United Kingdom is approximately 243,610 sq km, while New Caledonia is approximately 18,575 sq km, making New Caledonia 7.62% the size of United Kingdom. Meanwhile, the population of United Kingdom is ~65.8 million people (65.5 million fewer people live in New Caledonia).
This to-scale map shows a size comparison of United Kingdom compared to New Caledonia. For more details, see an in-depth quality of life comparison of New Caledonia vs. United Kingdom using our country comparison tool.