Over a decade the modern and pre-1914 build-ups converge even more closely. Germany today is at +118%; Austria-Hungary managed +113% and the Kaiser’s Germany +109% over the ten years to 1913. Russia today is at +96% against Russia’s own +77% before the First World War.

There is no true ten-year window for the 1930s. German rearmament began in 1933 and the war came in 1939, so the entire build-up lasted six years. The panel above uses 1930–38, the longest defensible span, and even then Germany runs thirty times past the edge of the chart.

Britain’s flat line is partly a base effect. The 1903 figure still carried Boer War costs, so the ten-year comparison understates British growth; measured from 1908, British spending rose 31%.

Sources. 1908–13 and 1903–13: Correlates of War, National Material Capabilities v7.0, variable milex (total military expenditure, army and navy combined), thousands of current pounds sterling. 1930–38 and 1933–38: the same dataset, thousands of current US dollars. 2015–25 and 2020–25: SIPRI, constant 2024 US dollars. Percentage changes are calculated from the published values.

The Correlates of War figure for German spending in 1939 is not used here. In the published dataset that value is hand-entered rather than drawn from a statistical yearbook, and every other power’s 1939 entry has no source recorded at all, so the interwar panel stops at 1938.

These series are not perfectly like for like. All three panels now show total military spending, but only the modern column is inflation-adjusted; the two historical columns are in current prices. Currency changes too — the Correlates of War series is denominated in pounds before 1914 and dollars afterwards, so there is no continuous line across the two eras. Read this as scale, not as measurement.