The estimates of the sizes of two armies of knights that clashed in Grunwald vary depending on the source and time. They were often biased by political and nationalistic considerations. None of the contemporary sources provided reliable troop counts. One German source estimated Polish army to have 1.5 million troops.
According to the most acceptable estimate the army of Jagiełło and Witold counted from 20 to 50 thousand people, the regiments of Ulrich von Jungingen – from 18 to 40 thousand people (including 250 Teutonic Knights).
The Battle of Grunwald was one of the biggest in the Latin Europe, and also one of the bloodiest ones: the total losses in men on the Teutonic Order side, including dead, seriously wounded and captured, are estimated to be about 50 to 80 percent (only 43 Teutonic Knights remained alive), on the Lithuanian side the losses were almost 50 percent, while the losses on the Polish side seemed to be very low.
For more information please read this article: "The Battle of Grunwald and Other Great Battles of The Middle Ages" by Sławomir Patlewicz
