Deposit
10% of £300,000 is £30,000.
MORTGAGE GUIDE
What is a 10% deposit on a £300,000 house?
A 10% deposit is £30,000. That leaves a £270,000 mortgage before other buying costs. The simple arithmetic is easy; the useful planning question is what the deposit does to the rest of the transaction.
THE NUMBERS
£30,000 deposit + £270,000 mortgage = £300,000 property.
Mortgage
The remaining purchase price is £270,000, before any financed fees or other transaction effects.
LTV
The starting loan-to-value is 90% because the mortgage is 90% of the property price.
Useful comparison: increasing the deposit to £60,000 would leave a £240,000 mortgage and an 80% starting LTV. The mortgage calculator can then show how the different balance changes the monthly payment and total interest under the same rate and term.
DO NOT USE EVERY POUND AS DEPOSIT
The cash needed to buy can be more than the deposit.
Buying a property can involve Stamp Duty where applicable, legal work, surveys, valuation fees, moving costs, insurance and other transaction expenses. It can therefore be risky to assume that all available savings should be committed to the deposit.
Keeping an emergency buffer may also matter after completion. A larger deposit reduces borrowing, but a smaller cash reserve can make the household more vulnerable to an unexpected repair or income disruption.
Use the Affordability Calculator to test the savings buffer →
WHAT 90% LTV MEANS
Loan-to-value is a starting point for comparing mortgage scenarios.
At 90% LTV, the mortgage represents 90% of the property's value under this simple purchase-price model. LTV can affect which products are available and the rate offered, but actual mortgage pricing and eligibility depend on the lender and applicant.
This guide does not predict a lender's offer. Use the actual product illustration when one is available.
FREQUENT QUESTIONS
10% deposit on £300,000 FAQs
Is a 10% deposit always enough to buy?
A 10% deposit may meet the deposit requirement for some products, but lender eligibility, affordability and the rest of the transaction still matter.
Does a larger deposit lower the monthly payment?
It lowers the amount borrowed, so under the same rate and term the modelled monthly payment and total interest are lower.
Should I save for the deposit and emergency fund separately?
That can be a useful way to avoid using every available pound on the purchase. The appropriate reserve depends on the household's circumstances.
Model the £270,000 mortgage → · Estimate Stamp Duty →
Illustrative information only. Mortgage products and eligibility vary by lender.
THE DEPOSIT IS NOT THE WHOLE PURCHASE BUDGET
A £30,000 deposit leaves a £270,000 mortgage, but you still need cash for the transaction and life after completion.
Ten per cent of £300,000 is £30,000. The resulting 90% loan-to-value is a useful starting point for mortgage modelling, but it does not tell you whether the purchase is affordable or what rate a lender will offer.
Before completion
Allow for costs such as property tax where applicable, legal work, surveys, moving costs and other transaction expenses rather than assuming every saved pound belongs in the deposit.
After completion
A cash reserve can help cover repairs, household shocks or a temporary income drop. A larger deposit is not automatically more useful if it leaves no accessible buffer.
Mortgage comparison
Use the £270,000 borrowing figure with different rates and terms to see how the monthly payment and total interest change. Then compare that with the household's actual net income and spending.
MoneyHelper notes that mortgage affordability can involve regular household spending and existing debts, and that deposits can affect borrowing and mortgage pricing. MoneyHelper mortgage affordability guidance →