Now you can tell if a graduate degree will pay off

Should you go into hock to get a graduate degree? As student debt levels continue to rise to sometimes unsustainable levels, that's a question experts are increasingly attempting to answer with data.

Armed with information about 300,000 student borrowers, student loan refinancer SoFi recently plotted out the average income that real graduates earned one, three, five, seven and 10 years after obtaining advanced degrees. They considered eight subjects: humanities, nursing, engineering, pharmacy, law, business, dentistry and medicine.

The data should help borrowers do two things, said Bob Park, SoFi's head of career strategy and professional development. It can help you benchmark whether your employer is providing a market rate salary for your education level. And, by comparing how much you earn now to the average earnings of those with advanced degrees, you can rough out when you're likely to break even on the amount you spent to get that additional education.

For example, if it will require three years and $150,000 in tuition to get a law degree, you can figure your total cost of obtaining the degree by adding the tuition and fees to your lost wages for time spent in grad school. We'll guestimate lost wages for our hypothetical student at $45,370 annually, which is the average wage of a college graduate in 2014, according to the National Association of Colleges and Employers.

Add the $150,000 cost of tuition and fees to $136,110 ($45,370 x 3 years) in lost wages to find the total cost of getting a law degree: $286,110. To determine this hypothetical borrower's break-even point, we'd take SoFi's earnings data and compare it to the borrower's average wage now.

This hypothetical lawyer would find that she could expect to earn $114,000 fresh out of law school -- some $68,630 more than the $45,370 she was earning prior to obtaining the law degree. Given the 2 percent rise in average lawyer wages, this law school graduate could anticipate that her degree would pay off in about four years.

An engineering graduate, on the other hand, would get a lower bump in first-year earnings after obtaining a graduate degree. Engineers earn $69,140 on average right out of college, according to the National Association of Colleges and Employers.

SoFi's data shows an engineer would pull down $80,100 the year after attaining a graduate degree in the field -- about $11,000 annually more than he earned with an undergraduate degree alone. Unless the cost of obtaining the additional education was low, this hypothetical student is likely to find that an investment in advanced education would take decades to pay off.

Other little factoids that came out of SoFi's data: If you got an undergraduate degree in humanities or the arts, you're likely to benefit the most from getting a graduate degree. That's unless you're going after a Masters in fine arts, which may not ever pay off in increased lifetime earnings.

For those who are already pursuing an advanced degree -- or who have personal reasons for wanting one that overwhelm the simple math -- knowing what other people earn for similar levels of education can help benchmark your pay to industry norms, said Park. If you find you're earning less than average, it might be time to shop around for a new employer or negotiate a raise, he added.

So, how much should you expect to earn annually if you go back to grad school? Here are the averages according to SoFi:

Humanities: Average wage in one year $62,900; five years, $73,200; 10 years, $84,500

Nursing: Average wage in one year, $95,200; five years, $102,500; 10 years, $107,400

Engineering: Average wage in one year, $80,100; five years, $92,700; 10 years, $115,100

Law: Average wage in one year, $114,000; five years, $124,300; 10 years, $131,300

Pharmacy: Average wage in one year, $115,300; five years, $123,400; 10 years, $128,500

MBA: Average wage in one year, $105,800; five years, $120,100; 10 years, $138,400

Dentistry: Average wage in one year, $128,900; five years, $188,900; 10 years, $233,700

Medicine: Average wage in one year, $80,400; five years, $204,900; 10 years, $284,600

That said, averages mask a lot of variation. If you're a top student applying for a job in a big city where salaries are higher, you'd likely earn significantly more. And, naturally, plenty of graduates earn less, too.

Indeed, SoFi said the averages are often skewed by outlier salaries on both ends. Median incomes -- the midpoint salary -- is sometimes more representative. So, what are the median wages for those who have obtained graduate degrees, one year and 10 years out?

Humanities: One year after graduation: $52,000; 10 years: $73,000

Nursing: One year: $85,000; 10 year: $94,000

Engineering and computer science: One year: $76,000; 10 years: $107,000

Pharmacy: One year: $117,000; 10 years: $113,000

Law: One year: $115,000; 10 years: $117,000

MBA: One year: $100,000; 10 years: $110,000

Dentistry: One year: $120,000; 10 years: $211,300

Medicine: One year: $55,000; 10 years: $270,000

Editor's note: This post has been updated to reflect a data correction for "Humanities."