Home Loan Offset Calculator South Africa
See how savings in your FNB Flexi Bond, Standard Bank AccessBond or Nedbank HomeFlex reduce interest and shorten your bond term
| Total interest WITHOUT offset (18 years) | R 1 433 420 |
| Total interest WITH R 150 000 offset balance | R 857 092 |
| Interest saved by offset | R 576 328 |
How an Offset / Access Bond Works
South African banks offer access bonds (FNB Flexi Bond, Standard Bank AccessBond, Nedbank HomeFlex) where money deposited into a linked account reduces the daily outstanding balance on which interest is charged. Your monthly repayment stays the same, but more of it goes to principal each month — shortening the term and saving interest.
The key advantage: the money in the offset account is fully liquid — you can withdraw it at any time for emergencies, unlike a lump sum payment which is harder to access. The interest saving is equivalent to earning the bond interest rate (currently 10.25%) tax-free on your savings.
With R 150 000 in your offset account, you are effectively earning 21.35% p.a. risk-free, tax-free — since bond interest is paid with after-tax money.
| Offset Balance | Monthly Saving | Total Interest Saved | Months Saved |
|---|---|---|---|
| R 0 | R 0/mo | R 0 | 0 mo |
| R 50 000 | R 1 088/mo | R 234 961 | 19 mo |
| R 100 000 | R 1 956/mo | R 422 572 | 34 mo |
| R 150 000 | R 2 668/mo | R 576 328 | 47 mo |
| R 200 000 | R 3 263/mo | R 704 703 | 57 mo |
| R 300 000 | R 4 195/mo | R 906 113 | 74 mo |
| R 500 000 | R 5 403/mo | R 1 167 028 | 95 mo |
| R 1 000 000 | R 6 560/mo | R 1 417 016 | 116 mo |
How Home Loan Offset Accounts Work in South Africa How to use • SA products • Example
How to Use This Calculator
Enter your current bond balance, remaining term, and offset account balance. The calculator shows how much interest you save over the life of the loan and by how many months your bond term is shortened — while keeping your monthly payment unchanged.
Use the Offset vs Extra Payment tab to compare keeping money in the offset account versus making a lump sum payment or saving separately. The key question is always: does the interest saving outweigh the cost of reduced liquidity?
Note: this calculator addresses saving into your access facility (reducing the interest you pay). The separate Access Bond Calculator addresses borrowing from your access facility.
South African Offset Bond Products
South African banks do not use the term "offset mortgage" (common in the UK and Australia) but offer functionally identical products under different names:
- FNB Flexi Bond — your home loan and a linked transactional account work together; money in the account reduces the daily balance on which interest accrues. You can set up salary deposits and debit orders from the same facility.
- Standard Bank AccessBond — the access portion is treated as a revolving credit facility; money deposited reduces the outstanding balance and therefore the daily interest calculation.
- Nedbank HomeFlex — similar structure; the bond and access savings act as one revolving credit account up to the approved limit.
- Absa FlexiReserve — allows overpayments and access to the overpaid amount; functions similarly to an offset.
All these products charge bond-rate interest only on the net balance (bond balance minus savings balance). This is effectively the same as earning the bond interest rate on your savings — currently 10.25% for a standard prime-linked bond.
Worked Example
Pieter has an FNB Flexi Bond with an outstanding balance of R1,200,000 and 18 years remaining at 10.25%. His monthly repayment is approximately R11,890. He has R150,000 in savings.
If Pieter deposits his R150,000 into the Flexi Bond access facility:
- Daily interest is charged on R1,050,000 (R1.2M − R150K), not R1.2M
- The R150,000 is still his — he can withdraw it any time
- He saves approximately R350,000–R400,000 in interest over 18 years
- His bond is paid off roughly 18–24 months earlier
- The effective return on his R150,000 savings = 10.25% (bond rate), tax-free
Pieter compares this to putting R150,000 in a money market account at 8.5% p.a. (taxable). After the R23,800 interest exemption, he'd pay tax on the excess — reducing the effective return. The Flexi Bond offset is clearly superior.
Frequently Asked Questions
What is the difference between an offset bond and an access bond in South Africa?
These are often the same product but discussed from different angles. When you put money in (saving into the access facility to reduce interest), it's called an offset. When you take money out (borrowing against the access facility you've built up), it's called using your access bond. Products like FNB Flexi Bond, Standard Bank AccessBond, and Nedbank HomeFlex allow both: you can save into them to reduce interest, and draw down the available credit when needed.
Is the interest saving on an offset bond tax-free?
Yes, in a practical sense. The saving works by reducing the interest you pay rather than earning interest that is then paid to you. Since you are not earning interest (you are just paying less of it), there is no taxable income arising from the offset. By contrast, a savings account earning 8.5% generates taxable interest income (subject to the R23,800 annual exemption for under-65s). For most earners, the effective after-tax return on a savings account is significantly lower than the bond rate, making the offset more attractive.
Should I pay extra into my bond or keep the money in an offset account?
The interest saving is identical in both cases (paying extra off the bond vs keeping it in the offset/access account). The difference is liquidity. Money in the offset account is immediately accessible. Extra bond payments are technically accessible via the access facility, but you need to apply — and access is subject to bank approval and available credit. For people with stable income and no emergency fund concerns, a lump sum payment is fine. For those who want the safety net of accessible savings, the offset account is better.
Are there any fees for using an access bond or offset facility?
Most SA banks charge a slightly higher interest rate for access bonds (typically prime + 0.25% to prime + 0.5%) compared to a standard bond (which might be prime or prime + a margin). This premium is the "cost" of the flexibility. However, if you consistently keep a meaningful balance in the offset account, the interest saving from offsetting will far exceed this rate premium. Compare the quoted rate before signing up and run the calculation with the actual rate, not prime.
Can I use my salary account as an offset for my bond?
Yes — this is actually the optimal strategy. With an FNB Flexi Bond, you can direct your entire salary into the bond account each month, then draw down for expenses as needed. For the portion of the month when your salary sits in the account before you spend it, interest is charged on a lower balance. Even if your salary is spent by month-end, you save a few days of interest each month — which adds up materially over 20 years. The same logic applies to Standard Bank's AccessBond.