Fixed vs Tracker: Which Buy-To-Let Mortgage is Best in 2025?

With mortgage pricing shifting and lender criteria evolving, many landlords are weighing up whether to fix for certainty or track the Bank of England base rate for potential savings. There is no one-size-fits-all answer. The right choice depends on cashflow, risk tolerance, portfolio plans and refinancing flexibility. This article sets out how both options work, the trade-offs to consider, and a simple decision framework you can apply to your own portfolio.

What is a Fixed Rate Buy-To-Let Mortgage?

A fixed rate holds the pay rate steady for a set period, usually two, three or five years. Your monthly interest cost remains predictable for the fixed term. This aids budgeting, supports stress testing in some cases and can de-risk your cashflow during refurbishments or tenant changes. At the end of the fixed period, you can remortgage, product transfer or roll to the lender’s reversion rate.

What is a Tracker Buy-To-Let Mortgage?

A tracker links to the Bank of England base rate plus a margin. Payments move up or down as the base rate changes. Trackers often have lower or zero early repayment charges, which can be attractive if you plan to refinance or sell within a short window. The trade-off is payment volatility. If rates rise, repayments increase. If rates fall, you benefit immediately.

How Lenders Structure Fixed and Tracker Deals

• Term choices: most common are two, three and five years. A few lenders offer seven or ten year fixes.
• Fees: fixed and tracker products may include percentage-based arrangement fees. Lower rates often come with higher fees.
• Repayment type: interest-only remains common for landlords. Capital repayment options exist and can help reduce risk over time.
• ERCs: fixed rates usually carry early repayment charges during the fixed period. Trackers may have none or short ERCs.
• Flexibility: trackers sometimes allow unlimited or larger overpayments. Fixed products tend to cap overpayments each year.

Pros and Cons at a Glance

Worked Examples: Same Property, Different Choices

Assumptions: £200,000 property. £150,000 interest-only loan. Monthly rent £1,150. Fees ignored for simplicity.

Example A: Five-year fixed at 5.25%
Monthly interest = £150,000 × 5.25% ÷ 12 = £656.25. Payments are stable through the fixed term. If your lender stress tests five-year fixes at pay rate, affordability may be easier to evidence.

Example B: Tracker at base + 1.25%
If base rate is 4.75%, pay rate = 6.00%. Monthly interest = £150,000 × 6.00% ÷ 12 = £750. If base rate drops to 4.25%, pay rate becomes 5.50%, and monthly interest falls to £687.50. If base increases, the reverse applies.

Takeaway: the fixed rate wins on certainty and often on the affordability calculation for longer fixes. The tracker can win if you expect cuts soon and you value low or no ERCs for near-term refinancing or disposal.

When a Fixed Rate Makes Sense

• You want predictable payments to protect cashflow on thinner-yielding assets.
• You prefer to avoid fluctuations while undertaking works or tenant transitions.
• You need a five-year fix to meet a lender’s affordability approach at pay rate.
• You are happy to trade flexibility for certainty during the fixed term.

When a Tracker Rate Makes Sense

• You anticipate rate reductions and want to benefit without waiting for a new deal.
• You plan to refinance, restructure or sell within 6 to 24 months and want light ERCs.
• You have strong rental cover, so short-term fluctuations are manageable.
• You value overpayment flexibility to reduce interest if cashflow allows.

Common Pitfalls to Avoid

• Chasing the headline rate. A cheaper rate with a large percentage fee can be more expensive overall. Always compare total cost of credit.
• Locking in too soon. If you plan to restructure the portfolio or dispose of units, ERCs can become a drag on agility.
• Underestimating volatility on trackers. Build headroom. Model downside scenarios, not just hoped-for rate cuts.
• Ignoring lender policy nuances. Affordability methods, overpayment rules and valuation approaches vary by lender.

Decision Framework for Landlords

1. Define your horizon. Is your plan stable for the next three to five years, or are you expecting changes such as refurbishments, sales or incorporations?
2. Test cashflow stress. Model payment sensitivity at plus or minus 1.0% on trackers. Ensure resilience.
3. Assess ERC risk. If flexibility is valuable, lighter ERCs may outweigh a small rate premium.
4. Consider portfolio effects. Will a five-year fix at pay rate unlock affordability for other refinances?
5. Compare total cost. Include arrangement fees, valuation, legal and potential overpayment benefits.

Case Study: Two Landlords, Two Sensible Choices

Landlord 1: Stability first
Owns four flats with modest yields. Refinancing risked failing affordability at higher stress rates. A five-year fix at a competitive pay rate satisfied the lender’s approach and locked in predictable payments. The portfolio passed, and cashflow is stable for the medium term.

Landlord 2: Flexibility first
Holds mixed assets and plans to dispose of a low-yield unit within a year. A tracker with no ERCs enabled overpayments and a quick exit when the sale completed. When pricing improved, they switched without penalty, trimming annual interest cost.

Practical Next Steps

• Gather tenancy schedules, rental statements and your latest portfolio spreadsheet.
• Model both fixed and tracker scenarios, including fees and stress test outcomes.
• Decide the value of certainty versus agility for each property rather than defaulting to a single approach across the portfolio.
• Shortlist lenders based on their affordability method, ERCs and overpayment rules, not rate alone.

Speak to Our Sponsor

Choosing between fixed and tracker is not just about the headline rate. It is about affordability, flexibility and your wider portfolio plan. Our sponsor works daily with landlords to compare total costs, model different paths and identify lenders whose criteria align with your objectives.

Publication date: Monday, 8 September 2025