Flat Rate vs Percentage-Based Dunning Tools: Which Is Better for Small SaaS

Flat rate vs percentage-based dunning tools is a decision that will cost you real money if you get it wrong. Most SaaS founders pick a dunning tool based on features and reviews without looking closely at the pricing model. But the pricing model often matters more than the feature list, especially below $30K MRR.

Here's how both models work, what they cost at different revenue levels, and where the crossover point is.

How percentage-based pricing works

Percentage-based dunning tools charge you a cut of the revenue they recover. The typical range is 3-5% of recovered MRR, though some tools go higher. A few charge a percentage of total MRR regardless of what they recover.

The appeal is obvious: if the tool recovers nothing, you pay nothing. Your cost scales directly with the value you get. For a SaaS at $2K MRR that isn't sure failed payments are even a real problem yet, this feels safe.

The math gets less appealing as you grow.

How flat-rate pricing works

Flat-rate dunning tools charge a fixed monthly fee regardless of how much revenue they recover. You might pay $29/month or $79/month, and whether the tool recovers $200 or $2,000 that month, the price stays the same.

The risk here is the opposite: if the tool recovers nothing, you still pay. But for any SaaS with measurable failed payments (which is nearly all of them), the economics tip toward flat-rate quickly.

The math at every MRR level

Let's run the numbers. Industry data shows that roughly 9% of subscription charges fail each month, and a good dunning tool recovers 50-70% of those failures. We'll use 9% failure rate and 60% recovery rate as our baseline.

At $5K MRR: Monthly failed payments: $450. Recovered at 60%: $270. Percentage-based cost (5% of recovered): $13.50/month. Flat-rate cost (e.g., ReviveBy Starter): $29/month.

The percentage model wins here. You're paying about half as much, and the absolute dollar difference ($15.50/month) is small either way. At this scale, neither pricing model will make or break you.

At $10K MRR: Monthly failed payments: $900. Recovered at 60%: $540. Percentage-based cost (5%): $27/month. Flat-rate cost: $29/month.

Nearly identical. This is approximately the crossover point where flat-rate starts matching percentage-based pricing. And the flat-rate tool has no incentive to underperform, since it gets paid regardless.

At $15K MRR: Monthly failed payments: $1,350. Recovered at 60%: $810. Percentage-based cost (5%): $40.50/month. Flat-rate cost: $29/month.

Flat-rate saves you $11.50/month, or $138/year. The gap is widening.

At $20K MRR: Monthly failed payments: $1,800. Recovered at 60%: $1,080. Percentage-based cost (5%): $54/month. Flat-rate cost: $29/month.

Flat-rate saves $25/month, or $300/year. You're now paying nearly double with the percentage model.

At $30K MRR: Monthly failed payments: $2,700. Recovered at 60%: $1,620. Percentage-based cost (5%): $81/month. Flat-rate cost: $29/month (Starter) or $79/month (Growth tier with more features).

Even on the Growth tier, flat-rate is cheaper. On Starter, you're saving $52/month, or $624/year.

At $50K MRR: Monthly failed payments: $4,500. Recovered at 60%: $2,700. Percentage-based cost (5%): $135/month. Flat-rate cost: $29-79/month.

Flat-rate saves $56-106/month. Over a year, that's $672 to $1,272 back in your pocket.

The crossover point

Based on these numbers, the crossover happens around $8K-$10K MRR. Below that, percentage-based pricing costs less in absolute dollars. Above that, flat-rate wins, and the gap grows linearly with your revenue.

Here's the thing most founders miss: if you're below $8K MRR, the total dollar difference between the two models is under $20/month. That's not enough to drive a decision. What should drive the decision is which tool actually recovers more payments.

Above $10K MRR, the pricing model becomes a meaningful cost factor. And it only gets more meaningful as you grow.

The hidden cost of percentage-based pricing

Beyond the raw math, there's a structural problem with percentage-based pricing that's worth thinking about.

A percentage-based tool has a financial incentive to recover your payments. That sounds good. But it also has a financial incentive to claim credit for recoveries that would have happened anyway. Stripe's built-in Smart Retries already recover a portion of failed payments automatically. If a dunning tool sends an email on day 1 and Stripe's retry succeeds on day 2, who gets credit?

With percentage-based pricing, the tool has every reason to count that as their recovery. With flat-rate pricing, there's no attribution game. You pay the same amount regardless, and you can evaluate the tool purely on whether your overall recovery rate improves.

There's also the growth penalty. As your SaaS grows (which is the whole point), your dunning costs grow proportionally with percentage-based pricing. A flat-rate tool costs the same at $50K MRR as it does at $10K MRR. Your effective cost per dollar recovered drops every month.

When percentage-based actually makes sense

To be fair, percentage-based pricing isn't always worse.

Pre-product-market-fit: If you're under $5K MRR and still figuring out whether your SaaS will survive, minimizing fixed costs is rational. A percentage-based tool that costs $10-15/month is one less thing to worry about.

High failure rates in specific niches: Some industries (consumer subscriptions with prepaid cards, international customers with higher decline rates) see failure rates well above 9%. If your failure rate is 15-20%, the dollar amounts shift. But the crossover point still exists; it just moves slightly higher.

Short-term usage: If you're planning to build your own dunning system eventually and just need something for 3-6 months, the lower cost at small scale could save you a few hundred dollars total.

For most SaaS companies that have found product-market fit and are growing past $10K MRR, flat-rate pricing is the better long-term bet.

What this means for tool selection

When evaluating dunning tools, check the pricing model first. Here's a quick framework:

If you're under $5K MRR, pick the tool with the best recovery rate regardless of pricing model. The absolute cost difference is negligible. Focus on whether it actually works.

If you're between $5K and $15K MRR, you're in the transition zone. Either model is fine, but lean toward flat-rate if you expect to grow. You'll save money within a few months.

If you're above $15K MRR, flat-rate pricing is almost certainly cheaper. At this point, evaluate flat-rate tools on features and recovery performance, not price. The cost is low enough that feature differences matter more.

ReviveBy uses flat-rate pricing at $29/month (Starter) and $79/month (Growth) with no percentage of recovered revenue. Other tools in the flat-rate category include ChurnWard. On the percentage-based side, some enterprise tools still use this model, though many have shifted to MRR-scaled subscription pricing, which has its own scaling problem.

The bottom line: every dollar your dunning tool takes as a percentage fee is a dollar that could be compounding back into your business. Once you're past the very early stage, flat-rate pricing aligns the tool's cost with your growth instead of working against it.