Debt Consolidation Savings Calculator Formula

Understand the math behind the debt consolidation savings calculator. Each variable explained with a worked example.

Use the Debt Consolidation Savings Calculator

Formulas Used

New Monthly Payment

new_payment = new_monthly_rate > 0 ? current_balance * new_monthly_rate * pow(1 + new_monthly_rate, num_payments) / (pow(1 + new_monthly_rate, num_payments) - 1) : current_balance / num_payments

Total Interest (Consolidation)

new_total_interest = new_monthly_rate > 0 ? (current_balance * new_monthly_rate * pow(1 + new_monthly_rate, num_payments) / (pow(1 + new_monthly_rate, num_payments) - 1)) * num_payments - current_balance : 0

Total Interest (Current Path)

old_total_interest = old_monthly_rate > 0 ? (current_balance * old_monthly_rate * pow(1 + old_monthly_rate, num_payments) / (pow(1 + old_monthly_rate, num_payments) - 1)) * num_payments - current_balance : 0

Interest Savings

savings = (old_monthly_rate > 0 ? (current_balance * old_monthly_rate * pow(1 + old_monthly_rate, num_payments) / (pow(1 + old_monthly_rate, num_payments) - 1)) * num_payments - current_balance : 0) - (new_monthly_rate > 0 ? (current_balance * new_monthly_rate * pow(1 + new_monthly_rate, num_payments) / (pow(1 + new_monthly_rate, num_payments) - 1)) * num_payments - current_balance : 0)

Variables

VariableDescriptionDefault
current_balanceTotal Current Debt(USD)25000
current_rateCurrent Weighted Avg Rate(%)22
new_rateConsolidation Loan Rate(%)10
loan_termConsolidation Loan Term(years)5
old_monthly_rateDerived value= current_rate / 12 / 100calculated
new_monthly_rateDerived value= new_rate / 12 / 100calculated
num_paymentsDerived value= loan_term * 12calculated

How It Works

Debt Consolidation

Consolidation replaces multiple high-rate debts with a single lower-rate loan.

When It Makes Sense

  • Your new rate is significantly lower than your current average rate
  • You will NOT run up new debt on the freed credit cards
  • The total cost (including fees) is less than your current path

    • Formula

    Both scenarios use the standard loan payment formula:

    M = P x r x (1+r)^n / [(1+r)^n - 1]

    The difference in total interest between old and new rates is your savings.

    Worked Example

    $25,000 at 22% average vs consolidation at 10% for 5 years.

    current_balance = 25000current_rate = 22new_rate = 10loan_term = 5
    1. 01New payment = $25,000 at 10% for 60 months = $531
    2. 02New total interest = $531 x 60 - $25,000 = $6,874
    3. 03Old total interest at 22% = $707 x 60 - $25,000 = $17,418
    4. 04Interest savings = $17,418 - $6,874 = $10,544

    Frequently Asked Questions

    Is debt consolidation a good idea?

    It can save thousands in interest IF you get a meaningfully lower rate and do not accumulate new debt. Be wary of extending the repayment term so long that you end up paying more total interest despite the lower rate.

    Will consolidation hurt my credit score?

    Initially, a hard inquiry and new account may slightly lower your score. Over time, consolidation often helps by reducing credit utilization and establishing consistent payment history.

    What about balance transfer vs personal loan?

    Balance transfers offer 0% intro rates but typically for 12-21 months with a 3-5% fee. Personal loans have fixed rates and terms. Choose based on how quickly you can pay off the balance.

    Ready to run the numbers?

    Open Debt Consolidation Savings Calculator