Why did Germany finally decide to surrender in world war 1?

Answer 1

The collapse of German Home Front, caused by awful food shortages, moral and physical tiredness of war and the rise of revolutionary movements, which led to the abdication of Wilhelm II, the armistice and the formation of a Social Democratic government headed by Friedrich Ebert, who then signed the capitulation.
Erich Ludendorff was "quartermaster general" of the army for the last two years of the war, but in actuality he was the real power in Germany, approaching dictatorial power in some cases. With elderly Paul Von Hindenburg, Ludendorff ran Germany's military operations. After Russia quit the war in 1917 the Germans were able to move massive numbers of troops from the east to the western front. Ludendorff knew the war had to be won in 1918 for Germany, or it could not be done, as the American forces were arriving in France and would soon make their weight felt on the battlefield. Ludendorff launched his win-the-war offensive in March 1918. Over the next few months, in all, he launched five major attacks, here and there along the lines. None of these attacks achieved a strategic breakthrough, and by August Germany had exhausted the strength necessary to make such major offensives.

Ludendorff seems to have lost his nerve. He realized that ultimate German defeat was probably only a matter of time, and that Germany could maybe get better terms while its Army was still a powerful force in being, though not strong enough to try to steamroller over the Allies any longer. The Germans were still in possession of most of Belgium and northern France as big bargaining chips.

Ludendorff stunned the civilians of the German government in Berlin when he informed them in August, 1918 that Germany had no choice but to seek an armistice. Having had his own way running the war, he would force the shameful business of making peace onto the civilians.

By the time the Armistice was arranged the Americans were driving north out of the Argonne Forest toward Sedan and Metz. Through those towns ran the single railroad line upon which the German forces in Belgium and France depended for food and supplies. Had the war lasted another week or two the German field armies might have been forced to outright surrender, with no more ammunition with which to continue the fight. Perhaps the greatest mistake of the war was not carrying on until the Germans were utterly defeated, and knew it.

Answer 2

At the end of October 1918, the German fleet at Kiel was ordered to attack the mighty British Navy. The German sailors believed it was a suicidal attack, and instead mutinied. The mutiny spread, and became the German Revolution. Communists tried to take advantage of the chaos to take control of Germany, as Communists had done in Russia the previous year.

With his country turning against him, the Kaiser fled to the Netherlands to stay with his relatives there. The hastily assembled republican government that replaced him then basically surrendered because they had to deal with the revolution, which was getting worse. The revolution ended in 1919 after the failure of the major Communist revolts, and the Weimar Republic was established.