The home front during World War I covers the domestic, economic, social and political histories of countries involved in that conflict. For nonmilitary interactions among the major players see diplomatic history of World War I.

About 10.9 million combatants and seven million civilians died during the entire war, including many weakened by years of malnutrition; they fell in the worldwide Spanish flu pandemic, which struck late in 1918, just as the war was ending.

The Allies had much more potential wealth that they could spend on the war. One estimate (using 1913 US dollars), is that the Allies spent $147 billion ($4.5tr in 2023 USD) on the war and the Central Powers only $61 billion ($1.88tr in 2023 USD). Among the Allies, Britain and its Empire spent $47 billion and the United States $27 billion; among the Central Powers, Germany spent $45 billion.H.E. Fisk, The Inter-Allied Debts (1924) pp 13 & 325 reprinted in Horst Menderhausen, The Economics of War (1943 edition), appendix table II

Total war demanded the total mobilization of all the nation's resources for a common goal. Manpower had to be channeled into the front lines (all the powers except the United States and Britain had large trained reserves designed for just that). Behind the lines labor power had to be redirected away from less necessary activities that were luxuries during a total war. In particular, vast munitions industries had to be built up to provide shells, guns, warships, uniforms, airplanes, and a hundred other weapons, both old and new. Agriculture had to be mobilized as well, to provide food for both civilians and for soldiers (many of whom had been farmers and needed to be replaced by old men, boys and women) and for horses to move supplies. Transportation in general was a challenge, especially when Britain and Germany each tried to intercept merchant ships headed for the enemy. Finance was a special challenge. Germany financed the Central Powers. Britain financed the Allies until 1916, when it ran out of money and had to borrow from the United States. The US took over the financing of the Allies in 1917 with loans that it insisted be repaid after the war. The victorious Allies looked to defeated Germany in 1919 to pay "reparations" that would cover some of their costs. Above all, it was essential to conduct the mobilization in such a way that the short term confidence of the people was maintained, the long-term power of the political establishment was upheld, and the long-term economic health of the nation was preserved.Hardach, First World War: 1914–1918 (1981) For more details on economics see Economic history of World War I.

World War I had a profound impact on woman suffrage across the belligerents. Women played a major role on the homefronts and many countries recognized their sacrifices with the vote during or shortly after the war, including the United States, Britain, Canada (except Quebec), Denmark, Austria, the Netherlands, Germany, Russia, Sweden and Ireland. France almost did so but stopped short.

Financial costs

The total direct cost of war, for all participants including those not listed here, was about $80 billion in 1913 US dollars—around $2.47 trillion in 2023 dollars. Direct cost is figured as actual expenditures during war minus normal prewar spending. It excludes postwar costs such as pensions, interest, and veteran hospitals. Loans to/from allies are not included. Repayment of loans after 1918 is not included.Harvey Fisk, The Inter-Ally Debts: An Analysis of War and Post-War Public Finance, 1914-1923 (1924) pp 1, 21-37 The total direct cost of the war as a percent of wartime national income: Allies: Britain, 37%; France, 26%; Italy, 19%; Russia, 24%; United States, 16%. Central Powers: Austria-Hungary, 24%; Germany, 32%; Turkey unknown. The amounts listed below are presented in terms of 1913 US dollars, where $1 billion then equals about $25 billion in 2017.Fisk, The Inter-Ally Debts pp 21-37. Britain had a direct war cost about $21.2 billion; it made loans to Allies and Dominions of $4.886 billion, and received loans from the United States of $2.909 billion. France had a direct war cost about $10.1 billion; it made loans to Allies of $1.104 billion, and received loans from Allies (United States and Britain) of $2.909 billion. Italy had a direct war cost about $4.5 billion; it received loans from Allies (United States and Britain) of $1.278 billion. The United States had a direct war cost about $12.3 billion; it made loans to Allies of $5.041 billion. Russia had a direct war cost about $7.7 billion; it received loans from Allies (United States and Britain) of $2.289 billion.Peter Gatrell, Russia's First World War: A Social and Economic History (2005) pp 132-53

The two governments agreed that financially Britain would support the weaker Allies and that France would take care of itself.Martin Horn, Britain, France, and the financing of the First World War (2002) ch 1. In August 1914, Henry Pomeroy Davison, a Morgan partner, traveled to London and made a deal with the Bank of England to make J.P. Morgan & Co. the sole underwriter of war bonds for Great Britain and France. The Bank of England became a fiscal agent of J.P. Morgan & Co., and vice versa. Over the course of the war, J.P. Morgan loaned about $1.5 billion (approximately $ billion in today's dollars) to the Allies to fight against the Germans. Morgan also invested in the suppliers of war equipment to Britain and France, thus profiting from the financing and purchasing activities of the two European governments.

Britain made heavy loans to Tsarist Russia; the Lenin government after 1920 refused to honor them, causing long-term issues.Jennifer Siegel, For Peace and Money: French and British Finance in the Service of Tsars and Commissars (Oxford UP, 2014).

Britain

At the outbreak of war, patriotic feelings spread throughout the country, and many of the class barriers of Edwardian era faded during the years of combat.National Archives "The war and the changing face of British society" However, overnight, the Catholics in southern Ireland moved to demand for complete immediate independence after the failed Easter Rebellion of 1916. Northern Ireland remained loyal to the crown.

In 1914 Britain had by far the largest and most efficient financial system in the world.Christopher Godden, "The Business of War: Reflections on Recent Contributions to the Economic and Business Histories of the First World War." Œconomia. History, Methodology, Philosophy 6#4 (2016): 549-556. online Roger Lloyd-Jones and M. J. Lewis argue: To prosecute industrial war required the mobilization of economic resources for the mass production of weapons and munitions, which necessarily entitled fundamental changes in the relationship between the state (the procurer), business (the provider), labor (the key productive input), and the military (the consumer). In this context, the industrial battlefields of France and Flanders intertwined with the home front that produced the materials to sustain a war over four long and bloody years.Roger Lloyd-Jones and M. J. Lewis, Arming the Western Front: War, Business and the State in Britain, 1900–1920 (Routledge, 2016), p 1.

Economic sacrifices were made, however, in the name of defeating the enemy.Stephen Broadberry and Peter Howlett, "The United Kingdom during World War I: business as usual?" in Broadberry and Harrison, eds. The Economics of World War I (2005) ch 7 In 1915 Liberal politician David Lloyd George took charge of the newly created Ministry of Munitions. He dramatically increased the output of artillery shells—the main weapon actually used in battle. In 1916 he became secretary for war. Prime Minister H. H. Asquith was a disappointment; he formed a coalition government in 1915 but it was also ineffective. Asquith was replaced by Lloyd George in late 1916. He had a strong hand in the managing of every affair, making many decisions himself. Historians credit Lloyd George with providing the driving energy and organisation that won the War.A.J.P. Taylor, English History, 1914–1945 (1965) pp. 34–5, 54, 58, 73–76

Although Germans were using Zeppelins to bomb the cities, morale remained relatively high due in part to the propaganda churned out by the national newspapers.Ian F. W. Beckett, The Great war (2nd ed. 2007) pp 394–395 With a severe shortage of skilled workers, industry redesigned work so that it could be done by unskilled men and women (termed the "dilution of labour") so that war-related industries grew rapidly. Lloyd George cut a deal with the trades unions—they approved the dilution (since it would be temporary) and threw their organizations into the war effort.Beckett (2007), pp. 341, 455

Historian Arthur Marwick saw a radical transformation of British society, a deluge that swept away many old attitudes and brought in a more equalitarian society. He also saw the famous literary pessimism of the 1920s as misplaced, for there were major positive long-term consequences of the war. He pointed to new job opportunities and self-consciousness among workers that quickly built up the Labour Party, to the coming of partial woman suffrage, and an acceleration of social reform and state control of the British economy. He found a decline of deference toward the aristocracy and established authority in general, and a weakening among youth of traditional restraints on individual moral behavior. Marwick concluded that class differentials softened, national cohesion increased, and British society became more equal.Arthur Marwick, The Deluge: British Society and the First World War (1965) During the conflict, the various elements of the British Left created the War Emergency Workers' National Committee, which played a crucial role in supporting the most vulnerable people on the Home Front during the war, and in ensuring the British Labour remained united in the years after the Armistice.David Swift, "The War Emergency: Workers' National Committee." History Workshop Journal 81 (2016): 84-105.

Scotland