Channel Saturation Estimator
Predict when a channel's rising costs push it past profitability.
Comfortable runway, roughly 7 months before costs cross your ceiling. Use the time to test the next channel before you need it.
Rising CPA compounds, so saturation arrives faster than a linear read suggests. Diversify while a channel is still efficient, not after it breaks.
About this calculator
Every paid channel gets more expensive as you scale it, more competition for the same auction, audience fatigue, diminishing creative novelty, and that CPA inflation compounds every month rather than creeping up linearly. This estimator projects forward from your current inflation rate to tell you how many months you have before the channel crosses the ceiling where it stops making money, so diversification starts before the channel breaks, not after.
How to use it
- Enter your current CPA (cost per acquisition) on the channel.
- Enter the monthly CPA inflation rate, how fast cost per acquisition is rising month over month on this channel.
- Enter your maximum viable CPA, the ceiling above which the channel no longer returns profit.
- Read months to saturation, the projected CPA in six months, and how much headroom is left before you hit the ceiling.
Methodology
Months to saturation is calculated by compounding: since CPA rises geometrically each month (current CPA × (1 + inflation rate)^months), the tool solves for the month where CPA equals your max viable CPA using logarithms: log(max CPA ÷ current CPA) ÷ log(1 + inflation rate).
If your max viable CPA is already at or below current CPA, the channel is treated as already saturated (0 months). If inflation is zero or the max CPA input makes the channel effectively unbounded, saturation is treated as not on the horizon.
Projected CPA in six months is current CPA × (1 + monthly inflation)^6, giving a concrete near-term checkpoint alongside the saturation date.
Because CPA inflation compounds rather than adding linearly, a channel with even a modest monthly inflation rate saturates faster than a straight-line projection would suggest, this is why the model explicitly compounds rather than extrapolating linearly.
FAQ
A channel inflating 6% a month doesn't add a flat dollar amount each month, it multiplies the prior month's CPA. Over 12 months that compounds to roughly double the starting CPA, far more than a linear "6% × 12 months = 72% increase" estimate would suggest, which is why saturation tends to arrive sooner than gut instinct predicts.
It should be the CPA at which the channel stops being profitable given your LTV, gross margin, and payback-period requirements, not just your current comfort level. If you don't have that number, work backward from LTV × gross margin × your target payback fraction to get a defensible ceiling.
Start standing up a second channel now, not when this one crosses the ceiling. Diversification, testing a new channel, building organic or content assets, or shifting toward brand, takes longer to mature than a short runway allows, so the lead time matters more than the exact saturation month.
Yes, CPA inflation isn't always a one-way ratchet. Seasonal auction pressure eases, new ad formats or targeting options can reset efficiency, and creative refreshes can lower costs temporarily. Re-run this regularly with updated inflation data rather than treating one projection as permanent.