Check your cupboards! That Lego set that’s been sitting in there since your kids moved on to playing with something else might actually be worth more than you paid for it.

I first found out about the world of Lego investing years ago from an ex-boyfriend, who’s car couldn’t fit in his garage due to the large Lego train set and surrounding city he had created in it. Now, he hadn’t sold anything, but had paid large sums of money on his Lego habit and even larger sums for retired sets off sites like eBay. Now, I won’t go into any more detail about that relationship, but the Lego thing had me curious.

There is a great wide world of Lego collectors (and kids and adults that just like to play with it) that has turned the humble Danish brick toy into collectors items and, with the right set, a legitimate investment opportunity. Some Lego sets, never opened and kept in excellent condition, have appreciated in value by over 10% every year. There’s not many investments that will give you that! Even some second hand sets can be resold for more than you bought them for.

Now, not every set will go up in value, and you do need to have the right set to make any money, but it is definitely something to look at if you’ve got any Lego sets lying around in the cupboard (Hint: If you have Star Wars sets, especially the big ones, they are very popular). You will generally also need to have the box, and the instructions to create a complete set for sale.

Inspired to find all the Lego in the house? Brickpicker is one site that can give you an approximate value of the sets, BrickInvesting is another. You can search by set number or just browse to find the one you have.

Some top performing Lego sets

Death Star II: This 2005 set retailed for $600 but is now worth $2000 new or $1300 used.

Millennium Falcon: The large Millennium Falcon would set you back $980 in 2007, but you can now get over $3500 for a used one and a new one has sold for as much as $6400!

Creator House: One of the Creator Houses (set 4956 for those of you playing at home) cost $49.99 in 2007, its value is now double that at $100 for a used set and up to $200 for one new in box.

Hogwarts Express: There are a number of sets of the Harry Potter train over the years but the 2004 version (set 4758) is now worth $120 new and $89 used, that’s after a $40 investment back when it was released.

Things to remember

Limited edition and seasonal sets do better in the secondary market. Like most things, the rarer the more valuable.

Most of the top performing sets were released after 2000.

If you are going to open the box (do it very carefully) and build the set, keep the box, instructions and pieces in excellent condition. Save all the components and store them well. The better the condition, the more the set may sell for later.

Stack boxes like books, vertically instead of horizontally as boxes can crush if stacked on top of each other, which will decrease any value.