Repo 7.25%/Prime 10.75%
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SARB Prime 10.75% Benchmark • NCA CompliantMonthly + Lump Sum + 13th Cheque Engine

Extra Bond Payment & Lump Sum Payoff Calculator (South Africa)

Model how recurring extra monthly payments, once-off capital lump sums, and annual December 13th-cheque contributions compress your 20 or 30-year South African mortgage schedule and eliminate hundreds of thousands of Rands in compound bank interest.

South African Bond Accelerator

1. Base Home Loan Details

R1 800 000
R
10.75%
%
Loan Term (Years)

2. Configure Payoff Strategy

Strategies combine automatically
Paid directly into capital every month alongside your normal debit order
R1 500/mo
R0 / moR2 500 / moR5 000 / mo
R
Accelerated Payoff Impact Dashboard

Your Home Loan Freedom Forecast

Interest Saved

R943 833

R943 833 Saved
Term Shortened

5 Yrs, 10 Mos

Cut by 5 Yrs, 10 Mos
New Payoff Time

14 Yrs, 2 Mos

Paid off in 14 Yrs, 2 Mos

Standard Loan Cost vs. Accelerated Strategy Cost

Capital (R1 800 000)Interest PaidInterest Eliminated
Standard 20-Year Bond (240 mos)Total: R4 385 789 (Interest: R2 585 789)
Capital
Interest: R2 585 789
Accelerated Payoff Strategy (170 mos)Total: R3 441 956 (Interest: R1 641 956)
Capital
R1 641 956
Saved R943 833
Required InstalmentR18 274/mo
New Monthly OutflowR19 774/mo
Total Extra MonthlyR255 000
Total Lump Sums PaidR100 000

Guaranteed Tax-Free Return Equivalent: Every Rand paid directly into your bond saves interest at 10.75% p.a. after-tax — equivalent to earning over 16.80% p.a. in a taxable savings account for a 36% marginal tax bracket earner.

Interactive Amortisation Ledger

Accelerated Bond Repayment Schedule (170 Months / 15 Years)

YearOpening BalanceNormal RepaymentsExtra + Lump SumsInterest ChargedCapital RepaidClosing Balance
Year 1 (M1–M12)R1 800 000R219 289+R78 000R191 277R106 013R1 693 987
Year 2 (M13–M24)R1 693 987R219 289+R28 000R179 302R67 988R1 626 000
Year 3 (M25–M36)R1 626 000R219 289+R28 000R171 622R75 667R1 550 332
Year 4 (M37–M48)R1 550 332R219 289+R28 000R163 075R84 215R1 466 117
Year 5 (M49–M60)R1 466 117R219 289+R28 000R153 562R93 727R1 372 390
Year 6 (M61–M72)R1 372 390R219 289+R18 000R142 975R94 315R1 278 075
Year 7 (M73–M84)R1 278 075R219 289+R18 000R132 321R104 968R1 173 107
Year 8 (M85–M96)R1 173 107R219 289+R18 000R120 464R116 825R1 056 281
Year 9 (M97–M108)R1 056 281R219 289+R18 000R107 268R130 022R926 260
Year 10 (M109–M120)R926 260R219 289+R18 000R92 581R144 709R781 551

National Credit Act (NCA) Note: South African commercial banks calculate home loan interest daily on the outstanding balance and capitalise it monthly. When paying a large lump sum, always instruct your bank (via your banking app or home loan desk) to keep your monthly debit order unchanged so that your loan term is shortened rather than your monthly instalment being recalculated downward.

The Compounding Math of South African Bonds

All major South African retail banks—including First National Bank (FNB), Standard Bank, Absa, Nedbank, SA Home Loans, and Investec—calculate residential mortgage interest using the daily reducing balance method, capitalised monthly onto your loan account. At the end of every calendar day, your bank computes that day's interest charge as:

SA Bank Daily Interest Formula (365-Day Convention):

Daily Interest = (Closing Daily Capital Balance × Annual Nominal Rate) ÷ 365

At the current SARB Prime Lending Rate of 10.75% p.a., a R1 800 000 bond accrues R554.79 in interest every single day (roughly R16 875 in Month 1) out of a R18 887 total monthly debit order.

Because a standard 20-year (240-month) or 30-year (360-month) bond is structured as an equal-instalment annuity, the amortisation curve is heavily front-loaded with interest. During the first 7 years of a 20-year bond at 10.75% Prime, between 78% and 89% of your mandatory payment is consumed by bank interest, leaving only a fraction to reduce the principal debt.

When you pay an extra R1 500 per month—or inject a once-off lump sum early in the loan lifecycle—100% of that extra Rand bypasses interest and directly reduces your capital balance. That lower capital balance then generates less daily interest tomorrow, next month, and for every remaining year of the bond, creating a reverse-compounding snowball that eliminates years of tail-end instalments.

The “13th Cheque” December Strategy vs. Taxable Savings

For salaried South African professionals who receive an annual performance bonus or 13th cheque in November or December, channeling even a portion of that windfall into your home loan is one of the highest risk-free after-tax investments available in the Republic.

R1 800 000 Bond @ 10.75% Prime (20 Yrs)Standard Bond+R20 000 Annual Bonus (Yrs 1–10)
Total Annual Bonus ContributedR0R200 000
Cumulative Bank Interest PaidR2 732 786R2 089 410
Net Interest Saved & Term CutBaseline (20 Yrs)R643 376 Saved (3 Yrs, 6 Mos Cut)

Why does paying into your bond beat a typical South African fixed deposit or money market account? Once you exceed the SARS annual interest exemption (currently R23 800 per tax year for taxpayers under 65, or R34 500 for those 65 and older), interest earned in a bank savings account is taxed at your marginal personal income tax rate (up to 45%). By contrast, saving 10.75% interest on your home loan is completely tax-free—meaning a taxpayer on a 39% marginal bracket would need to earn a guaranteed 18.44% pre-tax return in a taxable account just to match the net wealth effect of paying down a bond at Prime.

Access Bonds vs. Paying Directly into the Loan (Plus SARS Rental Tax Rules)

Most South African lenders offer revolving Access Bond facilities (such as FNB Flexi Option, Standard Bank AccessBond, Absa FlexiReserve, and Nedbank NedRevolve). Any extra monthly payment or lump sum deposited into an enabled access bond immediately reduces your daily interest calculation while remaining available for instant electronic withdrawal if an emergency arises.

Primary Residence (Access Bond Advantage)

Interest on your primary home is a private domestic expense and cannot be deducted for SARS tax purposes. Parking your emergency fund and surplus cash inside your primary residence access bond gives you instant liquidity while earning a tax-free return equal to your mortgage rate.

Buy-to-Let Property (SARS Section 11(a) Warning)

On an income-generating rental property, bond interest is tax-deductible against rental income under Section 11(a) and Section 24J of the Income Tax Act. However, if you deposit surplus cash into a rental access bond and later withdraw it for personal use (e.g. buying a private car), SARS disallowance rules state that the interest on the redrawn portion is no longer tax-deductible.

Frequently Asked Questions: Extra Bond Payments in South Africa

Can my bank penalize me for paying extra into my bond?
No. Under the South African National Credit Act (Act 34 of 2005), commercial banks (FNB, Standard Bank, Absa, Nedbank, SA Home Loans, and Investec) are prohibited from charging penalty fees when you make extra monthly payments or deposit once-off lump sums into a variable-rate residential home loan. Note that under Section 125 of the NCA, a 90-day early termination notice only applies when you intend to settle the final rand and formally cancel the mortgage bond in the Deeds Office on a large credit agreement (exceeding R250 000)—never for routine extra deposits into an active bond.
Is it better to pay R500 extra every month or R6 000 once a year?
Paying R500 extra every month saves more interest than paying a single R6 000 lump sum at the end of each year. Because South African banks calculate bond interest daily on your closing capital balance (Outstanding Balance × Annual Rate ÷ 365) and capitalise it monthly, your first R500 deposit in Month 1 immediately begins reducing daily interest for the remaining 11 months of that year. The saving depends on your balance, interest rate and when each payment is made. Compare the options in the calculator above.
How do I instruct my bank to reduce the term instead of lowering the monthly instalment?
When you pay a recurring extra monthly amount via debit order or EFT into your home loan, your required minimum instalment normally stays fixed and your loan term automatically shortens. However, when you deposit a large once-off lump sum, some South African banks automatically re-amortise the reduced balance over the original remaining term—lowering your monthly debit order instead of shortening the loan. To prevent this, phone your bank’s Home Loans division or select "Keep Monthly Instalment Unchanged / Reduce Loan Term" in your banking app immediately after making the lump sum deposit.
Should I keep my bond open with a small balance once it is nearly paid off?
Many South African property owners deliberately leave a nominal balance of R1 000 to R5 000 in their access bond rather than formally cancelling the bond at the Deeds Office. Keeping the facility open preserves instant access to your prepaid capital at the Prime lending rate and avoids paying R4 500 to R6 500 in bond cancellation attorney fees until you eventually sell the property (though you will continue paying the statutory R69/month NCA bank administration fee while the account remains open).