What steps does the calculator follow?
First it adds up your balances to get the total that becomes the new loan's principal. Then it multiplies each loan's balance by its rate, adds those products and divides by the total balance. That is the weighted average rate, which gives larger loans more say than a simple average would.
Next it rounds the weighted average up to the next multiple of 0.125%. A 5.10% average becomes 5.125%; an average that already sits on an eighth stays put. This rounded figure is the consolidated rate.
Finally, it amortizes the total balance at the consolidated rate over the term you enter to get the new monthly payment and total interest. It also reports the longest federal term allowed for your balance under the tiered schedule the calculator uses.
Weighted rate = Σ(balance × rate) ÷ Σ(balance) Consolidated rate = ceiling(Weighted rate ÷ 0.125%) × 0.125% M = T × r × (1 + r)^n ÷ ((1 + r)^n − 1)
- T
- total of all balances
- r
- consolidated rate ÷ 12
- n
- consolidation term in months
- M
- new monthly payment
Example: consolidating four loans totaling $41,500
Scenario: A borrower holds four federal loans: $9,500 at 4.99%, $14,200 at 5.50%, $6,800 at 6.54% and $11,000 at 7.05% (illustrative rates).
- Total balance$9,500 + $14,200 + $6,800 + $11,000 = $41,500.00
- Balance × rate$474.05 + $781.00 + $444.72 + $775.50 = $2,475.27
- Weighted average rate$2,475.27 ÷ $41,500.00 = 5.965%
- Round up to the next 1/8%5.965% rounds up to 6.000%
- New payment over 10 years$41,500.00 at 6.000% ÷ 12 over 120 months = $460.74; total interest $13,788.80
- Maximum federal term$41,500 falls in the $25,000–$49,999 tier, so the longest term shown is 15 years
The consolidated loan would carry 6.000% and cost $460.74 a month over 10 years, or $350.20 over 15 years with $21,536.00 in interest.
Your servicer's figures include any unpaid interest on the old loans, which can raise the starting balance.
When is it worth running a consolidation estimate?
Simplifying several federal loans
If multiple servicers or due dates are causing missed payments, consolidation can help. The calculator shows what the single payment would be.
Checking a servicer's quoted rate
Enter your loans to confirm the weighted average and rounding match the rate on your consolidation paperwork.
Choosing a consolidation term
Compare the payment and interest at 10 years with the maximum term for your balance to see the cost of the lower payment.
Comparing with private refinancing
The consolidated rate here is the federal baseline. A private refinance offer would need a meaningfully lower rate to justify losing federal protections.
What do borrowers get wrong about consolidation?
Expecting a lower rate
Federal consolidation averages your rates and rounds up. Any payment drop comes from the term, not the rate.
Using a simple average
Averaging rates without weighting by balance gives the wrong answer whenever balances differ. Larger loans pull the average toward their rate.
Including private loans
Private student loans cannot go into a federal Direct Consolidation Loan. Only federal loans qualify.
Stretching to the maximum term by default
The longest term can add thousands in interest. Pick the shortest term your budget can comfortably carry.
Forgetting about borrower benefits
Consolidation can affect things like progress toward forgiveness or interest benefits on certain loans. Check with your servicer before applying.
Does consolidating actually change what you pay?
Keeping the same 10-year horizon, consolidation changes very little. Paying the four loans separately over 10 years costs $460.18 a month and $13,721.60 in interest. The 10-year consolidated loan costs $460.74 a month and $13,788.80 in interest; the slightly higher cost comes entirely from rounding the rate up to the next eighth of a percent.
Stretching to 15 years is where the real change happens: the payment drops to $350.20, but interest climbs to $21,536.00. Consolidation is mostly a tool for simplicity and payment flexibility, not for saving money.
| Approach | Monthly payment | Total interest |
|---|---|---|
| Four separate loans, 10 years each | $460.18 | $13,721.60 |
| Consolidated at 6.000%, 10 years | $460.74 | $13,788.80 |
| Consolidated at 6.000%, 15 years | $350.20 | $21,536.00 |
Terms used on this page
- Debt Consolidation
- Debt consolidation means combining several debts into one new loan or account, ideally with a lower interest rate and a single monthly payment. Common tools include personal loans, balance transfer cards and home equity loans. It saves money only if the new rate and fees are lower and you avoid running the old balances back up.
- Interest Rate
- An interest rate is the price of money, stated as a percentage of the balance per year. Borrowers pay it to lenders, and savers earn it from banks. The rate alone does not include fees or compounding, so it can understate the true yearly cost of a loan or overstate a simple comparison of savings accounts.
- Capitalized Interest
- Capitalized interest is unpaid interest that gets added to a loan's principal balance. After capitalization, you pay interest on that interest, which raises both your payment and total cost. It commonly happens with student loans after periods when payments are paused, such as school, a grace period or certain forbearance and deferment periods.
- Loan Term
- The loan term is the length of time you have to repay a loan, usually stated in months for consumer loans. A longer term lowers the monthly payment but increases the total interest you pay, because the balance stays outstanding longer. A shorter term costs more each month and less overall.
- Refinancing
- Refinancing replaces an existing loan with a new one, usually to get a lower interest rate, a different term or a lower payment. The new lender pays off the old loan, and you repay the new one. It saves money when the rate drop outweighs any fees, but stretching the term can raise total interest.
Student Loan Consolidation Calculator: common questions
Does consolidating student loans lower the interest rate?
Not for federal consolidation. The new rate is the weighted average of your current rates, rounded up to the nearest one-eighth of a percent, so it is the same or slightly higher. A private refinance can lower the rate if your credit and income qualify, but it replaces federal loans with a private loan.
How do I calculate a weighted average interest rate?
Multiply each loan's balance by its rate, add the results, and divide by the total balance. For example, $12,000 at 4.5% and $8,000 at 6% give ($540 + $480) ÷ $20,000 = 5.1%. A simple average would say 5.25%, which overweights the smaller loan. The consolidation calculator does this automatically for up to four loans.
Why is the consolidated rate rounded up to 1/8 percent?
It is the rule federal Direct Consolidation Loans use: the weighted average is rounded up to the next one-eighth of a percentage point. The effect is small, at most 0.125 percentage points, but it means consolidation never lowers your average federal rate. The rate then stays fixed for the life of the loan.
What is the longest term for a federal consolidation loan?
It depends on the total balance. The tiered schedule this calculator uses for consolidations made on or after July 1, 2026, allows 10 years under $25,000, 15 under $50,000, 20 under $100,000 and 25 at $100,000 or more. Older consolidations used a different schedule, so confirm the current rules with Federal Student Aid.
Will consolidation lower my monthly payment?
Only if you choose a longer term than you have now, or if an income-driven plan applies afterward. At the same term, the payment is about the same because the rate is about the same. The lower payment from a longer term comes with more total interest, which the calculator shows.
Can I consolidate private and federal student loans together?
Not into a federal Direct Consolidation Loan, which accepts only eligible federal loans. Some private lenders will refinance both federal and private loans into one private loan, but federal loans moved that way lose access to federal repayment plans, deferment options and forgiveness programs. Weigh those protections carefully before moving federal loans to a private lender.
Does unpaid interest get added when I consolidate?
Generally, yes. Outstanding interest on the loans being consolidated is included in the new principal, so it starts earning interest. If you can, paying accrued interest before consolidating keeps the new balance smaller. Use your current payoff amounts, not original balances, when you enter loans here. Ask your servicer for payoff amounts dated close to your application.
Should I consolidate federal student loans?
It depends on your goals. Consolidation can simplify billing and may be needed for some loans to qualify for certain repayment or forgiveness programs. It does not save interest and can cost more if you lengthen the term. Compare the numbers here with your current payments, and ask your servicer how it affects any benefits.
Can I still pay extra after consolidating?
Yes. Federal student loans have no prepayment penalty, so you can choose a longer consolidation term for flexibility and pay extra when cash allows. The risk is that extra payments slip, leaving you on the costlier schedule. Ask the servicer to apply extra amounts to principal. Directing extra to principal early in the term saves the most interest.
Sources
- Direct Consolidation Loans — Federal Student Aid (U.S. Department of Education). Accessed October 17, 2026.
- Student loan repayment plans — Federal Student Aid (U.S. Department of Education). Accessed October 17, 2026.
- Federal student loan interest rates — Federal Student Aid (U.S. Department of Education). Accessed October 17, 2026.
- Student loans — Consumer Financial Protection Bureau. Accessed October 17, 2026.
We cite primary sources: regulators, central-bank data and federal agencies. Worked examples on this page are our own calculations, last checked October 17, 2026. See our methodology.