The cost to mail a letter or package will increase Monday and although the price hikes are measured in cents, they will have a cumulative impact on Hawai'i's small businesses.

A first-class stamp will increase to 41 cents from 39 cents, and rates for parcels and larger packages also will go up. The U.S. Postal Service also has changed how it calculates fees, basing them on the size of a package, not just its weight.

These changes are expected to cause some confusion among businesses and regular customers come Monday. It also will increase the cost of doing business.

Jerri Lum, account manager in sales for the postal service, said these are the most changes in the rate structure in the 20 years that she's been with the service.

To help alleviate the confusion, the postal service will have employees in the lobbies of the larger post offices Monday to explain the changes. Consumers also are encouraged to visit www.usps.com/prices for information on the increases.

Janlee Mau, a USPS small-business specialist, also will be available to business owners with questions about the new rates and policies. Mau, who can be reached at 423-3937, said she'll explain how a business can save money even with the increased rates.

Many businesses are busy calculating the impact the rate increases will have. For most, the higher cost to ship and receive items will either be absorbed by the business or passed on to the customer.

Tony Yamada, a partner in Ideal Collectables, said his company's sales are primarily done over the Internet, meaning 90 percent of his products are shipped off-island. Yamada said his company will pass on the added postal costs to the customers, but he is aware of a possible backlash.

"One of the reasons the Internet was so great was it gave people the opportunity to shop online anywhere at any time," Yamada said. "But it seems that every other year the rates are increasing for UPS, FedEx and the U.S. Postal Service, so what once was a bargain to shop on the Internet, now sometimes you might be able to get it cheaper at your local store. So it definitely will affect our business online."

Tim Lyons, executive director of the Hawai'i Business League, said there are so many costs involved in running a business that many owners may not adjust prices right away.

"Most businesses will keep a mental track of those kind of increases so when they have enough of those things they will post a price increase," Lyons said. "In the meantime, they wind up eating the costs."

Sam Slom, a state senator and president of Small Business Hawai'i, said business owners have been slow to use computer technology, but that the rising costs of doing business will force owners to become more Internet savvy.

"More and more companies are doing their invoicing by e-mail and that will accelerate," Slom said. "At 41 cents per piece first-class and you're sending out a thousand billing pieces a month, that's a big difference."

Slom's Small Business Hawai'i puts out a monthly newsletter that is mailed and also is featured on his Web site. Slom said he will "take a hard look" at the cost of mailing the newsletter to see if it's economically feasible.

Allison Takeshita sells her Grumpy Girl products primarily online and has calculated the impact of the postal increase: The cost to ship a one-pound package will increase by 14 percent and a two-pound package by 24 percent, while the rate for her popular bird poop cleaning kit will go from $6.05 to $7.50.

"It's kind of hefty," Takeshita said of the increases.

She said customers feel that one of the incentives of online shopping is discounted or free shipping. But she said she can't see many businesses absorbing all of the postal rate increase.

Takeshita said many customers would rather pay for an increase in a product's price than a hike in shipping fees. She said she isn't sure how much of the increase she will pass on to her customers.

"I think it's a psychological thing," she said. "Right now my rate is $4.50 for a one-pound-or-less order. To change it 50 cents might not be bad, but once you get to a certain amount, like $7 or $8 for a small order, people start to get turned off. If I changed product cost a dollar, I don't think people would mind that that much."

Reach Curtis Lum at culum@honoluluadvertiser.com.