How should I invest/spend this 50k inheritance?

You've got a great emergency fund built up and no credit card debt. That's something to be proud of. If you didn't already have those two things taken care of, that would be your first priority.

If I were in your situation, I would pay off the student loan. Yes, it's a low interest rate, but you've got the opportunity to pay it off completely and eliminate a monthly payment from your life. Take it.

I don't know if you've already contributed to your Roth IRA for this year or not, but I would set aside $11,000 to cover the max contribution to your Roth IRA for this year and next year.

That leaves about $10,000 left. Do you have any money set aside for your next car? If not, allocate most of this money toward your next car. When you need to buy another car, you will be able to pay cash and avoid a car loan.

I would first get rid of the student loan. This will leave you with 11K. I would then use this to fund your ROTH. If you are married you can put up to 5K per year each.

For any money left over, I would open a regular (not tax advantaged) mutual fund. You can contribute half the money you were paying toward your student loans, and the other half can go to your mortgage.

Also I would look at doing a refi on your house. You might be able to move a 10 or 15 year at your current mortgage payment.

Others have suggested paying off the student loan, mostly for the satisfaction of one less payment, but I suggest you do the math on how much interest you would save by paying early on each of the loans:

1. You didn't say how many years you've got into each of these loans or what was the original loan balance, but doing some rough guesses (e.g. on http://www.bankrate.com/calculators/mortgages/amortization-calculator.aspx) you could easily be paying $600 per month in interest on your mortgage. If you apply the 50K to the mortgage and jump down a few years in the amortization schedule, now you're paying $475 per month in interest (again these are just guesses because I don't know the full details on your loan). Even though your payment didn't change, that extra $125 is now going toward the principal and thus building your equity & net worth.
2. Do the same calculation with your student loan balance. How much interest will you be paying for the remainder of the loan and how does that compare with your calculations in step 1 for the mortgage over the same time period?

When you do the calculations I think you'll see why paying toward the debt with the highest interest rate is almost always the best advice.

Whether you can refinance the mortgage to a lower rate is a separate question, but the above calculation would still apply, just with different amortization schedules.

You mention only two debts, mortgage and student loan, but you mention $19K in savings, which suggests that you are a saver, and likely do not have other debts.

You did not mention your (net) income and expenses (income statement), but since you have substantial savings, you likely live within your means (income > expenses). Since you mention $38K in retirement, we might conclude you are regularly saving for retirement (are you saving 10% toward retirement)?

You did not mention any medical condition or other debts, that might require a large savings, so I would suggest having 6 months savings ($2.5K x 6 = $15K) but should your net expenses be less, you might reduce this ($2K x 6 = $12K).

You do not mention any investment you might want to make, but since you did not mention any candidate investments, we can assume you have no (specific) investments you find particularly attractive. You did not mention anything you were saving to purchase that you might want to purchase.

You have combined $19K + $50K = $69K savings, and $15K would be a comfortable emergency savings, leaving $54K you could use to reduce mortgage or student loan debt.

The mortgage debt interest @4.5%, is higher, so paying that debt off would be like earning 4.5% guaranteed return on your money, tax-free. At your income, your marginal tax rate is low enough that the mortgage interest deduction (if you do itemize) would not reduce this return much (15% if you itemize).

The student loan debt interest @2.8%, would be like earning 2.8% guaranteed return on your money, tax-free.

Clearly the higher return on your 'investment' in paying off debt would be reducing your mortgage balance (over 50% higher return on investment, compared to the student loan debt).

You did not mention any circumstance that might cause the student loan rate to increase, the mortgage rate to increase, nor did you mention any difficulty making both the mortgage and student loan payments, the amounts of either payment, nor the number of years remaining to pay on either.

Should you need (or desire) to reduce your payments, you could choose to payoff the student loan to eliminate one payment, and thus decrease your expenses. Or you could choose to pay down the mortgage, and refinance (or refactor) the mortgage to obtain a smaller payment. Another strategy (assuming you have had your house for 5-7 years), might be to pay the mortgage down enough to refinance into a 15 year loan, and (assuming you have a good credit score) obtain a lower (3%) rate.

But I am going to suggest you consider a blended approach. Combine the Dave Ramsey Debt Snowball approach with the reduce the interest rate approach. Take the $54K ($57K?) available (after reserving 6 months emergency fund), and split between both. You pay your mortgage down by $27K and your student loan debt down by $27K. Your blended return on investment is (2.8+4.5)/2 = 3.65%, and you have the following

Balance Sheet:

Assets:

• House $202K
• Savings $15K
• Roth $38K

Debts:

• Mortgage $100K @4.5%
• Student Loans $2K @2.8%

The next steps would be to,

• Focus on paying off the student loan and then use the money freed from that payment to payoff your mortgage.
• Consider refinancing into a 15 year loan for the lower interest rate.
• Consider whether a slightly smaller emergency fund ($13K) and paying off the remaining student loans ($2K) would leave you with a comfortable emergency fund. (Note that if your student loans are $300/month, the additional depletion of emergency fund would be offset by the reduction in amount of emergency fund needed over 6 months).

There are two great reasons for paying off the student loan debt. One is the Dave Ramsey Debt Snowball approach which is that this is the smaller debt, and thus represents a psychological win, and the other is that student loan debt has special treatment even in bankruptcy.

I wouldn't recommend paying off the debts. Both are low-interest tax-deductible loans that you've been handling well enough to have significant savings, and you can likely earn a higher interest rate by investing than you could by paying down the debt. Putting your money into vanguard ETFs or a betterment account will likely be better in the long run.

When considering whether to pay off the student loan, note that, because you work for a non-profit, some or all of that debt may be forgiven after 10 years under the Public Service Loan Forgiveness Program.

I would also like to be slightly contrarian on the main question. I like having lots of savings and little debt as much as the next person. But, unless you have been planning your life with the expectation that you would receive this bequest, it is a windfall. If you weren't already doing an excellent job of saving for emergencies and retirement, or had a lot of consumer debt, I'd say you should use the money to stabilize your finances before doing anything else. But your finances do seem stable. So take some of the windfall and do something nice with it. Travel to the ancestral home of your late grandmother. Endow a small scholarship in her memory. Buy some small luxury that you could never manage on your own salary. I'm not suggesting you spend it all, but using 20% of it on something otherwise out of reach will give you good memories while still leaving you materially better off.

Saving for the future is important. Paying off debt is important. Enjoying life when you can is also important. Balance is everything.