How to Calculate Your Loan Repayment
Understanding exactly what your loan will cost each month — and in total — is one of the most important calculations in personal finance. Every fixed-rate loan uses the same amortization formula. The monthly payment is calculated so that each payment covers that month's interest while also reducing the principal, and after the final payment the balance reaches exactly zero.
P = Loan Principal | r = Monthly Rate (APR ÷ 12) | n = Total Months
Example: $20,000 at 6% over 5 years → r = 0.005, n = 60
M = 20,000 × [0.005 × (1.005)^60] ÷ [(1.005)^60 − 1] = $386.66/month
The key insight in amortization is that early payments are mostly interest while later payments are mostly principal. On a 30-year mortgage, more than 80% of your first payment goes to interest. This is why making extra payments — especially early in the loan — has such a dramatic effect on total interest paid and loan duration.
How Extra Payments Save You Thousands
Every extra dollar you pay reduces the principal balance, which reduces the interest that accrues the following month. This creates a compounding benefit that accelerates over time.
Standard payment: $1,896/month → Total interest: $382,633
With extra $200/month → Paid off 5 years 9 months early
Total interest: $297,448 → Interest saved: $85,185
Before making extra payments, check your loan agreement for prepayment penalties. Most personal loans and modern mortgages have no penalty, but some older or specialist products do. Use the Extra Payment field above to calculate your exact savings.
Loan Amount vs Monthly Payment — Full Comparison Table
The table below shows monthly payments for the most common loan amounts at 7% APR across different terms. All figures are for fixed-rate fully amortizing loans.
| Loan Amount | 3 Years | 5 Years | 7 Years | 10 Years | Interest (5yr) |
|---|---|---|---|---|---|
| $5,000 | $154/mo | $99/mo | $75/mo | $58/mo | $940 |
| $10,000 | $309/mo | $198/mo | $151/mo | $116/mo | $1,881 |
| $15,000 | $463/mo | $297/mo | $226/mo | $174/mo | $2,821 |
| $20,000 | $618/mo | $396/mo | $302/mo | $232/mo | $3,761 |
| $25,000 | $772/mo | $495/mo | $377/mo | $290/mo | $4,702 |
| $30,000 | $926/mo | $594/mo | $453/mo | $348/mo | $5,642 |
| $40,000 | $1,235/mo | $792/mo | $604/mo | $464/mo | $7,523 |
| $50,000 | $1,544/mo | $990/mo | $755/mo | $581/mo | $9,404 |
| $75,000 | $2,316/mo | $1,485/mo | $1,132/mo | $871/mo | $14,105 |
| $100,000 | $3,088/mo | $1,980/mo | $1,509/mo | $1,161/mo | $18,807 |
| $200,000 | $6,175/mo | $3,960/mo | $3,019/mo | $2,322/mo | $37,614 |
| $300,000 | $9,263/mo | $5,940/mo | $4,528/mo | $3,483/mo | $56,422 |
| $500,000 | $15,439/mo | $9,901/mo | $7,546/mo | $5,805/mo | $94,036 |
Everything You Need to Know About Loan Repayment
📊 Understanding Amortization
Amortization spreads your loan repayment into equal monthly instalments. Each payment covers that month's interest first, with the remainder reducing your principal balance. In early months of a 30-year mortgage, over 90% of your payment can be interest. Use the amortization schedule above to see exactly how your balance decreases each month.
🏠 Mortgage Loans: What You Need to Know
A mortgage is typically the largest loan most people take. In the US, the most common terms are 15 and 30 years. A 30-year mortgage has lower monthly payments but far more total interest. A 15-year mortgage typically has a lower rate and less than half the total interest cost. In 2026, average 30-year fixed rates are around 6.5–7%. Always factor in property taxes, homeowner's insurance, and possibly PMI when budgeting.
🚗 Car Loan Repayment Tips
Auto loans typically run 24–84 months. Longer terms reduce monthly payments but increase total interest and create a risk of being underwater — owing more than the car is worth. The sweet spot is 48–60 months on a new car and 36–48 months on used. In 2026, new car loan rates average 6.5% for good credit; used car rates are typically 2–4% higher.
💳 Personal Loan vs Credit Card
Personal loans offer rates of 8–20% APR with fixed terms — far lower than the average credit card rate of 20–29% APR. If you carry a credit card balance, consolidating with a personal loan can save significant money. Transferring a $10,000 balance at 24% to a personal loan at 12% over 3 years saves approximately $2,200 in interest. The fixed end date is the key advantage — credit card debt can last indefinitely.
🎓 Student Loan Repayment Strategies
Federal student loans in the US (2026) carry rates of 5.5–8.05% depending on type. Key strategies: income-driven repayment plans cap payments at 5–10% of discretionary income; Public Service Loan Forgiveness (PSLF) forgives balances after 10 years of qualifying employment; and refinancing to private lenders can lower rates but forfeits federal protections. Always exhaust federal options first.
💡 Interest Rate vs APR: Key Difference
The interest rate is the base annual cost of borrowing — it does not include fees. The APR includes the interest rate plus all lender fees, origination fees, mortgage points, and broker costs, expressed as a yearly percentage. APR is always ≥ the interest rate and is the best number to use when comparing loan offers, as it reflects the true total cost of borrowing.
Loan Repayment and Your Finances: 2026 Context
With US interest rates remaining elevated in 2026 following the Federal Reserve's rate cycle, understanding your loan costs has never been more important. A useful rule of thumb: your total monthly debt payments should not exceed 36% of your gross monthly income. Your housing costs alone should ideally stay below 28%. Use our Salary to Hourly Calculator to determine your gross monthly income if needed.
Debt-to-Income Ratio (DTI) — Why It Matters
Your DTI ratio is the percentage of gross monthly income going toward debt payments. Lenders use this as a primary approval factor. A DTI below 36% is healthy; most conventional mortgage lenders cap at 43–45%. Reducing your DTI by paying off existing debt before applying for a new loan can save you thousands in interest over the term.
To calculate DTI: add all monthly minimum debt payments and divide by gross monthly income. If you earn $5,000/month and have $1,500 in debt payments, your DTI is 30% — within healthy range for most lenders.
Frequently Asked Questions
Related Financial Calculators
Use these free tools alongside the Loan Repayment Calculator for a complete picture of your finances:
- Salary to Hourly Calculator — understand how many hours of work your loan repayment costs you
- Monthly Budget Planner — fit your loan repayment into your monthly budget
- Debt Payoff Calculator — avalanche vs snowball method comparison
- Savings Goal Calculator — save for a deposit to reduce your loan amount
- Net Worth Calculator — track your assets vs liabilities including loan balances