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Input

Type	Class (static members)
Namespace	`UnityEngine`
System	Old Input Manager
Newer alternative	Input System

Input

The Input class reads the keyboard, mouse and simple gamepad input using the old Input Manager. It's simple and used in most tutorials. For new projects, also look at the Input System.

Requires the old system to be enabledIf Project Settings > Player > Active Input Handling is set to "Input System Package (New)", every call on this page throws an InvalidOperationException. Set it to "Both" to use this class. See Handling Input.

Down, held, up

Most methods come in three flavors:

Suffix	True when	Use for
`...Down`	Only on the one frame the key was pressed	Jump, shoot once, open menu
(none)	Every frame while held	Sprint, automatic fire, charging
`...Up`	Only on the frame it was released	Release a charged attack

Static Methods

Method	Returns	Description
`GetKey(KeyCode key)`	`bool`	Is the key held? e.g. `KeyCode.W`, `KeyCode.LeftShift`.
`GetKeyDown(KeyCode key)`	`bool`	Pressed this frame.
`GetKeyUp(KeyCode key)`	`bool`	Released this frame.
`GetAxis(string axisName)`	`float`	-1 to 1, smoothed. "Horizontal", "Vertical", "Mouse X", "Mouse Y".
`GetAxisRaw(string axisName)`	`float`	Same but not smoothed: -1, 0 or 1 for keys. Snappier.
`GetButton(string buttonName)`	`bool`	Named buttons like "Jump" and "Fire1" (configurable). Also `GetButtonDown`/`Up`.
`GetMouseButton(int button)`	`bool`	0 = left, 1 = right, 2 = middle. Also `Down`/`Up` versions.

Static Properties

Name	Type	Description
`mousePosition`	`Vector3`	Mouse position in pixels. (0,0) is the bottom-left of the screen.
`mouseScrollDelta`	`Vector2`	Scroll wheel movement this frame (use `.y`).
`anyKeyDown`	`bool`	Any key or mouse button pressed this frame. "Press any key to start".
`touchCount`	`int`	Number of fingers on a touchscreen. Use `GetTouch(i)` for details.

Code Samples

Top-down movement

using UnityEngine;

public class TopDownMove : MonoBehaviour
{
    [SerializeField] private float speed = 5f;

    void Update()
    {
        float x = Input.GetAxisRaw("Horizontal");
        float z = Input.GetAxisRaw("Vertical");
        Vector3 dir = new Vector3(x, 0f, z).normalized; // normalized: diagonals aren't faster
        transform.position += dir * speed * Time.deltaTime;
    }
}

Charge-and-release attack

private float chargeStart;

void Update()
{
    if (Input.GetMouseButtonDown(0)) chargeStart = Time.time;

    if (Input.GetMouseButtonUp(0))
    {
        float charge = Mathf.Clamp01((Time.time - chargeStart) / 2f); // full after 2 s
        Debug.Log("Released with " + (charge * 100f) + "% power");
    }
}

What happens at runtime

At the start of each frame, Unity reads the OS input events and updates key states.
GetKeyDown is true for that single frame only. If you check it in FixedUpdate and no physics step runs that frame, you never see it.
GetAxis doesn't jump straight to 1. It moves toward it at the "Sensitivity" speed set in Project Settings > Input Manager, and back toward 0 at the "Gravity" speed.

Common Mistakes

Checking ...Down in FixedUpdate. Presses get missed. Check in Update.
Typos in axis names. GetAxis("horizontal") (lowercase) throws "Input Axis horizontal is not setup". Names are case-sensitive.
Hard-coding keys everywhere. Fine for learning; for real games, the Input System makes rebinding and gamepad support much easier.

Input

Down, held, up

Static Methods

Static Properties

Code Samples

Top-down movement

Charge-and-release attack

What happens at runtime

Common Mistakes

See also