Switching From Fixed to Variable Mid-Term: A Worked Illustration

An illustrative calculation of what moving an existing fixed-profit home finance onto variable pricing costs and saves, and the break-even point that decides it.

Switching pricing type mid-term is not a rate comparison, it is a break-even calculation: the cost of changing today against the saving over the term you have left, under pricing that may move. The arithmetic below is illustrative and uses round numbers to show the method. Your own figures, and the question of whether your contract even permits a switch, come from your lender, and pricing of every kind in this area changes and must be confirmed when you act.

The situation

A borrower is eight years into a twenty-year fixed-profit home finance on a villa. The outstanding amount is SAR 1,200,000 and the current instalment is SAR 11,200 a month. A lender offers to move the arrangement onto variable pricing at a margin that would produce an opening instalment of SAR 10,100 a month on the same remaining term. Switching involves settlement administration with the existing lender, a fresh valuation, and registration steps on the new security. The borrower wants to know whether the move is worth making and what would have to happen for it to go wrong.

Assumptions (illustrative)

• Outstanding amount: SAR 1,200,000.
• Remaining term: 12 years, or 144 months, unchanged by the switch.
• Current instalment on fixed pricing: SAR 11,200 a month.
• Opening instalment on the variable offer: SAR 10,100 a month.
• One-off costs of switching: SAR 26,000 in total, covering settlement administration, valuation and registration.
• Stress assumption: a reset that lifts the variable instalment to SAR 12,300 a month after two years.

Step 1: Measure the monthly saving at the opening rate

SAR 11,200 minus SAR 10,100 equals a saving of SAR 1,100 a month.

This is the only figure the switch is sold on, and it is the least reliable one, because it holds only until the first reset. Treat it as the starting point of the calculation rather than the answer.

Step 2: Find the break-even in months

SAR 26,000 of switching cost divided by SAR 1,100 of monthly saving equals 23.6, so roughly 24 months.

The borrower spends two years simply recovering the cost of moving. Any benefit arrives only from month twenty-five onward, and only if the saving has survived that long.

Step 3: Value the saving over the full remaining term if nothing moves

SAR 1,100 multiplied by 144 months equals SAR 158,400, less SAR 26,000 of cost, leaving SAR 132,400.

This is the best case and the number the offer will emphasise. It assumes the variable rate never resets upward across twelve years, which is an assumption no lender will guarantee.

Step 4: Apply the stress assumption

Two years at SAR 1,100 saved gives SAR 26,400. From month twenty-five the instalment is SAR 12,300, which is SAR 1,100 above the old fixed payment, so the next 120 months cost SAR 132,000 more.

Under this path the borrower is SAR 26,400 ahead when the reset lands and then falls behind at the same rate, ending roughly SAR 131,600 worse off before counting the switching cost.

Step 5: Compute the net position under the stress path

SAR 26,400 of early saving minus SAR 132,000 of later cost minus SAR 26,000 of switching cost equals a net loss of about SAR 131,600.

The two outcomes are roughly symmetrical in size but not in nature: the gain requires nothing to happen for twelve years, while the loss requires one reset to go against the borrower.

Step 6: Find the reset that leaves the borrower level

For the switch to break even over the remaining term, the average instalment across 144 months must not exceed SAR 11,200 minus SAR 180, which is the switching cost of SAR 26,000 spread over 144 months.

The real test is not the opening payment but the average payment the borrower expects across twelve years. If that average is above roughly SAR 11,020, the switch loses money.

What changes the answer

• The remaining term: the same switching cost spread over four remaining years instead of twelve rarely justifies itself.
• Whether the new lender charges the full suite of costs or waives part of the package to win the business.
• How often the new pricing resets, because frequent resets shorten the period your opening saving survives.
• Any cap or per-reset limit in the new contract, which changes the shape of the downside materially.
• Whether the existing lender will reprice to keep you, which is the cheapest possible version of this exercise.

What the numbers tell you

• Break-even in months, not the monthly saving, is the number that decides a switch.
• A switch late in a term is usually a poor trade because the cost has fewer months to amortise over.
• Ask the existing lender to match before you pay to move, because that conversation costs nothing.
• Model the stress path explicitly, and decide whether you could meet the stressed payment at all.
• Get the switching costs itemised in writing from both lenders, because an estimate quoted verbally moves.

Limits of this example

Every figure above is an illustrative assumption used to show the method, not a quote, valuation or market rate. Costs, rates, fees and regulations change and must be confirmed with the relevant authority, lender or supplier before you commit.

Domira works alongside the finance side of a property purchase or a build: the valuation evidence, the cost plan and the construction programme that a lender needs to see. The lending terms come from your bank or finance company, and Domira makes sure the property side of the file stands up.