Saving for a house deposit is one of the largest financial targets most people set, and one of the hardest to plan around accurately. The deposit percentage gets most of the attention, but the total cash needed at completion is typically several thousand pounds higher once stamp duty, legal fees, surveys, and moving costs are added. Planning around the deposit figure alone is a common reason buyers find themselves short at the point it matters most.

This tool calculates how long it will take to save your deposit at your current monthly saving rate, then adds the full upfront cost picture, shows the LTV band your deposit puts you in, and runs an income affordability check against the mortgage you would need. It also models shared ownership at 75%, 50%, or 25% shares. All figures are illustrative and depend on the inputs you provide. Stamp duty figures apply to England and Northern Ireland only.

About this tool

How to use the house deposit planner

Working through the inputs in order gives the most complete picture. Each section of the tool builds on the previous one, so it is worth reading the results at each stage before moving to the next.

Understanding LTV bands and what they mean for mortgage access

Loan-to-value ratio expresses the mortgage as a percentage of the property’s value. A £180,000 mortgage on a £200,000 property is a 90% LTV. The deposit is the inverse: a 10% deposit produces a 90% LTV. Lenders organise their mortgage products into bands based on LTV, and the range of products available, and the rates attached to them, tends to be different at different points on the LTV spectrum. The broad pattern is that a wider range of products is available at lower LTV bands, and rates at those bands are typically lower, reflecting the reduced risk to the lender when the borrower has a larger equity stake relative to the loan.

The bands the tool uses as reference points are 95%, 90%, 85%, 80%, 75%, and 60% LTV. At 95%, only a limited number of lenders typically offer products, and rates are generally higher than at lower LTVs. At 90%, the market widens somewhat. At 80% and below, most mainstream lenders are active and rates tend to improve further. The 60% LTV band is often where the most competitive rates are concentrated, reflecting the very low risk to the lender at that level. The tool shows how much extra deposit is needed to cross from your current band into the next lower one, which can help in deciding whether to save longer before buying or to proceed with the current deposit level.

The true upfront cost of buying a home

The deposit is the largest single cash outlay in a property purchase, but it is not the only one. Several other costs fall due at or before completion, and planning around the deposit figure alone without accounting for these is a common cause of under-preparation. The tool adds four categories of illustrative costs to the stamp duty calculation to produce a total estimated cash requirement. All four are shown as ranges because the actual costs depend on the specific property, the solicitor and surveyor chosen, the lender’s product, and the logistics of the move.

Solicitor fees for a residential purchase typically fall between £1,500 and £3,000, covering conveyancing for the buyer and lender. A survey ranges from £400 for a basic valuation to £1,500 or more for a full structural survey on an older or higher-value property. Mortgage arrangement fees vary widely: some products carry no arrangement fee while others charge up to £2,000, and this fee is sometimes added to the mortgage rather than paid upfront, though doing so means paying interest on it over the full mortgage term. Removal costs are typically £500 to £2,000 for a local move, rising for longer distances or larger volumes. Understanding the full cash requirement well before exchange means the final months of saving can target the realistic completion figure rather than just the deposit.

The income affordability check explained

The affordability sense check multiplies household income by 4.5 and compares the result against the mortgage you would need, calculated as the effective purchase price minus the deposit. A multiplier of 4.5 times income is commonly cited as a reference point in UK mortgage lending, and many mainstream lenders use it as a starting point for affordability assessment. It is not a lending criterion and it does not account for the many other factors that lenders consider, including existing credit commitments, monthly outgoings, credit history, and the specific product criteria of the lender.

The tool colours the panel green, amber, or red based on the ratio of the mortgage needed to the 4.5 times income figure. Green indicates the mortgage is comfortably within this illustrative range. Amber suggests it is approaching or slightly above the commonly applied level, which does not preclude approval but may mean the application requires a lender with a more flexible affordability approach. Red indicates the mortgage is materially above the 4.5 times figure, which is a signal worth noting early. Some lenders do lend above this level in certain circumstances, but it is a prompt to consider whether the property price target, the deposit level, or the income figure needs to be adjusted before making a formal application.

Shared ownership and how the deposit calculation changes

Shared ownership schemes allow buyers to purchase a percentage of a property and pay rent on the remainder, with the option to buy additional shares over time through a process called staircasing. The deposit and mortgage are calculated on the share being purchased rather than the full property value. A 25% share of a £300,000 property has an effective purchase price of £75,000, and the deposit and mortgage are calculated on that figure. This significantly reduces the cash required to enter the market, which is the primary reason shared ownership is used, but it also means the total monthly cost includes both mortgage payments and rent on the unowned share.

The tool adjusts all calculations, including stamp duty, when a shared ownership percentage is selected. The contextual panel that appears explains the rent payable on the unowned portion, typically calculated as a percentage of the unsold equity, so the full monthly commitment is visible alongside the deposit saving timeline. Stamp duty on shared ownership purchases has its own set of rules, and the calculation in this tool applies the standard SDLT treatment for the share being purchased. For a detailed SDLT breakdown across all buyer types and nations, the stamp duty calculator covers each scenario in full.

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Frequently asked questions

How much deposit do I need to buy a house?

The minimum deposit for most residential mortgage products in the UK is 5% of the purchase price, which corresponds to a 95% LTV. At this level, the number of lenders offering products is smaller and rates are typically higher than at lower LTV ratios. A 10% deposit (90% LTV) broadens the range of available products meaningfully. A 15 to 20% deposit (80 to 85% LTV) opens the market further. First-time buyer government schemes such as the Mortgage Guarantee Scheme have at various times supported 5% deposit mortgages more widely, though the availability of specific schemes changes and is worth checking on GOV.UK.

Beyond the mortgage product implications, the deposit size affects the mortgage amount and therefore the monthly payment. A larger deposit reduces the loan, which reduces monthly payments, and in many cases produces a lower interest rate on a better LTV product as well. The LTV band panel in this tool shows the extra deposit needed to move to the next lower band, which can help in deciding whether saving a little longer to cross a threshold makes a material difference to the mortgage options available.

How does the stamp duty calculation work in this tool?

The tool calculates Stamp Duty Land Tax (SDLT) for purchases in England and Northern Ireland using April 2025 rates. SDLT is calculated on a marginal basis: different rates apply to different portions of the purchase price above each threshold, not to the full purchase price. For example, if the standard rates produce no SDLT on the first £125,000, 2% on the next £125,000, and 5% above £250,000, a £300,000 purchase would be taxed as: zero on the first £125,000, 2% on the next £125,000 (giving £2,500), and 5% on the remaining £50,000 (giving £2,500), totalling £5,000.

First-time buyer relief raises the zero-rate threshold from £125,000 to £300,000, meaning eligible buyers pay no SDLT on purchases up to that amount, with 5% applying on the portion between £300,001 and £500,000. The tool applies this relief automatically when first-time buyer status is selected. SDLT applies to England and Northern Ireland only. Scotland uses Land and Buildings Transaction Tax (LBTT) and Wales uses Land Transaction Tax (LTT), both with different rates and thresholds. The stamp duty calculator covers all three nations. SDLT rates are subject to change: verify the current rates and your specific eligibility on HMRC’s website before relying on any figure for transaction planning.

What does the 4.5 times income affordability check mean?

The 4.5 times income figure is a commonly cited reference point in UK residential mortgage lending. It suggests that many mainstream lenders will typically consider lending up to 4.5 times a household’s gross annual income, though actual lending decisions depend on a comprehensive affordability assessment that includes monthly outgoings, existing credit commitments, credit history, employment type, and the lender’s own risk criteria. The multiplier is not a regulatory cap and individual lenders apply it differently.

The tool uses this figure as an early-stage indicator only. A green result does not mean a mortgage is guaranteed; it means the borrowing level is within the range that many mainstream lenders commonly consider. An amber or red result does not mean a mortgage is unachievable; it means the amount is approaching or above the commonly applied level, and either a larger deposit, a higher income, or a specialist lender may be required. The result is a prompt for further investigation rather than a definitive assessment of mortgage eligibility.

How does shared ownership affect the deposit I need to save?

With shared ownership, the deposit is calculated on the share of the property being purchased, not the full market value. Buying a 50% share of a £280,000 property means a deposit based on £140,000, which at 10% is £14,000 rather than £28,000. This reduction in the upfront deposit requirement is the main financial advantage of shared ownership for buyers who cannot yet accumulate a deposit based on the full property value. The mortgage is also based on the share price, reducing the monthly mortgage payment compared with buying the full property outright.

The trade-off is that rent is payable on the unowned share. This rent is typically set as a percentage of the unsold equity, commonly around 2.75% per year, though the specific rate depends on the housing association and the property. On a 50% share of a £280,000 property, rent on the remaining £140,000 at 2.75% per year would be approximately £3,850 per year, or around £320 per month. This monthly rent adds to the mortgage payment, so the total monthly housing cost under shared ownership is the combination of both. The tool’s shared ownership panel shows this context so the full monthly commitment is visible alongside the deposit saving timeline.

Should I save a larger deposit or buy sooner with a smaller one?

This is a question the tool can help frame numerically but cannot answer prescriptively, because it depends on factors specific to each buyer’s situation. The main financial considerations are: the rate difference between the mortgage products available at different LTV levels, the cost of renting while saving for a larger deposit, any anticipated change in property prices during the additional saving period, and whether the monthly saving rate could be sustained long enough to meaningfully improve the LTV.

The LTV band panel in the tool makes the financial dimension of this decision concrete. If crossing into the next lower LTV band requires six months of additional saving and the rate saving on the mortgage is meaningful, the calculation may favour saving longer. If reaching the next band requires three or more years of additional saving at the current rate, the cost of renting during that period may outweigh the rate benefit of a lower LTV product. The tool does not model property price inflation or rental costs, so a full comparison would need to factor those in separately.

This tool is for illustrative purposes only and does not constitute financial or tax advice. Stamp duty figures are based on SDLT rates for England and Northern Ireland as at April 2025 and apply to standard residential transactions only; they do not cover Scotland (LBTT), Wales (LTT), or complex transactions including certain shared ownership structures. SDLT rates and thresholds are subject to change: verify current rates and your specific eligibility on HMRC’s website before relying on any figure for transaction planning. The income affordability check uses a 4.5 times income multiplier as an illustrative reference only and does not constitute a mortgage affordability assessment or a guarantee of any mortgage offer. Upfront cost ranges are illustrative and will vary by property, location, lender, and service provider. Actual outcomes will depend on your individual circumstances.