Student Loan to Income Calculator
Calculate student loan debt-to-income from balance and starting salary.
Returns monthly payment and affordability rating under the 10% income guideline.
Student loan repayment as a percentage of income is one of the most important metrics for evaluating whether a degree is financially sustainable. The general rule from financial planners is that monthly loan payments should not exceed 8–10% of gross monthly income.
The affordability formula:
Payment-to-Income Ratio (%) = Monthly Loan Payment ÷ Gross Monthly Income × 100
Gross Monthly Income = Annual Salary ÷ 12
Federal income-driven repayment (IDR) plans base payments on income:
IDR Monthly Payment = (Discretionary Income × Plan Rate) ÷ 12
Discretionary Income = Adjusted Gross Income − (150% × Federal Poverty Line)
IDR plan rates:
| Plan | Payment Rate | Forgiveness |
|---|---|---|
| SAVE (new) | 5–10% | 20–25 years |
| PAYE | 10% | 20 years |
| IBR (new borrowers) | 10% | 20 years |
| IBR (older borrowers) | 15% | 25 years |
| ICR | 20% | 25 years |
Worked example: A social worker earns $48,000/year ($4,000/month gross). Student loan balance: $55,000 at 6.5%, 10-year standard plan.
- Standard payment: $622/month
- Payment ratio: $622 ÷ $4,000 = 15.6%: above the recommended 10% threshold
- Under SAVE plan (10% discretionary income): assuming $20,000 poverty adjustment:
- Discretionary income: $48,000 − $24,420 = $23,580
- Annual payment: $23,580 × 10% = $2,358
- Monthly payment: $197/month = 4.9% of income
Debt-to-income benchmarks:
| Ratio | Assessment |
|---|---|
| Under 8% | Manageable, minimal financial strain |
| 8–12% | Moderate, monitor other debt levels |
| 12–20% | High, consider IDR or refinancing |
| Over 20% | Severe, financial counseling recommended |
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This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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