TL;DR
- Whether a consolidation loan actually saves money depends on comparing its new APR against the weighted-average, or "blended," rate across all the debts being combined, not against any single card's rate in isolation. - The blended rate formula weights each debt's APR by its outstanding balance, so a large balance at a moderate rate can pull the blended figure down more than a small balance at a very high rate. - Consolidation tends to reduce total interest cost when the new APR sits meaningfully below the blended rate and the new term isn't stretched so far that added time erases the rate advantage. - Any origination fee financed into the new loan has a break-even threshold: consolidation stays cost-neutral only up to the fee amount that equals the interest saved from the lower rate. - Industry-cited ranges commonly place credit card APRs around 20-28% against personal consolidation loan APRs in the 8-16% band for borrowers with established credit, though actual offers vary by lender and credit profile.
Anyone carrying balances across several credit cards, a store card, and maybe a personal loan is really carrying several different interest rates at once. A consolidation loan replaces all of that with a single rate and a single payment, but the decision of whether that trade actually saves money comes down to a comparison most borrowers never run explicitly: the new loan's APR against the blended rate of everything it would replace.
Informational calculation reference only. All equations, tools, and outputs on this page are intended strictly for educational modeling and mathematical illustration. They do not constitute certified financial, legal, or tax advice. For specific scenarios, consult a certified public accountant (CPA) or a fiduciary financial advisor.
Why This Metric Dictates Profitability
A single card's interest rate is a misleading number to consolidate against, because most people carrying multiple debts aren't carrying equal balances at each rate. A borrower with $2,000 on a 28% APR store card and $14,000 on a 19% APR general-purpose card is not really facing a "19-28% problem." Their effective cost of debt is pulled much closer to 19% than to 28%, simply because most of the money sits on the lower-rate balance. Comparing a consolidation offer against the highest individual rate, or even a simple average of the rates, overstates the potential savings.
The blended, or weighted-average, rate corrects for this by scaling each rate by how much balance sits behind it. It answers the practical question a consolidation decision actually depends on: across every dollar currently owed, what is the effective average cost of carrying it? A new loan's APR only needs to beat that blended figure, not the highest rate in the mix, for consolidation to reduce the interest cost of the debt as a whole.
Balance and rate aren't the only variables that matter, though. Extending the repayment term is the most common way a consolidation loan quietly erases its own rate advantage. A lower monthly payment feels like an improvement, but if it comes from stretching a three-year payoff into a six-year loan, the extra years of interest accrual can offset, or even exceed, what was saved by the lower rate. Any origination fee financed into the loan balance works the same way in miniature: it's a fixed cost that has to be earned back through the rate difference before consolidation produces any net benefit at all.
Equation and Data Inputs
The blended rate across every debt being consolidated is each balance's APR weighted by its share of the total balance:
r_{\text{blended}} = \frac{\sum_{i=1}^{n} B_i \times r_i}{\sum_{i=1}^{n} B_i}
where $B_i$ is the outstanding balance on debt $i$ and $r_i$ is that debt's APR. Consider four balances: $6,000 at 24% APR, $9,000 at 21% APR, $3,000 at 27% APR, and $2,000 at 19% APR, totaling $20,000. The blended rate works out to approximately 22.6% — closer to the two largest balances' rates than to a simple, unweighted average of the four APRs, which would land near 22.75% purely by coincidence in this example and can diverge substantially when balances are less evenly sized.
The new consolidated loan's monthly payment follows the standard installment-loan amortization formula, applied to the combined balance plus any financed fee:
M = \frac{(B + F) \times r}{1 - (1 + r)^{-n}}
where $B$ is the total balance being consolidated, $F$ is an origination fee financed into the loan, $r$ is the new loan's monthly rate (New APR $\div$ 12), and $n$ is the loan term in months.
The break-even relationship ties the two together. Consolidation reduces total cost only when the interest saved by moving from the blended rate to the new loan's rate exceeds any financed fee:
F_{\text{break-even}} = \text{Total Interest}_{\text{current path}} - \text{Total Interest}_{\text{consolidated}}
A financed fee below $F_{\text{break-even}}$ leaves net savings; a fee above it means the fee has consumed more than the rate advantage was worth. On the $20,000 example above, moving from a 22.6% blended rate to a 48-month loan at 13.5% APR with a $600 financed fee produces a lower monthly payment and a materially lower total interest cost in most amortization scenarios, though the exact dollar figure depends on how quickly the current balances would otherwise be paid down.
Benchmark Ranges
The size of the gap between the blended rate and the new loan's APR is the single biggest driver of how much a consolidation actually saves, independent of the specific dollar amounts involved.
| Gap: blended rate minus new loan APR | Typical outcome |
|---|---|
| New APR at or above the blended rate | Consolidation rarely reduces total interest cost; a longer term may still lower the monthly payment |
| 2-5 percentage points lower | Modest savings that are sensitive to fees and any term extension |
| 5-10 percentage points lower | Meaningful savings in most equal-or-shorter-term scenarios |
| 10+ percentage points lower | Substantial savings typical of the gap often cited between revolving card APRs (roughly 20-28%) and personal consolidation loan APRs (roughly 8-16%) for well-qualified borrowers |
Disclaimer: While we strive for absolute mathematical precision, actual real-world financial outcomes may vary based on institutional fees, localized tax brackets, changes in federal legislation, or fluctuating market indexes.