Loan Repayment Calculator

A fixed repayment is the loan × r ÷ (1 − (1 + r) to the power of −n), where r is the yearly interest rate divided by the number of repayments a year and n is the number of repayments over the term. At 0% it is simply the loan divided by n. Each repayment pays that period’s interest on the balance first and the rest reduces what you owe, so $50,000 at 8.5% over 5 years is $1,025.83 a month. A balloon left owing at the end is taken off first: the repayment covers the loan less the balloon’s value today.

Over 30 years, $2,997.75 a month at 6% and $3,160.34 at 6.5%, worked the textbook way with the yearly rate divided by 12 each month. At 6% that adds up to $579,193 of interest over the full term. At 6.2%, the Reserve Bank’s average variable rate on new owner-occupier loans in September 2026, it is $3,062.34 a month. Paying fortnightly or weekly, or keeping savings in an offset account, brings the interest down; the calculator shows by how much.

At the same rate and term, more frequent repayments cost slightly less, because the balance falls sooner: on $50,000 at 8.5% over 5 years the interest is $11,549.54 monthly, $11,455.72 fortnightly and $11,415.89 weekly. The bigger saving comes from paying half the monthly repayment every fortnight: 26 half-repayments a year add up to 13 monthly repayments, which cuts the interest to $10,304.03 and finishes about 6 months sooner. Check how your lender sets its fortnightly amount before counting on it.

Every extra dollar comes straight off the balance, so each later repayment carries less interest and the loan ends early. Adding $100 a month to $50,000 at 8.5% over 5 years saves $1,299.88 of interest and finishes 6 months sooner. A one-off lump sum works the same way: $20,000 paid in mid-2028 on a $600,000 home loan at 6.2% saves $88,317 and ends 2 years 5 months sooner. Before paying extra, check that the loan allows it: a fixed rate loan may charge a fee if you repay it early.

The balance in an offset account is taken off the loan before interest is worked out, so with $50,000 in the offset of a $600,000 loan you are charged interest on $550,000. Moneysmart notes that most home loans calculate interest daily, so the money counts every day it stays there. The repayment does not change, so more of it comes off the loan: on $600,000 at 6.2% over 30 years, keeping $50,000 in the offset saves $214,917 of interest and finishes 4 years 10 months sooner. Some loans charge for an offset through a higher rate or fees, so weigh those against the saving.

The loan becomes principal and interest, and the repayment rises because you start repaying the amount borrowed over the years left. On $500,000 at 6.4% over 30 years with five years interest-only, the repayment is about $2,668 a month at first and $3,346.04 afterwards, against $3,128.64 for principal and interest from the start. Because nothing comes off the balance for five years, the interest-only loan costs $37,587 more interest over its life. Moneysmart suggests making sure you can afford the higher repayment before you choose one.

A balloon (or residual) is a lump sum left owing at the end of the loan and paid in one go, so the regular repayments only pay off the rest. On $45,000 at 8.5% over five years, a 30% balloon of $13,500 brings the repayment down from $923.24 to $741.90 a month, but the balance stays higher for longer, so it costs $2,619 more interest. Moneysmart suggests being confident you can pay the lump sum when it falls due.

On a $600,000 home loan over 30 years at 6.2%, a rise of one percentage point to 7.2% lifts the monthly repayment from $3,676.10 to $4,074.26, about $398 a month more, and 8.2% makes it $4,488.30 and 9.2% makes it $4,916.33. The calculator lists the same three rises for any loan you enter.

Moneysmart notes that interest on most home loans is calculated daily: the balance × the yearly rate ÷ 365 × the days since the last repayment, so a 31-day month carries a little more interest than a 28-day one. Textbook figures divide the yearly rate by 12 instead. The repayments land close together: on $600,000 at 6.2% over 30 years, $3,676.10 a month worked daily against $3,674.81 worked monthly. The calculator does either: choose “Interest worked out: Daily” under More options.

Generally yes, for the interest. The ATO lists interest on money borrowed to produce assessable income, or to buy income-producing assets, among the operating expenses a business can deduct, and what counts is what the borrowed money was used for. The principal you repay is not a deduction, because it pays back the money you borrowed, and when part of a loan paid for private things only the business share of the interest is claimed. The calculator totals the interest for each income year, 1 July to 30 June. This is general information from the ATO’s guidance, read on 12 November 2026, not tax advice for your situation.

In Australia, a comparison rate is a single percentage that includes a loan’s interest rate and most of its fees and charges, so two loans can be compared on their true cost. ASIC’s Moneysmart notes that a comparison rate is only accurate for the example the lender used, so compare offers on the same loan amount and term. Put a loan’s fees under More options and the calculator gives the same kind of figure on your own amount and term: a $20,000 personal loan at 12% with a $250 upfront fee and $10 a month costs the same as a 13.92% loan with no fees.

Repayments are rounded to the cent, and the part-cents add up over the term. Rather than leave a few cents owing, the last repayment is whatever clears the balance plus that period’s interest, so the schedule ends at exactly zero. On $50,000 at 8.5% over 5 years, the 60th monthly repayment is $1,025.57 instead of $1,025.83. With a balloon, the last repayment also carries the balloon.