If you're self-employed, even part-time, you might benefit from getting a business credit card. The most obvious perk of using one is that it lets you separate out your work expenses. But business cards also offer high credit limits, additional cards for employees and rewards geared towards how small-business owners spend money.
Some are better than others, though. While many promise substantial sign-up bonuses, others require steep annual fees.
To determine which card offers the best deal overall, CNBC Make It looked at 20 popular options. We considered a wide range of factors, including rewards, ease of use and perks, as well as downsides such as interest rates and fee structures.
Based on our analysis, here's our No. 1 pick, as well as some other choices that may better suit your situation.
The Chase Ink Business Preferred is our No. 1 pick overall mostly because of its wide array of rewards and large sign-up bonus. Users get 3 points per dollar on travel, shipping, advertising and internet, phone and cable services (up to $150,000 in purchases per year), plus 1 point on all other purchases.
If you manage to spend $5,000 in your first three months with the card, you're rewarded with 80,000 points.
What makes this card special is the potential value of those points: They're worth 25 percent more when redeemed towards travel through the Chase Ultimate Rewards Portal. So 80,000 points is worth $800 in plain cash or $1,000 on travel — and potentially even more if you transfer the points to a partner rewards program.
The annual fee, meanwhile, is relatively low: just $95 per year.
As for perks, the card covers up to $600 in cell phone damage or theft protection three times per year, and cardholders can add employees to the account for free. The variable annual percentage rate is 17.74 to 22.74 percent, based on your creditworthiness.
At a glance:
The Spark Cash for Business offers the highest flat-rate for rewards among business cards. Users receive 2 percent cash back on all purchases, and that's unlimited, which makes this card especially useful for big spenders who don't want to worry about categories.
Cardholders who spend $5,000 in the first three months also receive a $500 cash bonus. If you sign up now and manage to spend $50,000 in the first six months, you get another $1,500.
There's no annual fee the first year but afterwards it's $95. The variable APR is 18.74 percent.
At a glance:
If you're looking for a card with no annual fee, the SimplyCash Plus Business Card may be your best option. Users get 5 percent back at office supply stores and on wireless phone services in the U.S., plus 3 percent back in the spending category of your choice. You can go with something like gas or restaurants, or you can pick a category that best suits your business, like advertising purchases or car rentals.
For the bonus, you get $250 if you spend $5,000 on purchases in the first six months and an additional $250 if you spend $10,000 more in the first 12 months.
There are a number of perks, including travel insurance, purchase protection and exclusive pre-sale ticket offers for certain events. Cardholders also get expanded buying power, meaning you can spend beyond your credit limit without being penalized as long as you pay your bill on time. The APR is 14.24 to 21.24 percent but, for purchases, you get nine months of no interest. That makes this card a good choice if you need to borrow money for a limited time. There's no introductory offer for balance transfers.
At a glance:
With the Business Platinum Card from American Express, you and your employees get deluxe travel benefits. The card offers access to the American Express Centurion lounges as well as Plaza Premium lounges through the Global Lounge Collection, plus Delta Sky Club access when you fly with Delta. Cardholders also receive up to $200 per year in annual airline credits, which you can use to check a bag or purchase in-flight refreshments.
Free nights and other benefits via the American Express Fine Hotels & Resorts program are available too. Cardholders qualify for Gold elite status with Hilton and Starwood hotels.
The card requires a hefty $450 annual fee, though, and $300 per year for employee cards.
For rewards, the card offers 5 points per dollar spent booking hotels and airlines with American Express Travel and 1 point on all other purchases. When you make a purchase that exceeds $5,000, you get 50 percent more points, so you earn 1.5 points per dollar instead of just 1 point. That bonus lasts until you get 1 million extra points in a year.
After you sign up, if you spend $10,000 in the first three months, you receive 50,000 bonus points. Or, if you spend a total of $20,000 in that time frame, you get an additional 25,000 points. That's worth a total of $750 toward travel or gift cards.
There's another way to rack up points, too. When you redeem points through American Express Travel on a business or first class seat, or any fare class on a single airline of your choice, you receive 35 percent of those points back. That offer stands until you earn 500,000 points back that way in a year.
The Business Platinum card is technically a charge card, which means you have to pay off your balance in full each month or you'll be hit with a late fee. If you want to have the option to carry a balance, you have to enroll in the card's Pay Over Time feature.
At a glance:
It's not all that difficult to qualify for a business card, since the definition of "business owner" these days can be broad. Most credit card issuers will accept your application whether you run your own bakery, freelance or even just sell items online.
If you do qualify, note that you'll usually need to sign a personal guarantee, which ensures that you are liable for what you spend even if you go out of business. And, unlike a typical consumer card, many business cards aren't covered by consumer protection laws. That means they may tack on hidden fees and hit you with high interest rates.
So do your research and read the fine print before you decide on the card that's right for you, or whether a business card is right for you at all.
To determine which business cards offer the best deals, CNBC Make It compiled a list of 20 popular business credit cards. We vetted each card based on its reward offers, introductory and eventual APR, annual fee, bonus, recommended credit score, late fee, balance transfer fee, foreign transaction fee, redemption rates, transfer options, customer reviews and extra perks.
The main criteria in our ranking was how much each card will end up earning you in rewards relevant to businesses. To figure this out, we compared rewards structures under the assumption that a business owner would spend the same amount in each category — that, for example, they'd spend just as much on advertising as they would on shipping.
Through this analysis, we found that the Chase Ink Business Preferred would save the average business owner the most, which is largely why it came out on top as our No. 1 choice. Put simply, it has the widest array of high-earning spending categories.
It offers 3 points per dollar spent on travel, shipping, advertising, and internet, phone and cable services. The travel category includes spending on flights, hotels, car rentals and even taxis. And when you redeem the points you earn towards travel, rather than cash, they're worth 25 percent more. Effectively, that means, if points are redeemed for their maximum value, each of those categories is rewarded with 3.75 points per dollar.
Spending categories are not really equal in value, of course: Business owners will utilize some more than others. If you spend a lot of money at office supply stores, the SimplyCash Plus might be a better choice for you than the Ink Business Preferred, since it rewards office supply spending with 5 percent back, whereas the Ink Business Preferred only rewards office supply spending with 1 point.
That's why we also weighed reward structures against other factors, such as bonuses, annual fees and perks. And we considered reward limits, since many business owners spend hundreds of thousands of dollars every year.
For the largest return, you should find a card that rewards how you spend money for your business.
Co-branded business cards did not make our final list due to their often complex reward systems and potential to limit your travel options to a specific brand. But these cards are certainly worth considering for brand-loyal business travelers.
Don't miss: The credit cards with the best sign-up bonuses
Like this story? Subscribe to CNBC Make It on YouTube!