Cost Per Link: How To Calculate It, Why Vendors Hide It, and What It Actually Means
Every link-building platform quotes a different number. Here's how to calculate the one that matters: cost per link still live at 90 days. And why that number is the only one your CFO should care about.
A vendor quotes you $100 per link. A competitor quotes $75. A third quotes $50 and calls it 'cost-effective.' But they're quoting three different things, and none of them are comparable.
One quotes cost per submission. One quotes cost per accepted placement. One quotes cost per link that was live on day one. None of them quote cost per link still live at day 90. That would be honest.
The three cost-per-link numbers you'll see
If a vendor doesn't re-check links after day 1, they're not selling you link-building. They're selling you a disappearing act.
Why vendors hide the 90-day number
A typical vendor might report these numbers on the same campaign:
The vendor quotes the $20 number ('we cost $20 per submission'). The marketing team amplifies it. The sales deck says 'low-cost link building at $20 per attempt.' By the time it reaches the buyer, the number has stuck: '$20 per link.' It's not a lie. It's just not the number that matters.
The 90-day removal rate (40% in this example) is normal for the category. Publishers edit listings, clean up spam, redirect old pages. But it's also invisible. The vendor checked on day 1. The client never heard from them again. The link disappeared on day 60. The client never found out.
How to calculate the number that matters
You need five data points. Most vendors can give you three. If they won't give you the other two, walk away.
Once you have all five, calculate:
**Cost per 90-day link = (Total spend) ÷ (Links still live at day 90)**
Cost per 90-day link is the only number you can defend to a client. Every other number is a vendor marketing metric.
What a healthy cost-per-link number looks like
Industry benchmark varies by publisher type and geography. But here's a rule of thumb:
If a vendor quotes $50 per link at 90-day, they are either: (1) using low-quality publishers you'll regret, (2) not re-checking (so links disappear after day 1 and they don't tell you), or (3) counting labor-free (no humans involved, which means no strategy).
How removal timing breaks the math
Links don't disappear evenly. They disappear in waves. Understanding the curve changes how you bid on campaigns.
If a vendor only checks at day 1, they report 90% success. If they re-check at day 7, it drops to 75%. Day 30 check? 60%. Day 90 check? 40–50%. The removal curve is real. Vendors that skip day 7 re-checks are hiding the truth.
Every link-building platform says they verify links. Ask them when they re-check. If the answer is 'once on day 1', they're not verifying. They're just checking.
What to ask before buying
Before you sign a contract, get these three commitments in writing:
1. **Re-check schedule**: When will links be verified as live? Demand 24h, 7d, 30d, 90d as the baseline. If they won't commit, the platform is not designed for verification. It's designed for throughput.
2. **Removal documentation**: If a link disappears at day 60, will they tell you? And will they re-attempt the placement? Vendors that silently mark links as 'removed' without notification are leaving money on the table and hoping you don't notice.
3. **90-day cost transparency**: Ask them to calculate cost per link still live at day 90 on a reference customer's campaign (with permission). If they balk, they don't know the number.
Any vendor that can't or won't answer all three is selling you hope, not links.