📖 Overview
Use this tool to see the full financing cost beyond just the monthly payment.
🧪 Example Scenarios
Use these default and higher-pressure example inputs to explore how sensitive this calculator is before using your real numbers.
| Input | Base Case | Higher Pressure Case |
|---|---|---|
| Loan Amount ($) | 30,000 | 34,500 |
| Annual Interest Rate (%) | 7.5 | 9 |
⚙️ How It Works
This formula estimates total borrowing cost by subtracting principal from total payments across a 60-month term.
The Formula
Total Interest = (Monthly Payment × 60) − Principal
| Monthly Payment | Fixed payment from amortization formula |
| 60 | Number of months in a 5-year term |
| Principal | Original loan amount |
💡Total interest is the true cost of borrowing. A loan with a lower monthly payment but higher rate can end up costing thousands more overall.
Quick Reference
| Loan | 3% | 6% | 9% | 12% |
|---|---|---|---|---|
| $10,000 | $779 | $1,600 | $2,457 | $3,347 |
| $20,000 | $1,558 | $3,200 | $4,913 | $6,693 |
| $30,000 | $2,337 | $4,800 | $7,370 | $10,040 |
When To Use This
- Use this tool when you need a fast decision during active planning or execution.
- Use this before committing money, time, or tradeoffs that are hard to reverse.
- Use this to compare options using the same assumptions across scenarios.
Edge Cases To Watch
- Results can be misleading if key inputs are missing, stale, or unrealistic.
- Very small or very large values may amplify rounding effects and interpretation risk.
- If assumptions change mid-decision, recalculate before acting.
Practical Tips
💡 Use total interest to compare whether borrowing is worth the purchase.
💡 A small APR drop can reduce total interest significantly.
💡 Re-check this estimate if your term length changes.
Frequently Asked Questions
❓ Why is total interest important?
It shows the real cost of financing beyond the headline monthly payment.
❓ Can I lower this number?
Yes, with lower rates, shorter terms, or extra principal payments.