It used to cost her around $25 to fill up her Toyota Corolla. She’s spent closer to $40 since the Iran war began and pushed up the average U.S. price for a gallon of regular gasoline by $1. Sherman-Shafer, a retired dental office assistant who picks up Uber passengers five days a week, said she’s putting in extra hours to cover the difference.

“We don’t get reimbursed for gas. We rely on the generosity of the tip,” Sherman-Shafer said. Some passengers have tipped more to compensate for higher gas prices, but most don’t tip at all, she said.

Driving a car, van or truck is a big part of many Americans’ workdays. Nearly 27% of civilian workers cited driving as a physical demand of their jobs last year, according to the U.S. Bureau of Labor Statistics. Millions of drivers use personal vehicles for their work, from delivery and ride-share providers like Sherman-Shafer to self-employed electricians, nannies, home health care aides and real estate agents.

As the war enters a fifth week and continues to disrupt global oil supplies. many of those workers are now scrambling to make ends meet. The national average price for gas reached $3.99 per gallon on Monday, up 34% from a month earlier, according to AAA.

“With everything going up, it’s impossible to save a dime,” Sherman-Shafer said.

Some companies compensate employees for using their own vehicles, including the cost of gas. In the U.S., the Internal Revenue Service sets a standard mileage rate every year that businesses and private contractors can use to calculate tax deductions. Alpine Maids, a housekeeping company based in Denver, pays cleaners the 2026 federal reimbursement rate of 72.5 cents per mile for the distance they drive to clients’ homes.

But with gas prices spiking, that money is not going as far, said Chris Willatt, a former geologist who now runs Alpine Maids.

“Our maids drive their own cars, so it’s kind of like their paycheck got smaller,” Willatt said. “They’re all upset.”

Willatt said he reduced how often maids must report to the office, from daily to once a week, and rejiggered cleaning assignments so employees aren’t driving as far between clients. If gas prices climb further, he said he might increase what he charges customers so he can pay workers more.

Molly Kenefick, the owner of Doggy Lama Pet Care Inc. in Oakland, California, said she recently raised her gas reimbursement rate to 80 cents per mile for 15 employees who use their own vehicles to pick up dogs and take them for hikes around the Bay Area. The rate increase will stay in place until gas prices in their area drop below $5 for at least a month, she said.

Kenefick said she planned to raise prices for the company’s services in May. But she doesn’t want to increase them too much because she’s worried she’ll lose clients. So Kenefick is also dipping into her savings to pay for gas.

“The economy is hard for people. Everybody’s under strain,” she said. “I can take some of the load and the company can take some of the load, provided this doesn’t go on too long.”

Ride-hailing and food delivery platforms that rely on gig workers don’t reimburse drivers for gas, but some are offering temporary incentives in response to rising gas prices. DoorDash, Uber, Lyft and Instacart are providing more than the usual cash back on gas purchases for drivers who use company-branded debit cards. DoorDash and Instacart are giving a weekly fuel payment to drivers who travel 125 miles or more making deliveries.

Sarah Noell, who spends about 20 hours a week making deliveries for DoorDash in Lynchburg, Virginia, said the measures help somewhat. But she said she’s noticed more customers declining to add tips to their orders as gas prices have increased.

Noell has started refusing any order that won’t average out to $1 per mile, including the $2.50 per order she gets from DoorDash. That cancels out many users who aren’t tipping or give only small tips.

“It takes nearly double the cost to fill my tank,” Noell said. “Ten dollars used to get me a decent amount. Now it only gets me 3 gallons.”

Owners of diesel-powered vehicles have seen even steeper fuel price increases since the war started on Feb. 28, affecting drivers around the world.

Drivers of diesel-powered “jeepneys” in the Philippines, went on strike for two days last week to protest their higher costs. In France, dozens of buses and trucks drove slowly on the Paris ring road Monday to demonstrate their concerns about rising diesel prices. Drivers and businesses want the French government to provide aid to mitigate the impact.

“The major difficulty right now is finding our balance on our business since we sold services with the vehicles at a certain price for diesel that was much cheaper. And we’re not going to ask customers to pay that difference,” Sarah Bahezre, manager of the bus transportation company Ulysse Cars, told The Associated Press.

Average U.S. diesel prices climbed 44% over the last month, according to AAA.

A few weeks ago, Rachel Hunter paid $3.62 a gallon to fill the single diesel truck used by Cactus Crew Junk Removal & Thrift Store, a Phoenix business she and her husband co-founded. The same fuel now costs $6.09 per gallon in Phoenix, according to AAA.

The truck carries all kinds of heavy cargo, from slabs of solid maple bowling lanes to loads of concrete paver tiles. So fuel costs quickly add up, Hunter said, particularly with a truck that only gets 12 or 13 miles to the gallon.

Hunter has started quoting prices that reflect the jump in prices. She worries she’s in a “vicious circle” that could hurt the business if oil prices remain high.

“We don’t want to get a bad name for being overpriced,” she says. “I’ll be able to explain it where people can understand, but it doesn’t mean they can afford it.”