Looking for a side job? Join the club. More than one-in-three U.S. workers (36%) -- that's 57 million Americans -- have picked up a side gig, according to a recent Gallup survey. But where and how do they find them?

Advancements in digital technology have created the ideal conditions for the growth of the gig economy. Third-party apps and online platforms make it easy and convenient to find work and get paid in your free time.

But with this abundance of side jobs, how can you find the right job for you? Let's take a closer look at what side gigs can offer, and how you can compare them.

What is a side job?

A side job is a job, often part-time or short-term, that you use to supplement your primary source of income. Examples include freelancing, pet sitting, delivery driving, rideshare driving, and housecleaning. Side jobs are typically easy to get into and completed on a contract basis.

Although side jobs are usually performed alongside a "day job", there are people who earn enough in the gig economy to go full-time. In fact, about 3.8% of U.S. workers do gig work as their primary profession. For the rest, the side gig can be a convenient way to supplement a full-time job.

Why are Americans flocking to gig work? The right side job can help you pay off a debt faster, improve your credit score, build an emergency savings, or save up for a vacation. Whatever your reason, a side gig can give you that extra income that you need.

Here's a quick summary of the benefits:

• Earn extra cash.
• Gain experience in a new line of work.
• Learn skills to become a more valuable employee or entrepreneur.
• Meet new people.
• Pursue a passion.
• Enjoy flexible work hours.
• Gain more freedom working as a contractor.
• Choose from many remote working opportunities.

It's clear that the right side gig can seriously improve your quality of life. But which side job is best for you?

How should you compare side jobs?

With so many options, how do you decide which side job to pursue? Here are the main factors to consider. Use the tools below to filter available side jobs until you find the best fit for your circumstances.

How do you qualify?

Are you eligible to do the job? Is it available in your state? Check the requirements to ensure that you qualify.

Qualifying may be more difficult for certain job types. For example, if the gig involves you driving, your prospective employer will have to vet you to confirm that you're a suitable driver with a qualifying vehicle.

Be sure to find out what is required to find out which side gigs are available to you.

What type of side job is it?

Next, what type of work does the job entail? You will likely have a preference when it comes to what you actually do to earn the money. Many use their side gig as an opportunity to pursue their passions or express themselves creatively. Others look for work in a field that interests them, to accrue experience and build out their resume.

When comparing side jobs, look for something that interests you and is compatible with your skillset.

What do unbiased reviews say?

You should also read real, unbiased reviews from current or past employees of your prospective side job. These reviews can give you insight into what the job will ask of you, including benefits and downsides that you might not have thought of. This is a great way to avoid pitfalls you might otherwise fall into, saving you time and money.

What are the estimated earnings of the side job?

How much can you earn? You'll want to make as much as possible in the time you can spare, so it's important that you investigate each job's compensation structure. Are workers paid hourly, or per transaction? How much can you expect to make? Ensure that you invest your time in work that will pay you a competitive wage.

What fees are involved?

Does your desired side job have any hidden costs? Will you have to pay some kind of fee to the company that facilitates the job? If a job involves a vehicle, will you be asked to pay maintenance costs? Or if you're signing up for a platform for dog walkers or babysitters, will you have to pay a subscription fee to join the network? Be sure to calculate these costs into your overall assessment.

What is the onboarding process?

Will there be onboarding costs? How long will it take to start earning? Is there a learning curve? Consider all of these factors.

If you need to start earning right away, you should pursue a job with short onboarding process and turn-around time. On the other hand, if you aren't in a rush, you may be able to earn more in the long run by choosing a job with a longer training period.

Are there opportunities for growth?

Lastly, does the job enable you to earn more money over time? Can you grow with it? Is there a future in it? Will it give you experience in a career path that you'd like to pursue?

If you are looking for a long-term growing revenue stream, this is an important factor to consider. The right side job could be the first step toward a new career.

Putting it all together

By considering these factors, you can properly vet a side job and compare jobs against each other to find the best one for your situation.

Here's a quick checklist to keep on-hand:

• Are you eligible?
• What type of work will you do?
• What do past workers say about the job?
• How much can you earn?
• Are there any costs involved?
• How long and strenuous is the onboarding process?
• Can you earn more over time or reap some other long-term benefit?

Answer these questions for each side job you consider.

Find the right side job for you

Ready to get to work? We're here to make it easy on you. Below, you can find some of the leading side job opportunities available today. In a glance, you can compare competing companies, read unbiased reviews, check earnings estimations, and compare each platform's fees.

If you'd like to learn more about any one opportunity, click on it for an in-depth review. In our reviews, we cover topics like the business type, compensation structure, expected earnings, availability, and eligibility requirements. This will provide all the info you need to find the perfect side job for your circumstances. Then, just sign up to start earning!