---
title: Debt Consolidation Calculator | Roll Debts Into One | GNT Finance
description: See how much you could save by rolling credit cards, car and personal loans into one loan or your mortgage, and how the term changes the total interest paid.
url: https://gntfinance.com.au/calculators/debt-consolidation/
section: calculators
updated: 2026-09-01
author: Gorakh Timilsina, GNT Finance
---

# Debt consolidation calculator

**In short:** This calculator compares your current debts, each with its own rate and term, against one consolidated loan, and shows the change in monthly repayment and total interest. The rule of thumb: consolidating into your mortgage cuts the rate dramatically, but if you spread a $57,000 debt over 30 years you pay more interest than you do now. Keep the term short and the saving is real.

Used well, consolidation turns a 12–20% problem into a 6% one; used badly it converts a five-year debt into a thirty-year one.

## How this calculator works

### Your current debts
For each debt, the tool calculates the monthly repayment with the standard amortisation formula and multiplies it by the remaining term to find total interest. Credit cards are treated as fixed-term loans. It then reports the weighted-average interest rate across all debts.

### The consolidated loan
The combined balance is amortised at the new rate over the new term. Two scenarios are shown: repaid over the full mortgage term, and repaid over a shorter term matching your longest current debt. Establishment fees, discharge fees and any LMI triggered by lifting your home loan above 80% LVR are added.

### The comparison
The saving is the difference in total interest plus fees, alongside the change in monthly cash outlay.

## How to use the result

Look at the shorter-term scenario first; that is the honest saving because it compares like with like. The 30-year figure shows the monthly relief available if cashflow is the immediate problem, but it needs a commitment to extra repayments once you are back on your feet. If your home loan LVR would exceed 80% after consolidation, the LMI cost can wipe out the interest saving; check with the [LVR calculator](/calculators/lvr/) before applying.

## Worked example

A Roxburgh Park homeowner has a $500,000 mortgage and three other debts. For illustration, at 6.00% p.a.

| Debt | Balance | Rate | Term left | Monthly | Total interest |
| --- | --- | --- | --- | --- | --- |
| Car loan | $30,000 | 9.5% | 5 years | $630 | $7,803 |
| Credit card | $12,000 | 20% | 3 years | $446 | $4,055 |
| Personal loan | $15,000 | 12% | 4 years | $395 | $3,960 |
| **Current total** | **$57,000** | **12.4% weighted** | | **$1,471** | **$15,818** |

| Consolidation scenario | Monthly | Total interest on $57,000 |
| --- | --- | --- |
| Into mortgage over 30 years | $342 | $66,028 |
| Into mortgage, repaid over 7 years | $833 | $12,946 |
| Into mortgage, repaid over 5 years | $1,102 | $9,118 |

Stretching the debt over 30 years frees up $1,129 a month but costs $50,000 more in interest. Repaying it over five years saves $6,700 and still cuts the monthly outlay by $369. The combined $557,000 mortgage stays under 80% LVR if the home is worth at least $697,000.

## What this calculator doesn't include

- Early exit fees on existing car or personal loans.
- Credit score changes from closing accounts.
- The temptation to reuse cleared cards, the most common reason consolidation fails.
- Fixed-rate break costs if your mortgage is fixed. See [breaking a fixed-rate loan](/guides/breaking-a-fixed-rate-loan/).
- Lender limits on the number and size of debts consolidated.

## Tips to improve the outcome

- Keep paying your current combined amount so the shorter term happens automatically.
- Close or reduce the limit on cleared credit cards; lenders assess the limit, not the balance.
- If your LVR is near 80%, consolidate only the highest-rate debts.
- Consider a [personal loan](/calculators/personal-loan/) consolidation if a mortgage top-up would trigger LMI.
- If you are behind on repayments, ask your lender about [financial hardship rights](/legal/financial-hardship-rights/) first; consolidation is easier from a clean position.

## Frequently asked questions

### Is it a good idea to consolidate debt into a mortgage?

Usually yes, if you repay the consolidated amount over a similar term to the original debts, since the rate typically falls from 10–20% to a home-loan rate near 6%. It becomes a bad idea if you spread the debt over 30 years or rack up new card debt afterwards. Our [debt consolidation guide](/guides/debt-consolidation-guide/) covers the traps.

### How much can I save by consolidating debt?

On $57,000 of typical car, card and personal loan debt, repaying through the mortgage over five years saves around $6,700 in interest and reduces monthly outlay by about $370. The saving grows with the size and rate of the debts. High-rate credit cards at 20% deliver the largest gain; a low-rate car loan at 7% delivers little.

### Does debt consolidation hurt your credit score?

The application is a credit enquiry, which can dip your score briefly. Closing accounts and reducing total debt usually improves it over the following months. Missed payments during the transition do real damage, so keep paying every debt until the consolidation settles. Read [credit score and home loans](/guides/credit-score-and-home-loans/).

### Can I consolidate debt if my home loan is above 80% LVR?

Possibly, but LMI will normally apply to the whole loan, which can cost thousands. Options include consolidating only the most expensive debts, waiting for equity to grow, or using an unsecured personal loan for the balance. A broker can check which lenders allow consolidation at higher LVRs and what the premium would be.

### Will the bank let me consolidate credit cards into my home loan?

Most lenders allow it, up to a set number of debts and a maximum amount, provided the combined loan passes serviceability at the rate plus 3% buffer. The cards must be paid out at settlement and are often reduced or closed. Some lenders decline if the debts suggest ongoing overspending, so present a clear budget.

## Talk to GNT Finance

GNT Finance arranges [debt consolidation](/services/debt-consolidation/) through refinancing or top-ups and will tell you frankly whether it stacks up. Gorakh Timilsina's credit-officer background means your application is structured to pass. [Book a free consultation](/contact/) or call 0426 403 703.