BOSTON ( TheStreet) -- Talk of stretching dollars and pinching pennies may not translate into actually being mindful of your money. According to new study by credit-card company Visa ( V), U.S. consumers lose track of up to $2,500 a year.

The average survey respondent couldn't account for $21 a week in cash spending, adding up to more than $1,000 a year. Younger adults, those between the ages of 18 and 24, claim to lose track of $2,500 annually.

Asked to guess where they were spending the unaccounted cash, 34% speculated it was used for purchasing food and groceries. Shopping for "non-essentials" was cited by 32%. Dining out and "enjoying a night on the town" combined as the likely culprit for 57% of those who took part in the study.

"Even for the most organized spender, it can be tough to keep track of every cup of coffee, greeting card, teacher's gift or stocking stuffer picked up at the mall and paid for with cash," says Wayne Best, Visa's chief economist.

The U.S. isn't alone when it comes to budgetary amnesia. Consumers around the world report they are unable to account for 20% of their cash spending each week. Visa polled 12,000 adults in the U.S., Canada, India, Russia, South Africa, Australia, South Korea, Mexico, Brazil, Argentina and Japan.

Australians reported the largest cash disappearance, both in terms of actual amount lost ($59) and percentage of total spent (34%). Adults in India reported losing track of $8 each week, or 31%. Compared to 12 months ago, Russia (38%) and India (74%) believe they are losing track of more money at a significantly higher rate than U.S. consumers do (13 percent).

Visa said, unsurprisingly, that debit cards are a good tool to track spending.

Since April 2009, spending on Visa-issued debit cards surpassed spending on its credit cards. Debit cards currently make up about 70% of Visa's U.S. transactions, and the company has issued more than 352 million cards. Rival MasterCard ( MA) has more than 211 million debit cards in circulation.

As part of the Visa survey, Americans, whose payment method of choice is a debit card, claimed that they would rather give up coffee, MP3 player, mobile phone, email, visiting social network sites -- and even cash -- for one week than they would their debit card.

-- Reported by Joe Mont in Boston.