SEO Campaign ROI Calculator

Formula and inputs

Monthly net profit is attributed organic revenue minus retainer and content costs. ROI compares cumulative profit over the window to the upfront investment. Because revenue arrives late in SEO, the same inputs produce very different ROI at 6, 12, and 18 months; run all three before judging the channel.

Example scenario

Eighteen-month retainer evaluation

A B2B company spends $8,000 on technical fixes and a content foundation, then pays a $3,500 monthly retainer. Averaged over eighteen months, organic attribution reaches $6,000 a month, low early and higher late. They model the full eighteen months.

• -Initial investment: $8,000
• -Monthly revenue: $6,000 (period average)
• -Monthly costs: $3,500
• -Time period: 18 months

Average net profit of $2,500 a month pays the upfront work back a bit past month three on paper, but remember the average hides the shape: real cash recovery lands later because early months underperform the average. The eighteen-month ROI is solidly positive if the steady state holds.

Common mistakes

• -Judging SEO on a window shorter than the time it takes rankings to move.
• -Using a peak-month revenue figure instead of a period average that includes the ramp.
• -Crediting SEO with branded-search revenue that existing customers would have generated anyway.

How to interpret the output

• -If the model is negative at 18 months even with reasonable assumptions, the niche may be too competitive for your budget; consider narrower keyword targets.
• -A positive late-window ROI with painful early cash flow is normal for SEO; check the monthly profit line against your runway.
• -Once steady state is reached, recompute with the retainer as the only cost; ongoing SEO usually shows much stronger maintenance-mode returns.

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