Personal finance
Loan Calculator
Calculate monthly payments for personal, auto, and student loans. View your full amortization schedule and see how extra payments save interest. Free, instant results.
Optional: Pay more each month to save on interest and pay off faster
Cumulative Principal vs Interest Over Time
Monthly Amortization Schedule
| Month | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $239 | $83 | $9,761 |
| 2 | $241 | $81 | $9,519 |
| 3 | $243 | $79 | $9,276 |
| 4 | $245 | $77 | $9,031 |
| 5 | $247 | $75 | $8,783 |
| 6 | $249 | $73 | $8,534 |
| 7 | $252 | $71 | $8,282 |
| 8 | $254 | $69 | $8,029 |
| 9 | $256 | $67 | $7,773 |
| 10 | $258 | $65 | $7,515 |
| 11 | $260 | $63 | $7,255 |
| 12 | $262 | $60 | $6,993 |
Showing first 12 of 36 months
How Loan Amortization Works
Amortization means paying off your loan through fixed monthly payments over time. Each payment covers both interest (cost of borrowing) and principal (reducing the balance you owe). In the early months, most of your payment goes to interest. Over time, more goes toward principal.
The formula used is M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the loan principal, r is the monthly interest rate (annual rate ÷ 12), and n is the total number of monthly payments.
Month 1
Up to 80–90% of each payment goes to interest on high-rate loans.
Midpoint
Interest and principal portions approach 50/50.
Final months
Most of each payment goes to principal. Balance drops fast.
Personal Loan Comparison
Monthly payments and total cost for a $10,000 personal loan at different interest rates and terms.
| Rate | 36-mo/mo | 36-mo total | 60-mo/mo | 60-mo total |
|---|---|---|---|---|
| 5% | $300 | $10,786 | $189 | $11,340 |
| 7.5% | $311 | $11,205 | $200 | $12,020 |
| 10% | $323 | $11,616 | $212 | $12,748 |
| 15% | $347 | $12,482 | $238 | $14,271 |
Principal + interest only. Excludes origination fees and other charges.
Loan Type Tips
Personal Loans
Best for debt consolidation, home improvements, or unexpected expenses. Unsecured, so rates depend heavily on credit score. Borrow only what you need, rates can be high for fair credit.
Auto Loans
Secured by the vehicle, so rates are lower than personal loans. Pre-approval from a credit union often beats dealer financing. Avoid 72+ month terms, you risk being underwater (owing more than the car is worth).
Student Loans
Federal loans offer income-driven repayment and forgiveness options. Private loans have variable rates and fewer protections. Max out federal aid first before considering private loans.
How Extra Payments Shorten Your Loan
Entering an amount in the Extra Monthly Payment field does not change your required minimum payment: it adds straight onto the principal portion of every scheduled payment. Because the loan balance drops faster than the original schedule assumed, less interest accrues each subsequent month, which compounds over the life of the loan.
For example, a $15,000 loan at 10% APR over 5 years normally costs about $319/month and roughly $4,122 in total interest. Adding $100 extra per month (a $419 total payment) pays the loan off in 43 months instead of 60, about 17 months early, and cuts total interest to roughly $2,891, a savings of over $1,200, because every extra dollar goes straight to principal instead of accruing future interest.
Extra payments matter most early in a loan, since that is when the interest portion of each regular payment is largest. The calculator recalculates your exact payoff date and the green summary box below the results shows precisely how many months earlier you'll finish and how many dollars in interest you'll save for the extra amount you entered.
Reading the Principal vs. Interest Chart
The stacked area chart plots two running totals across every month of your loan: cumulative principal paid (green) and cumulative interest paid (orange). Hover over any point to see the exact dollar breakdown for that month. Early on, the orange interest layer grows quickly relative to green principal; as the balance shrinks, principal takes over and the green area steepens.
The Monthly Amortization Schedule table beneath the chart backs up the visual with exact figures: how much of each month's payment went to principal versus interest, and the remaining balance afterward. It loads the first 12 months by default; click Show All to expand the full schedule, useful for longer terms like a 10-year (120-month) student loan.
How this is calculated
Method: Standard loan amortization formula
The monthly payment uses the amortization formula M = P × [ r (1 + r)n ] / [ (1 + r)n − 1 ], where P is the loan principal, r is the monthly interest rate (the annual rate divided by 12), and n is the total number of monthly payments.
Each payment covers the interest accrued that month first, and the remainder reduces the principal, so early payments are mostly interest and later payments are mostly principal. Total interest paid is the sum of all payments minus the original loan amount.
Sources and references
This tool provides estimates for general information only, not professional advice. See our Disclaimer. Last reviewed: July 2026.