Landing craft and ships unload troops and supplies at Omaha
Landing craft and ships unload troops and supplies at Omaha Beach a few days after D-Day. (Photo: Conseil Régional de Basse-Normandie / US National Archives)

What is D-Day?

Landing craft and ships unload troops and supplies at Omaha
Landing craft and ships unload troops and supplies at Omaha Beach a few days after D-Day. (Photo: Conseil Régional de Basse-Normandie / US National Archives)

It was the largest invasion ever assembled, before or since, landed 156,000 Allied troops by sea and air on five beachheads in Normandy, France.

D-Day was the start of Allied operations which would ultimately liberate Western Europe, defeat Nazi Germany and end the Second World War.

We’ve compiled a list of frequently-asked questions about D-Day. We hope that you will visit The D-Day Story to find out more about it.

  • Why is the term ‘D-Day’ used?
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    PreparationD

    When a military operation is being planned, its actual date and time is not always known. The term ‘D-Day’ was therefore used to mean the date on which operations would begin, whatever date that was. The day before D-Day was known as ‘D-1’, while the day after D-Day was ‘D+1’, and so on. This meant that if the date  changed all other dates in the plan did not have to be corrected. The armed forces also used the term ‘H-Hour’ for the start time.

  • What was the Battle of Normandy and when did it take place?

    The Battle of Normandy is the name given t o the fighting in Normandy from D-Day until the end of August 1944. The liberation of Paris on 25 August 1944 is sometimes used as the end point of the Battle of Normandy.

  • What was Operation Neptune and when did it take place?

    The armed forces use codenames to refer to military operations. Operation Neptune was the assault phase of Operation Overlord and involved landing the troops on the Normandy beaches. It began on 6 June 1944 (D-Day) and ended on 30 June 1944. By then, the Allies had established a firm foothold in Normandy.

  • What was Operation Overlord and when did it take place?

    The armed forces use codenames to refer to military operations. Operation Overlord was the codename for the Allied invasion of north-west Europe. Operation Overlord began on 6 June 1944 (D-Day) and continued until Allied forces crossed the River Seine on 19 August 1944.

  • How many Allied ships were involved in D-Day?

    Operation Neptune, including D-Day, involved huge naval forces, including 6,939 vessels: 1,213 naval combat ships, 4,126 landing ships and landing craft, 736 ancillary craft and 864 merchant vessels.

  • How many Allied aircraft were involved in D-Day?

    On D-Day 11,590 Allied aircraft were available to support the landings. They flew 14,674 sorties and 127 were lost. The airborne landings on both flanks of the beaches involved 2,395 aircraft and 867 gliders of the RAF and USAAF.

  • How many Allied troops were involved in D-Day?
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    D-Day & Battle of NormandyD

    On D-Day, the Allies landed around 156,000 troops in Normandy. 73,000 American (23,250 on Utah Beach, 34,250 on Omaha Beach, and 15,500 airborne troops), 83,115 British and Canadian (61,715 of them British) with 24,970 on Gold Beach, 21,400 on Juno Beach, 28,845 on Sword Beach, and 7,900 airborne troops.

    By the end of 11 June 1944 (D+5) 326,547 troops, 54,186 vehicles and 104,428 tons of supplies had been landed on the beaches.

  • Which Allied nations took part in the fighting?
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    Family historyD

    The majority of troops who landed on the D-Day beaches were from the United Kingdom, Canada and the US. However, troops from many other countries participated in D-Day and the Battle of Normandy: Australia, Belgium, Czechoslovakia, Denmark, France, Greece, the Netherlands, New Zealand, Norway and Poland.

  • What does the ‘D’ stand for?

    The ‘D’ does not stand for ‘Deliverance’, ‘Doom’, ‘Debarkation’ or similar words. In fact, it does not stand for anything. The ‘D’ is derived from the word ‘day’. ‘D-Day’ means the day on which a military operation begins. The term ‘D-Day’ is still used for military operations, but to the general public it is generally used to refer to the Allied landings in Normandy on 6 June 1944.

  • How many people were killed on D-Day and in the Battle of Normandy?

    The number of people killed in the fighting is not known exactly. Accurate record keeping was very difficult under the circumstances. Books often give a figure of 2,500 Allied dead for D-Day. However, research by the US National D-Day Memorial Foundation has uncovered a more accurate figure of 4,415 Allied personnel killed on D-Day. These include 2,501 from the USA, 1,449 British dead, 391 Canadians and 73 from other Allied countries. Total German losses on D-Day (not just deaths, but also wounded and prisoners of war) are estimated as being between 4,000 and 9,000. Over 100,000 Allied and German troops were killed during the whole of the Battle of Normandy, as well as around 20,000 French civilians, many as a result of Allied bombing.

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