Should You Switch to Usage-Based Billing? Calculate Your ROI First
Bas de Goei
Planning finances for a subscription business is different from traditional business planning. You need the framework of SaaS modeling to handle recurring revenue, customer churn, and long-term growth.
SaaS modeling is financial modeling purpose-built for subscriptions. In practice, SaaS financial modeling forecasts revenue, costs, and cash. They do so using inputs like MRR, ARR, churn, and expansion.
The goal is clarity. You create a single model that ties projections, pricing, and operations into actions.
Why SaaS modeling matters: Recurring revenue behaves differently from one-time sales. Churn and retention shape customer lifetime value (LTV) and drive hiring, spend, and cash runway.
Note: For a deeper primer, see our guide to the SaaS financial model.
Here’s a step-by-step explaining how to build a SaaS financial model:
Note: Read our explanatory guide for a walkthrough on SaaS revenue projections.
A solid SaaS financial model integrates many key metrics that are key to a firm's trajectory. These metrics interact with each other and provide a view of the company's health. Here’s a summary of these vital components:
These metrics are interconnected. For example, a high churn rate negatively impacts LTV. It makes it necessary to either reduce CAC or increase ARPU to maintain a healthy LTV to CAC ratio.
Note: Brush up on SaaS metrics that feed these calculations.
Below are some common SaaS revenue models.
A flat-rate revenue model offers a single, fixed price for all features of the software. All customers pay the same amount, regardless of usage or the specific features they use.
The tiered revenue model offers many pricing packages with other features and usage limits at varying price points. This allows customers to choose a plan that best fits their needs and budget.
In a per-user revenue model, pricing is based on the number of users who can access the software. Each user pays a set fee per month.
The usage-based revenue model charges users based on their usage of the software's features. Examples include the number of transactions, data processed, or API calls made.
A hybrid revenue model combines elements of two or more of the other models. For example, a company might offer tiered pricing with usage-based add-ons or a flat-rate plan with per-user fees for extra features.
Costs influence strategic decisions on pricing, customer acquisition, and business growth. Here's a breakdown of typical SaaS operating costs.
Several typical missteps can undermine the accuracy of SaaS modeling and lead to flawed business decisions.
Many SaaS businesses in their early stages misjudge the rate at which users will churn. This leads to overly optimistic revenue projections.
Solution: Use churn tracking and analysis. Segment churn by customer type and reason to identify patterns. Incorporate churn rates based on historical data and industry benchmarks into your SaaS modeling. Regularly review and adjust churn assumptions.
Another mistake is overestimating how many new users can join within a specific timeframe. The issue often stems from unrealistic marketing or sales effectiveness assumptions.
Solution: Base acquisition forecasts on historical conversion rates from different marketing channels. Conduct thorough market research and factor in seasonality and competitive pressures.
Failing to model the effects of different pricing strategies or potential price changes can lead to forecast issues.
Solution: Conduct a price sensitivity analysis and model different pricing scenarios. Understand the relationship between price, value proposition, and customer willingness to pay. Review and adjust pricing based on market feedback and competitive dynamics.
SaaS revenue isn't just driven by new customer acquisition. Existing customers can upgrade their plans or downgrade/reduce usage. Ignoring these dynamics skews revenue forecasts.
Solution: Track and analyze historical expansion and contraction rates. Model these trends based on customer cohorts, product adoption, and customer success initiatives.
Focusing on top-line revenue growth can be a problem. Failing to consider the cost of acquisition and the time it takes to recoup that cost can lead to unsustainable growth. A long payback period can strain cash flow.
Solution: Calculate and track the CAC payback period. Set targets for payback based on your business model and funding. Analyze the impact of different acquisition channels and user segments on payback.
Note: For a deeper dive into revenue forecasting structure, start here.
Testing new pricing strategies is vital for SaaS businesses to improve revenue, customer acquisition, and retention. SaaS modeling should incorporate the ability to simulate and analyze the impact of these experiments. Let’s zoom in on some experiments to run.
When testing new pricing, isolate one variable at a time, such as the price point of a specific tier or the inclusion of a new feature in a plan. This isolation allows for clear attribution of any changes in key metrics.
Track changes in ARPU, churn rate, and LTV closely during and after a pricing experiment. An increase in ARPU with a minimal rise in churn suggests a successful price adjustment. A marked drop in LTV due to increased churn might indicate a problematic pricing change.
Maintaining version control of your pricing logic within your SaaS financial models is crucial. Doing so allows you to revert to previous pricing structures if an experiment yields negative results and to compare the performance of different pricing iterations over time.
Orb, the done-for-you billing platform, offers valuable capabilities for managing pricing experiments. Its plan versioning feature allows you to create and track different pricing iterations without the messiness and manual work that spreadsheets require.
Orb Simulations enables you to simulate the impact of pricing changes using historical data. This helps you predict how these changes might affect key metrics like ARPU, churn, and LTV before changes are rolled out to customers, and reduces the risk of pricing experiments.
While spreadsheets are often the starting point for SaaS modeling, they present significant limitations as a business grows and its pricing becomes more complex. Here are some signals you should pay attention to.
Spreadsheet-based models are often error-prone due to manual data entry and formula management. Collaboration can be challenging, with multiple versions and difficulties in tracking changes.
Plus, forecasts in spreadsheets tend to be static, lacking the real-time data integration needed for accurate analysis of dynamic pricing experiments.
Once pricing complexity increases (e.g., multiple tiers, usage-based components, frequent experimentation) or the scale of customer data grows, it becomes vital to upgrade to purpose-built infrastructure.
Platforms like Orb provide a scalable solution for managing pricing, billing, and revenue data. Orb ingests raw event data and decouples it from pricing metrics, which allows for easy experimentation and accurate billing.
Moving to a system like Orb offers several advantages over spreadsheets. It reduces the risk of errors through automated data ingestion and calculation, version control, and audit trails.
Orb also enables dynamic analysis by providing real-time usage data, allowing for more accurate forecasting of pricing experiments and their impact on key SaaS metrics.
Key takeaway: The transition from spreadsheets to a dedicated system supports agility, accuracy, and extensibility in your monetization strategy, ultimately driving faster growth.
You forecast MRR/ARR using separate lines for new, expansion, contraction, and churn, then translate ARR to revenue with timing rules. Tie assumptions to funnels, cohorts, and pricing plans.
Pricing shifts change ARPU and churn, which cascade into ARR, LTV, and payback. Model ranges, test, then lock the winner.
Pick a clear metric (events, data, API calls). Model historical usage per account, apply unit rates or tiers, and stress-test high-usage cohorts for SaaS revenue forecast sensitivity.
Connect your billing platform so your model pulls actual invoices, statuses, and usage each month. You’ll reconcile faster and adjust assumptions sooner.
Orb is a done-for-you billing platform that helps you move beyond static billing and gain the insights needed to put your SaaS modeling plans into action. Here's how Orb helps you execute your SaaS modeling:
Ready to transform your billing execution into a strategic asset for growth, bringing your SaaS modeling plans to life? Explore our flexible pricing tiers for a solution tailored to your needs.
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