• A new survey finds 47% of adults currently have at least one unused gift card, voucher or store credit.
• The average unused amount is $175 per person, up from $116 last year.
• Amid record high prices, those sums may provide a welcome boost to consumers' wallets.

Even as many people struggle to stretch their incomes amid high inflation, it turns out there's money they already have they're probably overlooking — unused gift cards.

To that point, 47% of people currently have at least one unused gift card, voucher or store credit, according to a new survey from CreditCards.com.

The average unused amount is $175 per person, up from $116 last year. For the entire U.S. adult population, that may add up to $21 billion, CreditCards.com estimates.

Amid record high prices, those sums may provide a welcome boost to consumers' wallets.

"It's like finding that $20 bill in that jacket pocket from last winter," said Ted Rossman, senior industry analyst at CreditCards.com. "But in this case, it's even more money than that."

Holding onto gift cards can be a losing proposition for multiple reasons, Rossman said. The value of the unused sums could go down because of inflation. You may lose the card or get charged inactivity fees. Or the store may go out of business.

"There's really no good that comes from letting these lie around," Rossman said.

How to make the most of unused gift cards

Ideally, consumers may find ways to put the unused gift cards to use in ways they will personally enjoy.

But if you can't think of anything you want, there are other ways to put the cards to good use, Rossman said.

Take inventory of the unused gift cards you have and upcoming events like birthdays and holidays. You may be able to buy gifts for friends or loved ones using those balances.

Alternatively, you may opt to resell your gift cards with companies like CardCash, Raise or ClipKard, Rossman suggested.

However, it's important to note those services may only honor part of the value, typically 70% to 80% of the original sum.

Most gift cards no longer expire. For those that do, regulations generally prohibit them from doing so before a five-year period, according to Rossman.

Still, businesses may charge inactivity fees that eat into a gift card's original value. Plus, stores or restaurants may go out of business, rendering the sums useless.

"My advice would be to use them, because they're not going to be more valuable over time," Rossman said.

Who has the most money in unused gift cards

Of the 2,372 adults who participated in the online survey in July, millennials were most likely to have unused gift cards lying around, at 52%, with an average value of $226.

Next came Gen Z, of whom 51% had unused balances, with an average value of $149.

However, Gen X and baby boomer respondents are also guilty of not putting gift cards to use, with 43% and 42%, respectively.  The average unused value is $180 for Gen Xers and $133 for baby boomers.

When broken down by household income, those with between $80,000 and $99,999 were most likely to have unused gift cards, with 57%, at an average value of $227.

Respondents with incomes of more than $100,000 were next, at 56%, and an average value of $265.

Those with lower earnings were less likely to let the sums go unused. Still, 41% of those with household incomes under $50,000 reported having unused gift cards, as well as 53% of those with between $50,000 and $79,999.

The average value of unused gift cards is $128 for households earning less than $50,000 and $165 for those with incomes between $50,000 to $79,999.