dexterity and constraining end-effector orientation; the gripper's own length and the torque limits imposed by the payload also eat into the practical range. For tabletop or mobile manipulation, reach determines how deep a table can be or how close a mobile base has to park, and it's also commonly used to compare a humanoid's arm against a human arm.

ExampleFranka Research 3's official specs list an 855 mm reach, a 3 kg payload, and 7 degrees of freedom. Mounted at the edge of a table, it likely can't reach an object about 1 meter from that edge — the base would need to move closer, or the object would need to be moved in.

Also called

Arm Reach, Working Radius, Max Reach

Related

Workspace · Robotic Arm · Payload · Singular Configuration (Kinematic Singularity) · Reachability Map / Inverse Reachability Map · Degrees of Freedom (DoF)

Sources

Franka Robotics: Franka Research 3
Modern Robotics (Lynch & Park), Ch.2 Task Space and Workspace

As of

2026-09