How earmarkIQ Values Your Property

The biggest number on your balance sheet is usually the stalest

If you own a home in the UK, it is almost certainly the largest single item you own. It is also the item you have the least current information about. Your bank balance is accurate to the minute. Your pension updates daily. Your house was last given a number by a stranger on the day you bought it, possibly years ago, and has been sitting in your mental accounts at roughly that figure ever since.

That gap matters for anyone trying to track net worth honestly. Leave the property out entirely and the number is incomplete, because a decade of mortgage repayment is invisible. Put it in at the purchase price and the number is wrong in a direction that quietly compounds. Update it by hand once a year using whatever a property portal shows and you have introduced a figure whose method you cannot inspect.

earmarkIQ takes a different route, and it is one chosen for transparency rather than for producing the most flattering number. The estimate is built from a published official statistic and a price you already know, using arithmetic you can check on a calculator.

Indexation, step by step

The UK House Price Index is an official statistic published monthly by HM Land Registry, working with Registers of Scotland, Land and Property Services Northern Ireland, and the Office for National Statistics. Two features make it useful here. First, it is built from actual registered sale completions, not from asking prices, so it reflects what people paid rather than what sellers hoped for. Second, it is published broken down by local authority, so the movement it describes is local to your area rather than a national average that would be dominated by London.

earmarkIQ needs three inputs from you: your address, so it knows which local authority index applies; the price you paid; and the month you completed. From there the calculation is one line.

When HM Land Registry publishes the following month's index, earmarkIQ recalculates. You are not asked to do anything, and the figure does not sit frozen between the rare occasions you think to update it.

Two characteristics of the underlying statistic are worth knowing. The index is published with a lag of roughly two months, because sales take time to register. And earlier months are revised as more completions come in, so a figure can shift slightly after it first appears. Neither is a flaw in earmarkIQ; both are properties of a statistic built from real transactions rather than from listings.

Why this is an estimate, and not a valuation

The word matters. A valuation is a professional judgement about one specific property, usually after someone has looked at it, and it carries responsibility. What earmarkIQ produces is an estimate of index movement applied to a known price. It is a different kind of object entirely, and it has three blind spots you should hold in mind.

It cannot see your street. A local authority is a large and varied area. It contains terraces, new-build flats and detached houses, in neighbourhoods that move at different speeds. One average is applied to all of them. If your particular street has run ahead of the district, the estimate understates. If a large new-build development has pulled the local average up, an older property may be overstated.

It cannot see your property. The extension, the loft conversion, the new roof, the rewiring, the kitchen, the damp in the back bedroom: none of it is an input. The only property-specific fact in the calculation is a purchase price from years ago, which described a house that may no longer exist in that form.

It cannot see the market this week. Because of publication lag and revision, the estimate describes where the index was a couple of months back, not where buyers are today.

How indexation differs from an AVM

If you have seen an instant valuation on a property portal, you have met an automated valuation model, usually shortened to AVM. It is a related idea to indexation but a materially different one, and the distinction is worth drawing clearly because the two produce numbers that look identical on screen.

The honest summary is that each is stronger where the other is weak. An AVM is property-specific, which removes the largest source of error in an indexed figure. But its workings are closed to you: you cannot see which comparables it chose or how it weighted them, and you cannot check its arithmetic. Indexation is blind to the individual property, but every input is published and every step is inspectable.

Note the row both approaches share. Neither knows the condition of your home or the work you have done to it. An AVM narrows the geography; it does not walk through your front door. That is the line separating any data-derived estimate from a surveyor's valuation, and no amount of modelling crosses it.

earmarkIQ's standard estimate, on every tier, is indexation. The Pro tier adds an address-level market valuation, calculated for your specific property rather than for the average property across your whole local authority. It sharpens the geography. It does not change what kind of thing the output is: still an estimate produced from data, still something you can override.

When to override the estimate

Because the method has known limits, earmarkIQ lets you replace the figure with your own. This is not a fallback for when the app gets it wrong; it is the correct behaviour whenever you hold better evidence than an indexed purchase price. Reach for it in these situations:

• You have had a survey. A RICS survey or homebuyer report with a valuation in it beats an index calculation outright.
• You have had a lender valuation. A figure from a recent mortgage application or remortgage is a valuation of your specific property by a party with money at stake.
• You have agents' appraisals. Two or three market appraisals, with a sensible midpoint taken, are good evidence — though remember an appraisal is partly a pitch for your instruction.
• A near-identical neighbour has sold. A completed sale on your street for a comparable property is strong evidence. An asking price is not.
• You have just bought. In the first months after completion the price you paid is the best number in existence. There is no index movement worth applying yet.
• You have changed the property. After an extension, a conversion or a full renovation, an indexed purchase price is describing a different house from the one you now own.

Two habits keep an overridden figure honest. Record where it came from and when, because a lender valuation from four years ago has stopped being better evidence than a current index. And revisit it rather than leaving it in place indefinitely: if you have nothing fresher, reverting to the index estimate is often the more truthful option, because at least it keeps moving with the market rather than sitting at a number you liked.

What the number is actually for

The property value is not the point. Equity is. earmarkIQ subtracts your outstanding mortgage balance from the estimated value, and it is the resulting equity — not the gross value — that flows into your net worth alongside your accounts, savings, investments and debts.

That framing keeps the estimate in proportion. Equity grows from two directions: the balance falls every month as you repay, which is certain, and the value moves with the index, which is an estimate. The certain half is the half you control. A net worth figure that rises because the local index moved has not made you better able to pay a bill, and earmarkIQ shows the components separately so you can tell the two apart.

Frequently asked questions