{
  "$schema": "https://soudcoh.com/tools/data/index.json",
  "slug": "impression-share-calculator",
  "name": "Impression share and missed leads",
  "category": "Budget and forecasting",
  "url": "https://soudcoh.com/tools/impression-share-calculator",
  "dataUrl": "https://soudcoh.com/tools/data/impression-share-calculator.json",
  "currency": "AUD",
  "updated": "2026-08",
  "summary": "Turn Google Ads impression share and lost impression share into the enquiries you missed, split between the ones more budget would buy and the ones it would not.",
  "whatItDoes": [
    "Scales your current enquiries up to what full coverage of the same searches would have produced.",
    "Splits the gap into the part you lost to budget and the part you lost to ad rank, because only one of them is for sale.",
    "Prices the budget-attributable half at your own cost per lead, so the answer is a spend decision rather than a statistic."
  ],
  "howToUse": [
    "In Google Ads, add the columns Search impression share, Search lost IS (budget) and Search lost IS (rank) to your campaign view for the same period you are reporting on.",
    "Enter all three, plus the enquiries and cost per enquiry for that period.",
    "Read the budget-attributable line. That is the only part of the gap a bigger budget will close.",
    "Ignore the rank-attributable line as a spending decision — it is a relevance and quality problem, not a funding one."
  ],
  "formula": [
    "Enquiries at full coverage = enquiries ÷ impression share",
    "Missed enquiries = enquiries at full coverage − enquiries",
    "Budget-attributable = missed × lost-to-budget ÷ (lost-to-budget + lost-to-rank)",
    "Cost to capture = budget-attributable × cost per enquiry"
  ],
  "interpret": [
    "Lost impression share to budget is the clearest buy signal in a Google Ads account. It means the auction was there, you qualified, and the money ran out.",
    "Lost impression share to rank is not solved with money. It is bid, ad relevance and landing page — and raising bids to fix it raises the cost of every click you were already winning.",
    "Full impression share is almost never the goal. The last 20% is the dearest and least relevant fifth of the auction, and it will drag your cost per enquiry up with it."
  ],
  "limitation": "This assumes the impressions you missed would have converted at the rate the ones you won did. They would not — the searches you lose on rank tend to be the ones you match worst. Read the answer as a ceiling on the opportunity, not as a forecast.",
  "inputs": [
    {
      "key": "impressionShare",
      "label": "Search impression share",
      "kind": "percent",
      "default": 45,
      "min": 1,
      "max": 100,
      "unit": "percent",
      "help": "The share of available impressions your ads received. Straight from the Google Ads column.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "lostBudget",
      "label": "Search lost IS (budget)",
      "kind": "percent",
      "default": 35,
      "min": 0,
      "max": 100,
      "unit": "percent",
      "help": "The share you missed because the daily budget ran out.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "lostRank",
      "label": "Search lost IS (rank)",
      "kind": "percent",
      "default": 20,
      "min": 0,
      "max": 100,
      "unit": "percent",
      "help": "The share you missed because your ad rank was too low to show.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "leads",
      "label": "Enquiries in the period",
      "kind": "number",
      "default": 40,
      "min": 1,
      "max": 1000000,
      "unit": "count",
      "help": "Same period as the impression share figures.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "cpl",
      "label": "Cost per enquiry",
      "kind": "currency",
      "default": 90,
      "min": 0.5,
      "max": 100000,
      "unit": "AUD",
      "help": "Same period again. The cost per lead calculator works this out if you do not have it.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "closeRate",
      "label": "Enquiries that become work",
      "kind": "percent",
      "default": 30,
      "min": 0.1,
      "max": 100,
      "unit": "percent",
      "help": "Used to convert missed enquiries into missed jobs.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    },
    {
      "key": "jobValue",
      "label": "Average job value",
      "kind": "currency",
      "default": 1200,
      "min": 1,
      "max": 10000000,
      "unit": "AUD",
      "help": "Average invoice excluding GST.",
      "sourceId": null,
      "sourceNote": null,
      "options": null
    }
  ],
  "defaults": {
    "impressionShare": 45,
    "lostBudget": 35,
    "lostRank": 20,
    "leads": 40,
    "cpl": 90,
    "closeRate": 30,
    "jobValue": 1200
  },
  "exampleResult": {
    "headline": {
      "label": "Enquiries lost to budget",
      "value": "31.1",
      "note": "About $2,800 to buy them, worth $11,200 of work"
    },
    "outputs": [
      {
        "label": "Enquiries at full coverage",
        "value": "88.9",
        "note": "Against 40 today"
      },
      {
        "label": "Total enquiries missed",
        "value": "48.9",
        "note": "At 45% impression share"
      },
      {
        "label": "Lost to ad rank",
        "value": "17.8",
        "note": "Not buyable with budget"
      },
      {
        "label": "Jobs missed to budget",
        "value": "9.3",
        "note": "At 30% closing"
      }
    ],
    "workings": [
      {
        "label": "Enquiries at full coverage",
        "expression": "40 ÷ 45% = 88.9"
      },
      {
        "label": "Missed",
        "expression": "88.9 − 40 = 48.9"
      },
      {
        "label": "Share of the loss that is budget",
        "expression": "35% ÷ (35% + 20%) = 63.6%"
      },
      {
        "label": "Lost to budget",
        "expression": "48.9 × 63.6% = 31.1"
      },
      {
        "label": "Cost to capture",
        "expression": "31.1 × $90.00 = $2,800"
      }
    ]
  },
  "shareableExample": "https://soudcoh.com/tools/impression-share-calculator?impressionShare=45&lostBudget=35&lostRank=20",
  "faqs": [
    {
      "question": "What is a good impression share in Google Ads?",
      "answer": "There is no published figure for this in any market and we are not going to make one up. What the number tells you is more useful than a target anyway: if your lost impression share to budget is large, the auction wanted to show your ads and the money stopped it, and that is a straightforward buy. If it is small and lost-to-rank is large, impression share is a symptom of relevance and no budget will move it."
    },
    {
      "question": "Should I aim for 100% impression share?",
      "answer": "Almost never. The last portion of an auction is the dearest and the least relevant, so the cost per enquiry rises as you approach full coverage. On a service account that money is usually better spent on more search terms, a wider service area, or a second channel. The exception is a small, tightly defined, high-value keyword set — emergency work in one suburb — where owning the auction outright can be worth the premium."
    },
    {
      "question": "How do I find impression share in Google Ads?",
      "answer": "Open the Campaigns view, click Columns, and add Search impression share, Search lost IS (budget) and Search lost IS (rank) from the Competitive metrics group. Set the date range you want to analyse before you read them, and take all three from the same range and the same campaigns — mixing ranges is the most common reason the three do not add up to 100%."
    },
    {
      "question": "Can I use impression share to estimate a competitor's spend?",
      "answer": "No, and any tool that claims to is guessing. Impression share tells you what proportion of eligible impressions you received, not how many advertisers took the rest or what any of them paid. The auction insights report will name who else showed on the same searches and how often, which is genuinely useful — but it does not carry a dollar figure and nothing can reconstruct one."
    },
    {
      "question": "My lost impression share to rank is high. What do I do?",
      "answer": "Work on the three things that make up ad rank other than the bid: expected click-through rate, ad relevance and landing page experience. In practice that means tighter match between what people searched and what the ad says, and a page that answers the specific search rather than a homepage. Raising bids does lift rank, but it raises the price of every click you were already winning, so it is the last lever rather than the first."
    }
  ],
  "sources": [],
  "relatedTools": [
    "https://soudcoh.com/tools/google-ads-budget-forecaster",
    "https://soudcoh.com/tools/cost-per-lead-calculator",
    "https://soudcoh.com/tools/channel-mix-calculator"
  ],
  "licence": {
    "terms": "Free to reuse with attribution to SoudCoh and a link to the page it came from. Third-party figures remain the property of the publisher named on each row and must keep their market and year attached.",
    "attribution": "SoudCoh — https://soudcoh.com/tools"
  }
}