Despite a fifth (19%) of grandparents surveyed living more than 100 miles away from their grandchildren, the research for the Co-op found they are set to shower them with gifts.
Grandparents said they would spend £59 per grandchild on average, and with those surveyed typically having four grandchildren, the total cost amounts to £236.
One in 10 (10%) grandparents surveyed plan to spend £100 per grandchild.
Around 15% of grandparents said they will spend more on their grandchildren than they did a year ago, with common reasons being that their grandchild had asked for a more expensive gift and that they had helped to look after their grandchildren this year.
Some 14% said they spend different amounts on their grandchildren at Christmas, depending on how old their grandchild is, how often they see them and how easy they are to shop for.
A further 14% said they struggle to buy presents for their grandchildren as they already have so much.
James Antoniou, head of wills at Co-op Legal Services, said: "It's good to see that grandparents are becoming increasingly generous towards their grandchildren."
Some 500 grandparents took part in the survey.