How does this debt consolidation calculator work?

It adds a simple P&I estimate for your home loan to the minimum payments on other debts, then compares that with one P&I repayment if those balances were added to the mortgage at a rate and term you enter. Other-debt interest is simulated from the minimums you type. Educational only. Not a lender quote.

Why can total interest go up even when the monthly payment drops?

Because stretching short consumer debt across a long mortgage term can mean more years of interest. That is the term trap. Try a shorter consolidated term, or ask a licensed adviser about a separate shorter split for the old debt.

Does this include break fees or refinance costs?

No. Break fees, legal costs, valuation, discharge fees, and cashback clawback are outside this model. If you leave a fixed rate early or switch lenders, get those quotes and net them separately.

Can I use this instead of talking to a broker?

No. Use it to frame questions. Approval, LVR, servicing, and structure need a real assessment. Online Home Loans is a referral service. We do not give mortgage advice or arrange lending.

Is consolidating into the mortgage always a good idea?

No. It can help cashflow when criteria allow, and it can hurt if the term stretches, habits stay the same, or fees wipe the benefit. A licensed adviser should show both the monthly picture and the total cost picture.

Calculator

Debt consolidation calculator

Thinking about rolling credit cards or personal loans into your mortgage? Plug in your home loan, other debts, and an assumed rate and term for a plain-English monthly and interest sketch. Online Home Loans is referral only. We do not give mortgage advice. Outputs are estimates, not quotes.

Debt consolidation estimate

Rough monthly outs today (home loan P&I plus other minimums) versus one mortgage repayment if those balances were rolled in at a rate and term you choose. Total interest is a teaching estimate. Not a quote.

Home loan balance (NZD)Approximate principal still owing on the mortgage.Home loan rate (% p.a.)Remaining home loan term (years)Used for a simple P&I estimate of today's mortgage repayment and remaining interest.

Other debts (credit cards, personal loans, etc.)

Add each facility with balance, rate, and the minimum you pay now. Leave unused rows at zero or remove them.

Debt 1

LabelBalance (NZD)Rate (% p.a.)Min payment (NZD / mo)

Debt 2

LabelBalance (NZD)Rate (% p.a.)Min payment (NZD / mo)

If rolled into the mortgage

Enter the rate and term you want to model for the combined balance. Banks may structure a shorter split for the consolidated portion. This tool uses one blended term for simplicity.

Assumed mortgage rate (% p.a.)Assumed term (years)A longer term can drop the monthly figure while raising total interest. Try a shorter term as a second scenario.

Results (estimates only)

Other debts to roll in: $20,000. Combined principal modelled: $470,000.

Monthly cost today (est.): $3,241 /mo; Home P&I $2,761 + other mins $480
Monthly if consolidated (est.): $2,745 /mo; Single P&I on combined balance at 4.99% over 25 years
Monthly cashflow change: $496 lower /mo

Total interest today path (rough): $387,457; Home remaining interest $378,212 + other debts $9,244
Total interest if consolidated (rough): $353,451; Over the full 25-year term on the combined balance

Rough interest difference: $34,006 less if consolidated on these assumptions. Different terms make this an apples-to-oranges teaching figure, not a bank quote.

Plain-English take

On these rough figures both monthly cashflow and total interest look better. Fees, break costs, LVR, servicing, and whether old credit lines stay open can still change the real outcome. Talk to a licensed broker before you plan around it.

How the maths works

Today's home repayment ≈ standard P&I on the home balance at the home rate and remaining term.
Today's other outs ≈ sum of the minimum payments you entered.
Consolidated repayment ≈ P&I on (home + other balances) at the assumed rate and term.
Home interest remaining ≈ (home P&I × months) − home balance. Other-debt interest is simulated month by month at the stated rate until the minimum clears the balance (or flagged if it never does).
Consolidated interest ≈ (consolidated P&I × months) − combined principal.

Ignores offset accounts, split loans, fees, promotional card rates, and lender policy. Real approvals are usually tighter than a spreadsheet sketch.

When Kiwis usually run these numbers

People often compare cashflow before a top-up or a full refinance that folds higher-rate debt into the home loan. Equity room matters too. Pair this with the cash out equity calculator and the debt consolidation overview for the bigger picture.

What this tool does not do

It does not check servicing, DTI, credit, or LVR.
It does not include break fees, legal costs, or clawback.
It does not model separate shorter splits for consolidated debt.
It does not recommend consolidating, refinancing, or staying put.

Use it to frame the conversation, then talk to a licensed broker about your actual numbers.

Common questions

How does this debt consolidation calculator work?: It adds a simple P&I estimate for your home loan to the minimum payments on other debts, then compares that with one P&I repayment if those balances were added to the mortgage at a rate and term you enter. Other-debt interest is simulated from the minimums you type. Educational only. Not a lender quote.
Why can total interest go up even when the monthly payment drops?: Because stretching short consumer debt across a long mortgage term can mean more years of interest. That is the term trap. Try a shorter consolidated term, or ask a licensed adviser about a separate shorter split for the old debt.
Does this include break fees or refinance costs?: No. Break fees, legal costs, valuation, discharge fees, and cashback clawback are outside this model. If you leave a fixed rate early or switch lenders, get those quotes and net them separately.
Can I use this instead of talking to a broker?: No. Use it to frame questions. Approval, LVR, servicing, and structure need a real assessment. Online Home Loans is a referral service. We do not give mortgage advice or arrange lending.
Is consolidating into the mortgage always a good idea?: No. It can help cashflow when criteria allow, and it can hurt if the term stretches, habits stay the same, or fees wipe the benefit. A licensed adviser should show both the monthly picture and the total cost picture.