The True Cost of a Personal Loan: A Worked Example, Beginning to End

The offer

SoFi quotes us $25,000 at 9.99% APR for 60 months, with autopay applied. No origination fee. No prepayment penalty.

Monthly payment: $531.18. Total payments over 60 months: $31,871. Total scheduled interest: $6,871.

That's the disclosed math. Now let's add everything else.

Line item 1: Interest paid

$6,871 over 60 months. This is the headline cost — the dollars you transfer to SoFi above and beyond the principal you received. Out of pocket.

Personal loan interest is not tax-deductible for personal-use borrowing (unlike mortgage interest in some cases, or HELOC interest used for home improvement in some cases). The full $6,871 is real, after-tax money.

Line item 2: Fees

$0. SoFi has no origination fee, no application fee, no prepayment penalty, no annual fee. This is the strongest argument for SoFi specifically: every dollar you pay above the principal is interest, nothing more.

For a fee-charging lender, this line item could add $500–$2,000 (origination), plus any late fees ($25–$45 each, when triggered).

Line item 3: Application time

90–120 minutes. Realistically:

• 30 minutes of pre-application research (which lender, what term, what amount)
• 15 minutes of soft-pull prequalification at SoFi
• 15 minutes of soft-pull at one or two competitors for comparison
• 30 minutes of the formal SoFi application after you accept the quote
• 15 minutes of identity verification, document upload, and review

If your time is worth $50/hour after taxes, that's $75–$100 of "cost" in time. Real but small.

For borrowers with messier financial profiles (self-employed, irregular income, recent move), application time can balloon to 4+ hours.

Line item 4: Hard credit pull

The hard pull dings your FICO by 5–10 points temporarily. Cost depends on what else you're applying for in the next 12 months. If nothing, the impact is essentially zero. If you're applying for a mortgage in 6 months, this could cost you $50–$200/month in mortgage interest at the margin if it pushes you to a worse rate tier.

For our example: assume nothing else is in motion. Cost: $0–$50.

Line item 5: Opportunity cost — the big one

The $531.18 monthly payment, over 60 months, totals $31,871 of cash outflow. If you weren't making this payment, what would you do with the money?

Scenario A: Invest in a low-cost index fund at 7% real return.

• $531/month invested at 7% real for 60 months → about $38,150 of accumulated value
• Of that, $31,871 is your contributions and $6,279 is growth.
• You're foregoing $6,279 of investment growth to make these loan payments.

Scenario B: Pay off other debt at 22% APR (e.g., credit cards).

• $531/month against 22% credit card debt would pay off ~$28,000 of card balance over 60 months
• Net interest savings: ~$15,000 vs. minimum payments
• Foregoing that to pay 9.99% on a personal loan is a worse trade.

Scenario C: Spend it on consumption.

• No financial opportunity cost — the alternative would be to consume more.
• But this is usually the implicit reason people take personal loans: they want to consume now and don't have the cash. The "opportunity cost" of paying back the loan is just having less to spend over the loan's life.

For our worked example, assume Scenario A: you'd otherwise be investing in a 7% index fund. Opportunity cost: ~$6,279.

Line item 6: Comparison to the alternative

What would you have done if you didn't take this loan?

Alternative 1: Used credit cards. At 24% blended APR, the same $25,000 borrowed would cost ~$13,200 in interest over the equivalent 60 months. SoFi's $6,871 is a $6,329 savings vs. cards.

Alternative 2: Used HELOC. Maybe 8.5% APR, $400 in closing costs. Total cost ~$6,030. Slightly cheaper than SoFi by ~$840, but with a 6-week origination timeline and risk to your home.

Alternative 3: Delayed the spend. If you'd waited 12 months and saved $25,000 cash, you'd have paid no interest at all — but you'd have given up 12 months of whatever the spending was for.

Alternative 4: Drained savings. Pay cash from emergency fund. Saves the interest but eliminates the buffer; if a real emergency hits, you're back at the cards.

For our worked example: assume Alternative 1 (credit cards). The personal loan saves $6,329 vs. cards.

The full ledger

Line	Cost	Note
Interest paid	$6,871	After-tax, non-deductible
Fees	$0	SoFi advantage
Application time	$100	At $50/hr labor cost
Credit pull impact	$0–$50	Depends on near-term plans
Opportunity cost (vs. investing)	+$6,279	If you'd otherwise invest at 7%
Gross economic cost	~$13,300	Over 60 months
Savings vs. credit cards	−$6,329	If cards were the alternative
Net economic cost (vs. cards alternative)	~$6,971	The "should I" answer

What this tells you

If your alternative was credit cards or a higher-APR loan, the $6,971 net economic cost is dramatically better than the alternative — the personal loan is the right call.

If your alternative was a HELOC at meaningfully lower rates, the personal loan is slightly worse (~$1,000) but more flexible.

If your alternative was waiting and saving, the personal loan costs you ~$13,300 of total economic cost over 60 months for the privilege of having the money now.

If your alternative was investing the money instead of spending it, you're effectively paying $13,300 to consume now instead of building wealth. This isn't always wrong — sometimes consuming now (a needed home repair, a medical emergency) has its own value. But it's worth seeing the number explicitly.

The takeaway

The "cost" of a personal loan isn't just the interest line. It's the interest plus fees plus opportunity cost minus the savings vs. your real alternative. For most borrowers most of the time, the personal loan looks worse than the headline interest number suggests, but better than the cards-or-HELOC comparison would imply.

Always do the full ledger before signing. The 30 minutes you spend on it is the most valuable financial planning of the entire process.