The allies outcome of D-Day was successful even though there was much blood shed , around 1,000 American soldiers died at Omaha a sector of the the American force. A reason the allies won by a so much is because of the planning. Another reason they won is Germany thought the attack was going to be at another location. The person leading the operation overlord was Dwight D. Eisenhower he picked the size of the troops the date etc. the number of infantry that came into Europe the month of June was over 800,000 . So the effect of D-Day was excremental during the war.