Find the month organic overtakes paid
Both channels, month by month, over the horizon you choose. The useful answer is not which one wins. It is when the lines cross, and whether your runway reaches that month.
Ads win every month until month eleven, and lose every month after. Which one is right depends entirely on whether you need pipeline this quarter or an asset next year.
Why this tool exists
The SEO-versus-paid argument gets had in almost every marketing team, and it is almost always had badly, as a debate about which channel is better in the abstract, decided by whoever is more senior or more persuasive rather than by any number either side can point to.
Comparing the two on a single month's performance guarantees paid wins, because paid produces traffic in week one and SEO does not. Comparing lifetime value guarantees SEO wins, because organic traffic persists and paid traffic stops the day the card is declined. Both comparisons are true and neither is useful, because the horizon chosen determines the answer before any data is examined.
This simulator runs both channels month by month across a horizon you set, with CPC inflation on the paid side and a ramp curve plus a decay assumption on the organic side. It reports the crossover month, the cumulative position at your horizon, and a recommended blended split, because in practice the answer is almost never one channel.
- The exact month cumulative organic profit overtakes cumulative paid profit
- Total cost, customers won and cost per customer for each channel across the horizon
- What happens to each channel's traffic the month you stop paying
- A recommended budget split, sized from measured efficiency and corrected for your horizon
- An exportable month-by-month model for the budget conversation
Who it's for
Anyone deciding where the next increment of budget goes.
Need to defend a channel split with a model rather than a preference.
Need to know whether the runway reaches the crossover month.
Need to show what rising CPCs do to a paid-only strategy over three years.
Need to make the compounding case in the language of payback periods.
Need cumulative cash positions, not channel advocacy.
Need to recommend a split a client will actually believe.
Need to model shopping ads against category-page organic.
Need to escape an auction where CPCs rise faster than conversion rates.
How it works
Set the horizon, describe both channels, read the crossover.
Six to sixty months, and this choice moves the answer more than any other
Budget, CPC, conversion rates, CPC inflation and management fee
Investment, current and mature traffic, ramp length and decay if you stop
Cumulative curves, head-to-head totals, and a recommended split
Six to sixty months, and this choice moves the answer more than any other
Budget, CPC, conversion rates, CPC inflation and management fee
Investment, current and mature traffic, ramp length and decay if you stop
Cumulative curves, head-to-head totals, and a recommended split
Features
Every assumption that decides this argument, made explicit.
Month-by-month cumulative curves
Both channels plotted against a zero line, with the crossover marked. The picture ends the argument faster than the table does.
CPC inflation
Auction prices rise as competitors enter. Modelling a flat CPC across three years is the most common error in this comparison.
The stop test
Shows what each channel delivers the month after you stop paying. Paid goes to zero; organic decays. That difference is the whole argument.
S-curve ramp
Organic traffic modelled as slow, then steep, then flattening, with continued compounding after maturity.
Recommended blended split
Re-simulates both channels at the recommended budget split, with diminishing returns applied to the organic side.
Month-by-month export
Every month of both channels as CSV, ready for a finance model.
What you'll get
The numbers that settle the decision.
When cumulative organic profit passes cumulative paid profit.
Where each channel leaves you in cash terms at the end of the window.
True CAC for each channel across the full period, not a single month.
ROAS and ROI for both, calculated on gross profit.
A percentage allocation with the reasoning behind it.
What organic keeps delivering after the investment stops.
See it in action
PreviewThe simulator is live at the top of this page with a worked B2B example loaded.
Ads win every month until month eleven, and lose every month after. Which one is right depends entirely on whether you need pipeline this quarter or an asset next year.
Why it settles the argument
Once everyone can see that the answer changes at 12 months versus 36, the debate becomes a question about the business rather than about the channels.
Nine percent annual CPC inflation compounds into a very different three-year picture. Most paid-only plans have never modelled it.
The recommendation is a percentage allocation, because funding one channel to zero is almost never the right answer.
Both sides enter their own assumptions. The model does the arithmetic, which is harder to argue with than a point of view.
Use cases
Where this simulation changes a decision.
Eighteen months of runway and one shot at picking correctly.
Set the horizon to match the runway and compare crossover against it.
A clear answer on whether the organic asset arrives before the money runs out, and a defensible split if it does not.
Spend rising every year while customer volume stays flat.
Model realistic CPC inflation over 36 months against an SEO programme.
A picture of where paid-only leads that makes the case for the organic investment obvious.
Client wants a single recommendation and distrusts the one that favours the agency's strengths.
Build the model with the client's own numbers and share the scenario link.
A recommendation the client can re-run themselves, which is why they accept it.
Twelve months into a programme, tempted to move the budget to paid for a faster quarter.
Set the decay retention slider to model what happens to organic traffic if you stop.
A concrete figure for the traffic being abandoned, which is usually higher than expected.
How the simulation works
Paid search is modelled straightforwardly: budget divided by CPC gives clicks, clicks flow through your conversion and close rates to customers, and CPC inflates annually at the rate you set. Management fees are added on top of media, because they are a real cost that comparisons routinely omit.
Organic is modelled as a logistic ramp from today's traffic to a maturity level you specify, over a ramp period you set. After maturity, continued investment keeps compounding at a modest rate, capped because content programmes do not grow forever. The decay retention slider then answers the question that actually distinguishes the two channels: what arrives next month if you stop paying entirely.
The recommended split is not a weighted average of the two results. It re-runs both simulations at the proposed budget allocation, with organic scaled sublinearly to reflect diminishing returns on content and links, so the blended figure is a real result rather than an interpolation between two other scenarios.
Any comparison of these channels is really a statement about time. This tool makes that choice visible instead of burying it in an assumption.
Management fees on paid, ramp cost on organic. Comparisons that omit either produce the answer the omitter wanted.
The stop test is the clearest expression of the difference. One channel leaves you with an asset; the other leaves you with a receipt.
Frequently asked questions
Related resources
The wider decision this simulation sits inside.
Settle it with a model, not a meeting
Enter both sides' assumptions and let the arithmetic decide. It takes about ten minutes and usually ends a debate that has been running for months.