Several well-known flags are white with a red cross, so the answer depends on the exact design you’re thinking of.

Most likely answers

1. Flag of England (St George’s Cross)

  • Design: A simple red upright cross that reaches the edges of a white field.
  • Meaning: The cross of Saint George, associated with medieval crusaders and later adopted as the flag of England and of the city-state of Genoa.
  • Usage today:
    • National flag of England (within the UK).
    • Very common at football (soccer) matches and other sporting events.

If your question is “what flag is white with a red cross” and the cross fills the whole flag, this is usually the one people mean.

2. Red Cross emblem (humanitarian symbol)

  • Design: A red cross with equal arms on a white background, usually centered, not always stretching to the edges like a national flag.
  • Meaning: Protection symbol under the Geneva Conventions, identifying medical and humanitarian services of the International Red Cross and Red Crescent Movement.
  • Important detail: It is not meant as a religious symbol; it is the color inversion of the Swiss flag and is legally protected in many countries.

You’ll see this on ambulances, field hospitals, and humanitarian workers’ uniforms rather than on a typical national flagpole.

Other similar white‑and‑red cross flags

There are also other designs that people sometimes confuse:

  • Christian flag: White field with a blue canton (top-left) containing a small red Latin cross.
  • Various regional or historical flags: Some local, military, or historical banners use a red cross on white with extra symbols, stripes, or coats of arms.

How to tell which one you’re seeing

Ask yourself:

  1. Does the cross reach the edges of the flag?
    • Yes, upright cross to the edges → most likely the flag of England (St George’s Cross).
  1. Is it on a hospital, ambulance, or aid worker’s vest and not flying like a national flag?
    • Yes → almost certainly the Red Cross emblem (humanitarian symbol).
  1. Is there a blue box in the corner with a small red cross inside it?
    • Yes → the Christian flag.

If you describe the exact layout (does it touch the edges, is there blue anywhere, where is the cross placed?), I can narrow it down to one specific flag.

Information gathered from public forums or data available on the internet and portrayed here.