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 |