Anastasia Nikolaeva

Startup · Financial modeling

Startup financial model: adapt the drivers for apps, SaaS and marketplaces

Build one financial core, then choose the operating drivers that actually create revenue and cash in your business.

Originally published February 2025Updated

Refined the comparison across three business models, added a common model architecture and decision checks, and linked to the detailed examples for each model.

The same statements, different operating engines

A generic financial model can organize assumptions, a P&L, cash flow and a balance sheet. It cannot tell you which behavior actually generates revenue. A mobile app may be driven by active users and in-app events; B2B SaaS by accounts, seats and contract renewals; a marketplace by available supply and completed orders. Start with a shared financial structure, then build the operating layer that fits the product.

Choose the primary forecast unit before choosing a revenue formula
BusinessOperating unitRevenue eventTypical bottleneck
Mobile appActive user or paying subscriberSubscription period, ad impression or purchaseRetention and engagement
B2B SaaSPaying account, seat or usage unitService period or contracted usageQualified pipeline, sales cycle and churn
MarketplaceCompleted order between buyer and sellerFee, subscription or advertising serviceLiquidity, match rate and repeat transactions

1. Build a shared set of financial schedules

Use a monthly timeline with explicit launch dates and a separate assumptions section. Link each product or channel to a revenue schedule and the direct costs it causes. Then add payroll, operating expenses, capital expenditure, financing and working capital. The P&L, cash flow and balance sheet should reconcile; a financing inflow is cash and equity or debt, not customer revenue.

Calculation logic

Operating drivers → earned revenue and direct costs → P&L

Billing, collections and payment timing → cash flow

Assets, liabilities and funding movements → balance sheet

Separate assumptions from formulas, label units and currencies, and keep actual results alongside the forecast once the business is operating. Use a base case and a few targeted stress cases rather than building a single detailed projection that cannot be explained.

2. An app needs user cohorts and more than one revenue path

For an app, distinguish downloads, activated users and monthly active users. Forecast organic and paid acquisition by channel, then carry users through retention cohorts. A person who installed the app once is not necessarily available for advertising or a subscription sale in a later month. Model subscription conversion and churn, in-app purchases, and ad impressions as separate events if the product uses them.

Mobile app model · acquisition inputs

App workbook extract: launch timing and acquisition assumptions. The input values illustrate the model structure and are not current cost-per-install benchmarks.
Calculation logic

Active users = retained previous users + newly activated users

Subscription revenue ≈ eligible paying subscribers × realized monthly price

Ad revenue = monetized impressions ÷ 1,000 × realized net CPM

For subscriptions, distinguish recognized revenue from store payouts and billing cash; include store commissions where applicable. For ads, use impressions actually served and a net rate. An app may have many downloads and still struggle if engagement and monetization per active user are low.

Explore the mobile app financial model and its three monetization methods

3. SaaS needs acquisition channels, contracts and retention

A B2B SaaS model should trace self-service visitors, inbound leads and outbound opportunities into paying accounts without counting the same buyer twice. Account for sales-team capacity and the lag from first contact to contract. Roll paying customers and MRR forward through new business, expansion, contraction and churn.

B2B SaaS model · website inputs

SaaS workbook extract: website and paid acquisition inputs. Its historical values are illustrative assumptions, not channel benchmarks.
Calculation logic

Ending MRR = opening MRR + new MRR + expansion MRR − contraction MRR − churned MRR

Cash receipts = invoices paid during the month, including relevant prepayments

Contracted recurring revenue, revenue earned during the service period and money collected can differ. Analyze acquisition spending and sales salaries with consistent channel attribution, then test how a longer sales cycle and higher churn affect cash runway.

See the detailed B2B SaaS subscription and sales-channel model

4. A marketplace needs supply, demand and completed orders

Forecast sellers and buyers separately. Acquisition on both sides does not guarantee successful matches: active supply, available inventory, repeat visits, matching rate and order completion determine transaction volume. Define GMV before any buyer fees, platform take rate, seller subscription or advertising. Keep pass-through payments separate from platform revenue.

Marketplace model · two-sided acquisition

Marketplace workbook extract: separate buyer and seller acquisition roll-forwards. The 2025 scenario is illustrative; platform liquidity and completed orders still need separate checks.
Calculation logic

Completed orders = demand opportunities × match rate × completion rate

GMV before added buyer fee = completed orders × order value

Transaction-fee revenue = eligible GMV × effective platform take rate

A seller may pay a membership fee even when order volume is low, but fees can also discourage supply. Test the order mix, refunds, payment processing and settlement timing before assuming take rate becomes cash. If buyer and seller growth are out of balance, acquisition spend can grow while transaction volume stalls.

Read the marketplace model and its three revenue streams

5. Add only the complexity the decision needs

Many products cross categories. A marketplace may sell SaaS tools to sellers; an app may include a B2B contract; a SaaS product may charge for usage. Create one customer and revenue logic per stream, then consolidate the results into the shared statements. Do not apply two different acquisition funnels to the same person or count customer prepayments as immediate earned revenue.

Choose the model detail by the decision ahead: price a new channel, compare product strategies, plan hiring or determine the next capital raise. Start with the few drivers that move the answer, test sensitivities and add cohorts or contract schedules as evidence improves. A reusable starting structure is valuable when you can explain how its inputs become cash; tailoring the drivers is what makes it a decision tool.

Make the model fit the way your business works

If your startup combines products or revenue streams, we can build one set of operating drivers and statements that supports your actual decisions.

Discuss your financial model