# Marginal Revenue for SaaS: Why the Next Customer Is Almost Pure Profit > Marginal revenue explained for SaaS founders. Formula, why SaaS marginal cost is near zero, and pricing implications when one more customer costs you almost nothing. - **Author**: Ayush Agarwal - **Published**: 2026-06-07 - **Category**: SaaS Finance, Pricing, Economics - **URL**: https://dodopayments.com/blogs/marginal-revenue-saas-explained --- Marginal revenue is the additional revenue earned from selling one more unit of a product. In a traditional manufacturing business, the next unit also costs you raw materials, labor, and shipping, so marginal revenue and marginal cost both matter. In SaaS, the next unit of "the product" is effectively a software license issued from the same codebase, running on infrastructure that scales sub-linearly. Marginal cost is close to zero, which makes marginal revenue do unusual things in pricing strategy. This guide explains the marginal revenue formula, why SaaS economics invert the textbook interpretation, and what it means for how you should think about pricing, discounting, and tier design. ## The marginal revenue formula $$ \text{Marginal Revenue} = \frac{\Delta \text{Total Revenue}}{\Delta \text{Quantity Sold}} $$ In plain language: take the change in revenue, divide by the change in units sold. If you go from selling 100 subscriptions to 101 subscriptions and revenue goes from $5,000 to $5,049, marginal revenue is $49. In a single-price SaaS, marginal revenue is just the price of the subscription, because every new customer pays the same fee. Selling the 101st customer brings in the same $49 (or whatever the price is) as the 100th. In a multi-tier or volume-discounted SaaS, marginal revenue declines as quantity grows. The 100th seat of a 100-seat contract is often discounted compared to the 10th seat of a 10-seat contract. ## Why SaaS marginal cost is near zero In manufacturing, every additional widget consumes raw materials, machine time, and shipping. Marginal cost is meaningful. In SaaS, the same codebase serves customer number 1 and customer number 10,000. Infrastructure scales but typically sub-linearly. The cost to serve a new customer is: - Some incremental compute and storage (often cents per month) - Some incremental support load (depends on product complexity) - Payment processing fees (3% to 4% of the transaction value) - Customer success effort for higher-touch tiers For a self-serve SaaS at $50/month, the incremental cost of one more customer might be $5 to $10. That means the marginal contribution (marginal revenue minus marginal cost) is 80%+ of the subscription price. > If your marginal cost is 10% of marginal revenue, you can afford to underprice the second tier of customers significantly. Every dollar of marginal revenue above marginal cost is contribution toward fixed cost and profit. That asymmetry is the whole reason SaaS multiples exist. > > \- Ayush Agarwal, Co-founder & CPTO at Dodo Payments ## Pricing implications The combination of meaningful marginal revenue and near-zero marginal cost reshapes pricing strategy: ### 1. Volume discounts make sense even at steep rates A customer asking for 50% off at 100 seats is still profitable if the marginal cost per seat is single-digit dollars. Refusing the discount loses 100% of the revenue. Accepting it captures 50% of revenue against near-zero incremental cost. Volume discounts are a margin question, not a cost question. ### 2. Annual discounts are a financing decision, not a margin decision Offering 15% off for annual upfront billing in exchange for 12 months of cash today is a financing trade. The marginal cost saved by collecting upfront is roughly zero. The 15% discount is the cost of capital. If the cash improves working capital meaningfully, the trade is usually worth it. ### 3. Trial economics are about acquisition cost, not delivery cost A 14-day trial costs almost nothing to deliver. The question is not "can we afford the trial" but "does the trial convert enough users to justify the acquisition spend." Marginal delivery cost barely shows up in the equation. ### 4. Usage-based pricing aligns marginal revenue with marginal value In a usage-based model, marginal revenue increases as the customer uses the product more. If marginal cost stays near zero (most software is highly leveraged), every additional usage event is mostly contribution margin. This is why [usage-based billing](https://dodopayments.com/blogs/best-billing-platform-usage-based-pricing) tends to produce higher net dollar retention than flat-tier billing. ## Marginal revenue vs average revenue per user (ARPU) These are not the same: - **ARPU** is total revenue divided by total active customers - **Marginal revenue** is the revenue from the next customer (or unit) For a single-price SaaS, they are equal because every customer pays the same. For a tiered SaaS, ARPU is the blended average across tiers, but marginal revenue depends on which tier the next customer joins. A founder thinking about "the next 100 customers" should use marginal revenue, not ARPU. ## When marginal revenue declines Marginal revenue declines for two main reasons in SaaS: ### 1. Price discrimination via tiers Lower-tier plans capture customers who would not pay the higher price. The 5th customer might pay $200/month for the Pro plan. The 6th customer might be price-sensitive and pay $50/month for the Starter plan. Marginal revenue falls from $200 to $50 even though both are profitable. ### 2. Volume discount curves Enterprise contracts often have stepped pricing: $100/seat for the first 50, $80/seat for the next 100, $60/seat for the next 200. Marginal revenue per seat declines as the contract grows. In both cases, the strategy is valid as long as marginal revenue stays comfortably above marginal cost. The math breaks if you discount past the point where the incremental contribution turns negative (rare in SaaS, but possible at very aggressive enterprise discounts plus heavy support overhead). ## Marginal revenue and payment processing Payment processing is one of the few SaaS costs that scales linearly with revenue. If your effective processing rate is 4%, every $100 of marginal revenue carries $4 of marginal cost. For high-volume SaaS, this is the single largest variable cost line. A merchant of record platform like [Dodo Payments](https://dodopayments.com) charges 4% + 40c on the Standard Plan (with documented add-ons for international cards, subscriptions, and BNPL). For a global SaaS where the alternative is paying for a PSP plus a tax service plus chargeback management separately, the MoR fee is often cheaper all-in. The marginal cost stays close to the headline rate because tax, compliance, and chargeback handling are bundled. ## Diminishing marginal returns at scale Even SaaS hits the wall eventually. Marginal returns start to diminish when: - The next customer requires custom development or integrations - Sales cycles lengthen as you move upmarket - Support load grows non-linearly for complex enterprise customers - Compliance and security review burden grows per deal This is why mid-market and enterprise SaaS have wildly different unit economics than self-serve SMB SaaS. The marginal revenue from a $100K enterprise deal is large, but so is the marginal cost (sales rep commission, solutions engineering time, security review, custom legal). ## How to use marginal revenue in practice Three concrete applications: ### 1. Set discount limits Compute your effective marginal cost per customer (mostly processing fee + minimal support). Set a hard floor on discounting such that marginal revenue stays at least 4x marginal cost. For most SaaS, this means discounts up to 50% to 70% off list are economically rational. ### 2. Decide which features to give away in lower tiers Features with zero marginal delivery cost can be moved down-tier to drive adoption. Features with real marginal cost (high-bandwidth integrations, dedicated support) should stay in higher tiers where marginal revenue covers the marginal cost. ### 3. Evaluate enterprise deals For each enterprise opportunity, ask: what is the marginal revenue (contract value), what is the marginal cost (sales effort, custom work, ongoing support), and what is the contribution margin. If contribution is less than 20% of contract value, the deal is probably a poor fit even if it grows ARR. ## FAQ ### What is marginal revenue in simple terms? Marginal revenue is how much extra revenue you earn from selling one more unit of your product. In SaaS, it is usually the price the next customer pays, minus any volume discount applied at that point in your pricing curve. ### Why does marginal revenue matter for SaaS pricing? Because SaaS marginal cost is near zero, almost all marginal revenue is contribution margin. That changes how you should think about discounts, trials, and tier design. You can afford to discount aggressively as long as marginal revenue stays meaningfully above marginal cost. ### What is the difference between marginal revenue and ARPU? ARPU is the blended average revenue per user across your entire customer base. Marginal revenue is the revenue from the next specific customer. They are equal only in single-price SaaS. In tiered or usage-based pricing, they diverge. ### How does payment processing affect marginal revenue? Payment processing is one of the few SaaS costs that scales linearly with revenue. A 4% effective rate means 4% of marginal revenue is consumed by processing. This is why all-in payment platform economics (rate plus tax plus compliance) matter more than headline rate alone. ### When does marginal revenue stop being useful as a guide? When the next customer requires meaningful incremental cost (custom development, dedicated support, complex compliance review). At that point, you have to look at contribution margin per customer rather than marginal revenue alone. ## Conclusion Marginal revenue is one of the most underused concepts in SaaS pricing. The near-zero marginal cost profile of software makes it possible to discount, give away features, and offer trials in ways that would be uneconomical in any other industry. Founders who think clearly in marginal terms tend to grow faster and stress less about pricing experiments. For SaaS where payment processing is the dominant variable cost, [Dodo Payments](https://dodopayments.com) bundles payment, tax, and compliance into a single MoR fee. See [pricing](https://dodopayments.com/pricing) for the breakdown. --- - [More SaaS Finance articles](https://dodopayments.com/blogs/category/saas-finance) - [All articles](https://dodopayments.com/blogs)