How big was the German Army at the time of its surrender?

Probably around 1.2-1.5 million men; that's total ration strength (Support and rear service troops included), not actual combat strength. There was no chance for the German army to continue fighting; it was hopelessly disorganized, surrounded, outnumbered, outmatched, and basically out of supplies and fuel.
 
the Total number of Wehrmacht personnel in begin of World war 2 was 18 million People (Administration, Support and rear service troops included)
at end of WW2 around 4.3 million were dead or missing in action, 3.4 million s´wounded or sick and around 8.8 million POWs
the number include Waffen-SS forces (foreigner nazis) and Volksstrum (older men and teens from Hitlerjugend)
source: the the military search service "Deutsche Dienststelle (WASt)"

According that source, were only 1.5 million german soldier left (Wehrmacht, SS, Volkssturm and Hitlerjugend)
were other estimation goes to numbers of under 800000 german soldier
I think that is the real number of Soldier.
because the Volkssturm and Hitlerjugend, were untrained old men and boys were Wehrmacht and SS gave them a gun in there hands...

Notes
Volksstrum (eng "storm of the people")
was a German national militia of the last months of World War II, who were only defensive force of their own districts.
mostly males between the ages of 16 to 60 years who were not already serving in Wehrmacht.
form by the Hitler Youth, invalids, the elderly, or men who had previously been considered unfit for military service.
they use not Wehrmacht hardware, but special for this developed cheap, but effective Volkssturm weapons.
The Volkssturm had no effect on the end of world war 2
 
the Total number of Wehrmacht personnel in begin of World war 2 was 18 million People (Administration, Support and rear service troops included)
at end of WW2 around 4.3 million were dead or missing in action, 3.4 million s´wounded or sick and around 8.8 million POWs
the number include Waffen-SS forces (foreigner nazis) and Volksstrum (older men and teens from Hitlerjugend)
source: the the military search service "Deutsche Dienststelle (WASt)"

According that source, were only 1.5 million german soldier left (Wehrmacht, SS, Volkssturm and Hitlerjugend)
were other estimation goes to numbers of under 800000 german soldier
I think that is the real number of Soldier.
because the Volkssturm and Hitlerjugend, were untrained old men and boys were Wehrmacht and SS gave them a gun in there hands...

Notes
Volksstrum (eng "storm of the people")
was a German national militia of the last months of World War II, who were only defensive force of their own districts.
mostly males between the ages of 16 to 60 years who were not already serving in Wehrmacht.
form by the Hitler Youth, invalids, the elderly, or men who had previously been considered unfit for military service.
they use not Wehrmacht hardware, but special for this developed cheap, but effective Volkssturm weapons.
The Volkssturm had no effect on the end of world war 2


During the war itself, the total number of the German Army increased by demographic growth, as the six years of fighting would create another group of people in fighting age, both comming from the Hitler Jugend, as well as from the younger groups, who were addopted in supporting roles at the age of 12 in 1945, meaning they just were about 6 years of age when war started. So the figure of 1.5 million is a bit too low seemingly, as there were still more other sources to get new recruits from, both domestically and from the occupied territories. ("volunteer" groups from all over Europe also joined in with the Wehrmacht during the coinflict.)
 
I tend to think that the number of men had lesser impact on Germanys abilities to fight - they simply had no more resources to continue...

If OTOH the Western Allies had the intention to use a "reformed" Wehrmacht as support for Unthinkable they could have easily released theitr POWs for the job, so the Wehrmacht could actually be much larger ...
 
During the war itself, the total number of the German Army increased by demographic growth, as the six years of fighting would create another group of people in fighting age, both comming from the Hitler Jugend, as well as from the younger groups, who were addopted in supporting roles at the age of 12 in 1945, meaning they just were about 6 years of age when war started. So the figure of 1.5 million is a bit too low seemingly, as there were still more other sources to get new recruits from, both domestically and from the occupied territories. ("volunteer" groups from all over Europe also joined in with the Wehrmacht during the coinflict.)

12 years old in supporting roles !?, i heard story of 13 year old boys as machine-gunners, the last men defending Hitler Bunker was a French from Waffen-SS

I tend to think that the number of men had lesser impact on Germanys abilities to fight - they simply had no more resources to continue...
on resources, they had quite all used up. they try even to build fighter aircraft out of chipboards, most factories were destroyed, bomb back in into stone age...

If OTOH the Western Allies had the intention to use a "reformed" Wehrmacht as support for Unthinkable they could have easily released theitr POWs for the job, so the Wehrmacht could actually be much larger ...

Something similar happen after WW2, the British forces used Wehrmacht units to hunt down gangs, bandits, robbers and plunderer in the British occupied zone.

About the disorganize Wehrmacht,
the german Illustrator Johny Bruck, was on permitted vacation to his family, as he come back to his division he is charge of deserting the Wehrmacht
and almost got executed, only the end of war prevented it.
 
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