The size of the forces were greatly unequal: around 10,000–15,000 on the English side and 20,000–25,000 on the French side. But Englishmen took all the advantages they could: As in previous battles against the Scots, Edward III disposed his forces in an area of flat agricultural land, choosing high ground surrounded by natural obstacles on the flanks. The king installed himself and his staff in a windmill on a small hill that protected the rear, where he could direct the course of the battle. His army had carried with them much food and wine from their prior victories and were allowed to prepare their weaponry and to rest before the battle. The French had no time to rest, a disadvantage in that the men were tired and the crossbowmen's equipment was still wet.

In this battle crossbowmen proved completely useless; with a shooting rate of around 1–2 shots per minute, they were no match for the longbowmen, who could shoot five or six arrows in the same amount of time, and also had superior range due to their bows and elevation. Under the hail of English arrows, the crossbowmen suffered heavy losses and were unable to approach the English lines to where their crossbows would have been effective. Frustrated and confused, the crossbowmen retreated. The knights and nobles, upon seeing the mercenaries routed, hacked them down as they came back to their lines.

Ribaldis, a type of cannon, were first mentioned during preparations for the battle between 1345 and 1346. Contemporary chronicler wrote that they were destructive on the field: "The English guns cast iron balls by means of fire...They made a noise like thunder and caused much loss in men and horses...The Genoese were continually hit by the archers and the gunners... the whole plain was covered by men struck down by arrows and cannon balls".