A Google ad costs $4 and disappears. A resolved Reddit thread costs $0 and lives forever.
Most marketing teams know intuitively that being good on Reddit is good for the business. Most cannot defend it in a CAC discussion against a CFO who wants to see the numbers.
This post is the back-of-envelope CAC math, with the assumptions called out so you can argue with them.
The two channels we are comparing
Channel A: paid acquisition (Google ads as the canonical example). You pay per click. Some clicks convert. The CAC is cost-per-click divided by conversion rate.
Channel B: organic Reddit, run well. You pay nothing per click. You pay a fixed cost for the team running the Reddit operation. Some Reddit threads end up with your brand looking good and produce traffic.
The Google math
For most B2C SaaS companies, the rough numbers as of early 2026 are:
- Cost per click: $3-$8 depending on category
- Click-through rate: ~3-5%
- Landing-to-trial rate: ~5-15%
- Trial-to-paid rate: ~15-30%
- Final CAC: $40-$200 per paying customer
This varies wildly by category, but the point is: paid CAC is in the high tens to low hundreds of dollars per acquired customer, paid every time.
Critically, every dollar you stop spending on Google ads, you stop acquiring customers from. The channel turns off the moment you stop paying.
The Reddit math
The Reddit math is harder to compute and underestimated as a result.
Step 1: figure out the operational cost. A single named human, two hours a day, five days a week, for a quarter, is roughly:
- 0.25 FTE community manager: ~$25,000/quarter loaded
- Tooling: Subportly or comparable, $2,500/quarter
- Total: ~$27,500/quarter
Step 2: figure out the outputs. In a quarter, a well-run Reddit shift produces something like:
- 800-1,200 resolved DMs (60% support, 40% sales adjacent)
- 50-150 substantive thread replies that end up cited later
- 5-15 “complaint becomes public win” threads
- 2-5 partnership / AMA opportunities
- A modmail relationship with 20-40 subreddit mods
Step 3: figure out the conversion math. This is where it gets fun.
Of those 50-150 thread replies, maybe half end up Google-indexed and ranking for queries like “$your_brand vs $competitor” or “$your_brand alternative” or “is $your_brand worth it.” Each ranking thread produces ongoing traffic, for years.
A single reasonable Reddit thread that ranks for “$your_brand alternative” can produce 50-200 pageviews a month indefinitely. If 5% of those pageviews convert into a trial signup, and 20% of trials convert into paid, that’s roughly 0.5-2 paid customers per month per ranking thread, indefinitely.
Multiply by the 25-75 ranking threads you accumulate over a quarter. Assume each lasts 2 years before getting buried by newer content.
Step 4: do the CAC math. Reddit operational cost over 8 quarters: ~$220,000. Customer acquisition over the same 8 quarters from accumulated ranking threads: anywhere from 800 to 6,000 paying customers depending on the conversion math, rate of accumulation, and category.
That’s a CAC of $35-$275, with most companies landing somewhere in the $50-$120 range. That’s competitive with Google. Sometimes much better.
What this math hides
The first-order CAC comparison undersells Reddit by ignoring two things.
Reddit threads compound. A thread you replied to two years ago is still working today. Google ads stop working the moment you stop paying.
The brand-perception lift. Customers who arrive via Reddit tend to be more sophisticated, lower-churn, higher-LTV than customers from paid ads. They often arrive after reading 3-5 Reddit threads and concluding your brand is the right answer for them. Those customers are pre-sold. They convert higher and stick around longer.
We have seen the LTV difference be as much as 2x for Reddit-acquired customers vs paid-acquired customers in the same B2C SaaS category. That is not a small number.
What this math overstates
To be fair, the Reddit math has weaknesses too.
Attribution is fuzzy. Most companies cannot cleanly attribute a customer to “found us via a Reddit thread two years ago.” So the numbers are underestimated or overestimated, depending on how you squint. Honest answer: the impact is real, but the precision is bad.
It takes time. The Reddit operation produces nothing in month one. Maybe a little in month three. Real returns kick in around month nine or twelve. If your CFO is on a quarterly cycle and Reddit doesn’t produce returns this quarter, the spend looks bad.
It can be done badly. A bad Reddit operation produces zero ranking threads. The math above assumes a competent operation. If your team is not actually doing the work well, the math goes to zero.
The strategic question
The CAC math is the part that gets you in the door of the CFO conversation. The strategic question is bigger.
Paid acquisition is a tax you pay every quarter. Reddit done right is an asset you build that compounds.
For most B2C SaaS companies, the right answer is to do both. Run paid acquisition for the predictable quarter-over-quarter inflows. Build a Reddit operation in parallel for the long-term, lower-CAC, higher-LTV channel that you accumulate as an asset.
The companies that get this wrong are the ones that put 100% of the marketing budget into paid, forever. Those companies are renters. The companies that build owned channels are the ones still around in 5 years.
Reddit, done right, is one of the best owned channels available to B2C software companies in 2026. Treat the operational cost like CapEx, not OpEx, and the math gets clearer.
Where to start
If your team is currently spending nothing on Reddit and a lot on paid: shift 5% of the paid budget into a small, named, two-hour-a-day Reddit operation for one quarter. Measure what happens in quarters two and three. You will not see the full picture for a year, but the early signals will tell you whether to keep going.
The early signals to watch: how many Reddit threads index in Google for queries about your brand, how many of those threads have your brand-account participation, and what your “Reddit referral” traffic looks like in analytics six months in.
These will not be Google-ad-sized numbers. They will be something more interesting: numbers that are still going up when you check them next year.
Subportly makes the operation that produces this CAC math possible, with one inbox across every account, in under 10 hours of community-manager time per week. See how it works.