Every major navy entered the war with a different readiness gap

Which navy was closest to being ready for the Second World War?

None was fully ready: each had a different combination of missing ships, aircraft, bases, logistics, or supporting infrastructure.

A single ranking of wartime preparedness fails because readiness had several dimensions. Britain possessed worldwide infrastructure but lacked the desired fleet and naval aircraft, while Germany was broadly unready. Italy had many of its intended ships without the infrastructure to support them, and Japan was short in both categories. The United States was comparatively strong in infrastructure but still lacked the wartime fleet it wanted. Bases, repair, supply, and industrial support mattered as much as counting ships.