Why the cost per landed link is the only number that matters
A campaign contacting 300 prospects at a 4 % reply rate and a 25 % close rate lands three links. If two people spent fifteen minutes each on research, personalisation and follow-up per prospect, that is 75 hours of work — several thousand euros before a single placement fee. Divide by three and the honest cost per link is an order of magnitude above the quoted price of a placement.
This is why the two levers that matter most are the reply rate and the qualification of the list, not the negotiation on placement price. Going from a 3 % to an 8 % reply rate — better targeting, a genuinely relevant asset, a subject line that says what it is — halves the cost per link without changing a single fee. Buying the same list twice as cheaply does nothing if nobody replies.
Tactics differ structurally. Digital PR has near-zero placement fees and a high asset cost, so it is cheap per link when a campaign lands and catastrophic when it does not. Guest posting and niche edits have predictable per-unit costs and predictable, unremarkable results. Product-led links — a free tool, a dataset, a calculator — have the highest upfront cost and the only cost curve that improves over time, because the asset keeps earning links without further outreach.
Closing a gap you can actually close
The referring-domain gap is the most misused number in link building. Comparing your 180 domains to a national brand's 12,000 produces a target no budget will ever reach, and it is the wrong comparison anyway: what matters is the profile of the pages that outrank you on the specific queries you care about, which is often a much smaller set of much more ordinary sites.
The model assumes your competitor keeps earning links too, at around 1.5 % of their domain count a month, which is why the months-to-close figure can come back as "never". That is not a bug; it is the honest answer to chasing an entity growing faster than you are. When it happens, the productive response is to change the target — a narrower topical cluster where you can plausibly become the most-linked resource — rather than to raise the budget.
Two quality caveats the arithmetic cannot capture. First, links are not interchangeable: one editorially given link from a site that genuinely covers your field outperforms twenty paid placements on generic blogs, and paid links violate Google's spam policies whether or not they are detected. Second, internal linking is free and routinely neglected: before commissioning any campaign, make sure the pages you want to rank are linked from the strongest pages you already own.
- Optimise the reply rate before negotiating placement prices
- Compare against the sites outranking you, not the market leader
- Fix internal linking before buying a single external link
- Prefer one relevant editorial link to twenty generic placements
- Treat a 'never close' result as a signal to narrow the target
- Remember paid links breach Google's spam policies