When investors ask how much money they need to buy an investment property, the conversation usually starts with the deposit. If a lender is prepared to finance 75% of a £300,000 purchase, it is easy to assume that you need £75,000.
In reality, that is only the starting point. Stamp duty, legal fees, mortgage costs, furnishing or refurbishment and the money you should still have available after completion can take the real capital requirement well beyond the deposit. There is also something less predictable to allow for: the numbers you start with do not always survive unchanged through to completion. A lender may value the property differently, use a more conservative rental figure or ultimately offer less borrowing than expected.
The more useful question is therefore not simply, “How much deposit do I need?” It is “How much capital do I realistically need for the whole investment?”
A £75,000 deposit does not mean you need £75,000
Take a £300,000 investment property financed at 75% loan-to-value. The deposit is £75,000.
If it is an additional residential property in England, the current higher SDLT rates would produce a £20,000 stamp duty bill. That takes the immediate requirement to £95,000 before paying a solicitor, arranging the mortgage or preparing the property for a tenant.
Mortgage fees can be more significant than investors expect, particularly where a product carries a percentage-based arrangement fee rather than a fixed charge. Legal costs will vary according to the property and ownership structure, while apartments may involve service-charge payments around completion and houses, particularly older stock, may need more maintenance or refurbishment before letting. A furnished property can introduce another several thousand pounds of expenditure.
None of these costs is unusual; the issue is simply that they are often considered after the investor has already decided what they can afford to buy. That is why the purchase price and deposit should never be looked at in isolation.
What happens if the lender values the property lower?
Another reason to avoid structuring a purchase too tightly is that an agreed price is not a guaranteed mortgage valuation.
A lender's surveyor will form their own view of the property's value and, on many buy-to-let transactions, the achievable rent. Comparable evidence is important, but genuinely identical properties are rare. Two apartments in the same development can differ by floor, outlook, size, condition or specification, while houses on the same road can vary because of extensions, plot size, parking, condition or previous improvements. Recent transactions may also have taken place under different market conditions or included incentives that need to be considered.
Rental evidence can vary in the same way. A local letting agent may reasonably believe a property should achieve £1,500 per month while a lender's valuer is only prepared to rely on evidence supporting £1,400. Neither necessarily has to be wrong; the more important question is whether the investment can cope with the difference.
If a modest change in valuation suddenly creates a deposit shortfall you cannot fund, or a slightly lower rental assessment means the intended mortgage no longer works, the purchase may have been structured too tightly from the outset. Having additional capital available does not mean it all needs to go into the deposit; it simply means you still have options if the numbers move.
Is a below-market-value property really a discount?
Headline discounts deserve the same scrutiny.
Suppose a property that could be worth £200,000 in good condition can be purchased for £160,000. On paper, that looks like a 20% discount. If it then requires £40,000 of refurbishment to bring it to the same standard as the £200,000 comparables, the investor has not really created a £40,000 margin. They have spent £200,000 creating something worth around £200,000, before stamp duty, legal fees, finance, holding costs or any overspend are considered.
That does not automatically make it a poor project; it simply means the advertised discount was not the investor's profit. For refurbishment or BRR strategies, the more useful figure is the all-in cost of producing the finished asset. A property advertised at 20% below its eventual value may need to be bought considerably further below that value before a meaningful margin actually exists.
The same principle applies to developer incentives. Furniture packages, legal contributions and cash incentives can improve the economics of a good investment, but they should not be used to make an overpriced property appear attractive. The underlying value comes first, and the discount comes afterwards.
How much should I put down on an investment property?
There is no single deposit percentage that is right for every investor.
Someone in their 30s or 40s, still earning well and investing over a long time horizon, may reasonably use a higher loan-to-value and preserve more capital for other investments. Time also gives rental income and property values an opportunity to change, while inflation can reduce the real burden of nominal debt over a sufficiently long period, provided the borrowing remains affordable.
For someone approaching retirement or relying on their portfolio to produce income, the calculation can be very different. Borrowing at 50% or 60% LTV rather than 75% requires more capital upfront, but can materially reduce mortgage costs, improve monthly cash flow and make the income less sensitive to future interest-rate changes.
Recent years have shown why that distinction matters. Some portfolios that produced perfectly acceptable cash flow when borrowing was cheap became much tighter as mortgage rates and other ownership costs increased. The underlying property may still be sound; the amount and cost of the debt can simply leave too little room for the investment to absorb changing conditions.
That does not mean lower leverage is always better. Putting too much capital into one property can leave an investor with insufficient liquidity for unexpected costs or other opportunities. The right deposit should reflect what you need the property to do, which is why someone building wealth over 20 years may sensibly use a different mortgage structure from someone who wants their portfolio to replace employment income today.
How much money should I keep back after buying?
The capital that remains outside the transaction matters as well.
If an investor has £110,000 available and the deposit, stamp duty, legal fees, mortgage costs and setup consume almost exactly £110,000, they may technically have enough to complete, but that does not necessarily mean they have enough to invest comfortably.
Properties can take longer than expected to let, repairs appear, refurbishment budgets move, service charges can change and mortgage pricing may look very different when the property eventually needs refinancing. Keeping a sensible reserve is not about assuming everything will go wrong; it is about making sure one unexpected cost does not force a financial decision you would otherwise choose not to make.
That flexibility becomes particularly valuable during weaker markets. A temporary movement in property values is much easier to live with when the investment continues to produce adequate cash flow and you have enough liquidity to decide when you eventually sell.
So, how much money do you actually need?
For a £300,000 buy-to-let at 75% LTV, £75,000 may be the deposit, but once £20,000 of SDLT and the remaining costs of buying and preparing the property are included, it is entirely realistic for the investor to require more than £100,000 of available capital.
Another investor may deliberately buy the same £300,000 property at 60% LTV. They would need considerably more money upfront, but could benefit from lower borrowing costs and stronger monthly income. Neither structure is automatically better, because they are designed to achieve different things.
Whichever route is chosen, the investment should also be tested against something other than the best-case scenario. What happens if the valuation is slightly lower than expected, the lender uses a lower rent, refurbishment costs increase or the property takes longer to let?
If a purchase only works at the highest valuation, highest rent and lowest possible costs, the problem may not be that you need another few thousand pounds. The margin for error may simply be too small.
At Ethira Property Group, this is why we look at the property, financing and investor's objectives together. Sometimes more leverage makes sense, while in other cases committing more equity produces a better outcome. Occasionally, the numbers are simply too tight and the capital is better kept for another opportunity.
Having enough money to buy an investment property is only the first calculation. The more important question is whether you can afford to own it comfortably.
This article is for general information only and does not constitute financial, tax, legal or mortgage advice. Tax treatment depends on individual circumstances and may change. Different property transaction taxes apply in Scotland and Wales. Mortgage availability, valuations, rates and fees are subject to lender criteria and individual circumstances.