Number Student Loan Calculator
Student debt rarely comes as one loan — it arrives as a stack of them, each with its own rate. Add up to five, set one repayment term, and see the combined payment, the total interest, and what an extra payment does across the whole stack.
Each loan’s minimum is the standard amortizing payment for the term you set. Extra money is aimed at the highest-rate loan first (the avalanche order), which is the cheapest way through the stack.
How it works
Every loan gets its own standard payment — balance × monthly rate ÷ (1 − (1 + monthly rate)−term) — and the minimums simply add up. The simulator then walks the stack month by month: minimums everywhere, interest accruing on each balance, and any extra payment aimed at the highest APR first. When a loan dies, its minimum rolls into the extra for the next one, which is why the payoff speeds up toward the end.
Formula & worked example
Formula: Each loan gets the standard amortizing payment for the term — balance × monthly rate ÷ (1 − (1 + monthly rate)−term) — and the minimums add up. Extra money is aimed at the highest APR first (avalanche order); when a loan is cleared, its minimum rolls into the attack on the next.
Worked example: Two loans on a 10-year term: $5,000 at 5% costs $53.03 a month and $7,000 at 6.5% costs $79.48 — a combined $132.52, with $3,901.96 of interest over 120 months. Add $100 a month extra aimed at the 6.5% loan and everything is gone in 60 months, with $1,784.55 of interest: $2,117.41 saved.
When to use this
- You graduated with several loans at different rates and have never seen them as one combined payment.
- A servicer shows each loan separately and you want the single monthly number your budget has to carry.
- You have extra money each month and want it aimed where it mathematically does the most damage.
- You are weighing the standard 10-year plan against stretching the term, and want the interest price of stretching in dollars.
How to use it, step by step
- Add one row per loan (up to five) with its current balance and APR.
- Set one repayment term in months that will apply across the stack.
- Read the combined minimum payment and the per-loan minimums it is built from.
- Add an extra monthly payment — it is aimed at the highest-rate loan first, and freed minimums roll into the attack as loans die.
- Compare the months and total interest with and without the extra before deciding.
What the inputs mean
| Input | What it is | Typical values |
|---|---|---|
| Balance (per loan) | What each loan currently owes, one row per loan | A few thousand per semester loan; totals often $20k–$40k |
| APR (per loan) | Each loan's own rate — they rarely match | Federal undergraduate loans recently around 5–7%; private loans vary widely |
| Repayment term (months) | One shared term applied to every loan | 120 months is the federal standard plan |
| Extra payment per month | Extra cash aimed at the highest APR first | $50–$200 is where payoff dates start moving years |
Another worked example
Three loans on a 10-year (120-month) term: $8,000 at 4.5% (minimum $82.91), $12,000 at 5.8% (minimum $132.02) and $6,000 at 7% (minimum $69.67) combine to $284.60 a month and $8,151.81 of interest if you pay only the minimums. Add $200 a month extra, aimed at the 7% loan first, and the whole stack is gone in 62 months with $3,797.87 of interest — $4,353.94 saved and nearly five years of payments avoided.
Frequently asked questions
How do I find the payment on several student loans?
Work out each loan’s standard payment for your term, then add them. Two loans — $5,000 at 5% and $7,000 at 6.5% — on a 10-year term cost $53.03 + $79.48 = $132.52 a month and $3,901.96 of interest in total. The calculator above does the adding for up to five loans.
Which student loan should extra money hit first?
Mathematically, the highest interest rate — every dollar there removes the most future interest. On the example stack, $100 a month extra aimed at the 6.5% loan clears everything in 60 months instead of 120 and saves $2,117.41 of interest.
Is a 10-year term always right?
It is the federal standard plan, but not a law. A shorter term raises the payment and cuts interest hard; a longer term does the opposite and can cost more than the original degree expenses you financed. Model two or three terms above and compare the total interest line, not just the monthly one.
Should I pay extra on federal student loans?
Only after weighing what you give up: income-driven repayment, Public Service Loan Forgiveness and hardship deferment are worth real money. If none of those plausibly apply to you, extra payments are a guaranteed return equal to the loan’s APR.
🧮 More than student debt?
The Debt Snowball Calculator lines up six debts of any kind and races the snowball against the avalanche.
Can I put federal and private loans in the same run?
Yes — the arithmetic does not care who holds the loan, so enter every balance and APR you owe. What the math cannot weigh is the difference in protections: federal loans carry income-driven plans, deferment and forgiveness options that private loans do not, which is why many borrowers aim extra payments at private loans even when a federal loan's rate is a little higher.
What if my loans do not all have the same time left?
This calculator applies one shared term to the whole stack, which is the right picture if you are setting a single payoff plan from today. If one loan is years older than the others, run that loan on its own in the Loan Calculator with its real remaining term, then add the two results — otherwise the shared-term assumption will flatter the older loan's payment.