Financial Model Templates — SaaS, Marketplace, E‑commerce, etc.

Driver‑based models you can trust, with Beancount/Fava hooks for live actuals.

Building a financial model that actually works requires more than just projecting "10% month-over-month growth." The best models are driver-based, grounded in unit economics, and continuously validated against real accounting data. This guide provides battle-tested templates for the most common business models, each designed to integrate seamlessly with Beancount ledgers for live actuals tracking.

What you'll get​

• Three plug‑and‑play templates: SaaS, Marketplace, E‑commerce (plus notes for Usage‑based/API and Fintech).
• A standard "Actuals ⇄ Plan" spine: Inputs → Hiring & Spend → Revenue drivers → P&L / BS / CF → Metrics dashboard.
• Ledger‑first: Pull revenue, COGS, cash, and inventory from Beancount via BQL and visualize with Fava—your ledger remains the system of record.

The key insight is that your financial model should be a living document that reconciles with your books monthly, not a static spreadsheet that diverges from reality within weeks of creation.

How to use these templates (fast path)​

1. Copy the model. Keep everything in one workbook: Assumptions, Headcount, Units & Pricing, P&L, Balance Sheet, Cash Flow, Metrics.

2. Wire your ledger. Export monthly actuals from Beancount/Fava and paste into the Actuals sheet. BQL is SQL‑like; Fava charts and tables are built to work off BQL results.

3. Model forward with drivers. Forecast by units × price × conversion × retention, not by "grow 10% MoM."

4. Scenario switches. Add toggles for Base/Bear/Bull on: acquisition, conversion, ARPU/AOV, churn/returns, gross margin, hiring speed.

5. Check the scoreboard every month; your plan should reconcile to actuals and cash.

The magic happens when you stop guessing and start measuring. Every assumption becomes testable when you have clean actuals flowing in from your ledger.

The common scoreboard (copy these formulas)​

Use these consistently across templates; investors know them.

NRR (Net Revenue Retention):​

NRR = (Start Recurring Rev − Churn − Contraction + Expansion) / Start Recurring Rev

Also known as NDR (Net Dollar Retention). Values >100% mean existing customers grow your book. This is the single most important metric for subscription businesses—it tells you whether your product creates increasing value over time.

SaaS Quick Ratio (growth vs. churn):​

Quick Ratio = (New + Expansion) / (Churn + Contraction)

Popularized by Mamoon Hamid at Social Capital. A ratio >4× is often cited as excellent in early growth stages. This ratio immediately reveals whether you're growing faster than you're shrinking.

Magic Number (sales efficiency, GAAP‑based):​

MN = ((Revenue_t − Revenue_{t-1}) × 4) / S&M_{t-1}

Quarterly measurement; ≈1.0 is healthy. This methodology comes from Scale Venture Partners and measures how much incremental recurring revenue you generate per dollar of sales and marketing spend.

Rule of 40 / Rule of X (growth + profitability):​

(Revenue Growth %) + (Margin %) ≥ 40%

Bessemer's "Rule of X" weights growth more heavily for efficient growers. This framework helps balance growth investment with profitability—critical for sustainable scaling.

Burn Multiple (capital efficiency):​

Burn Multiple = Net Burn / Net New ARR

Lower is better. Popularized by Craft Ventures, this metric shows how much cash you burn to generate each dollar of new recurring revenue. Essential for capital-efficient growth.

E‑commerce MER (Marketing Efficiency Ratio / Blended ROAS):​

MER = Total Revenue / Total Marketing Spend

This provides a whole‑business view versus channel-specific ROAS. MER gives you the true blended efficiency of your marketing efforts across all channels and timeframes.

Inventory fundamentals (E‑com):​

Inventory Turnover = COGS / Avg Inventory
DIO = (Avg Inventory / COGS) × 365

Core working‑capital levers. Higher turnover (lower DIO) means you're converting inventory to cash faster, improving your cash conversion cycle.

Template 1 — SaaS (Subscription)​

Drivers​

Bookings → Billings → Revenue: Model new logos, seating/usage assumptions, and start dates. Handle revenue recognition by contract term—annual deals create deferred revenue that gets recognized monthly.

Retention & Expansion: Track monthly churn %, contraction, and expansion (upsell/cross‑sell) to calculate NRR. Don't hide logo churn behind gross revenue retention—both matter.

Pricing & Discounts: Start with list price, apply effective ARPU calculations, and model your discount ladder. Enterprise deals often have 20-40% discounts that compound over time.

COGS: Include hosting costs, support costs, and third‑party APIs. Track gross margin as Revenue – COGS. Many SaaS companies underestimate support costs as they scale.

S&M engine: Model the full funnel from leads → MQL → SQL → closed-won. Include rep ramp profiles and partner channel contributions.

Outputs​

• MRR/ARR waterfall showing new, expansion, and churn components
• GAAP revenue vs. cash with deferred revenue dynamics
• Key metrics: Gross margin, Magic Number, CAC payback proxy, NRR and Quick Ratio

The waterfall visualization is crucial—it immediately shows whether growth is coming from new customers or existing customer expansion, and how much churn is eating into your growth.

Beancount wiring (examples)​

Recognized revenue by month (positive values):

SELECT YEAR(date) AS y, MONTH(date) AS m,
       -COST(SUM(position)) AS revenue
WHERE account ~ '^Income:Subscriptions'
GROUP BY y, m ORDER BY y, m;

Note: Income accounts are negative in double-entry bookkeeping; multiply by -1 to chart revenue.

COGS (hosting/support) by month:

SELECT YEAR(date) AS y, MONTH(date) AS m,
       -COST(SUM(position)) AS cogs
WHERE account ~ '^Expenses:COGS'
GROUP BY y, m ORDER BY y, m;

Cash balance trend (for runway): Use Fava's balances and charts; export to CSV and join to your plan.

Metrics to watch​

• NRR / GRR (≥100%/≥90% targets vary by segment)
• Magic Number (quarterly, lagged)
• Rule of 40 / Rule of X for efficiency framing
• CAC Payback period (typically 12-18 months for healthy SaaS)

For benchmarking, OpenView publishes excellent SaaS metrics surveys that provide industry standards by company size and segment.

Template 2 — Marketplace (B2B/B2C two‑sided)​

Drivers​

Demand side: Active buyers × orders per buyer × conversion rate × AOV. Model seasonality and cohort behavior—early marketplace users often have different patterns than later adopters.

Supply side: Active sellers × listings × match rate. Track liquidity as the percentage of listings that transact within N days (typically 30 days).

GMV & Take Rate: Revenue = GMV × take rate + ancillary fees (ads, logistics, payments). Most successful marketplaces expand beyond basic transaction fees.

Variable costs: Payment processing, chargebacks, dispute operations, seller incentives. These can be 15-25% of GMV for complex marketplaces.

Operations model: Model escrow/clearing flows (funds in, funds out) and working capital requirements.

Outputs​

• GMV growth and net revenue after take rates
• Contribution margins after variable costs
• CAC by side and payback periods
• Liquidity metrics and concentration risk (top-N buyer/seller share)

The liquidity metrics are what separate successful marketplaces from those that struggle. You need enough supply to satisfy demand and enough demand to make supply profitable.

Beancount wiring (pattern)​

Map pass‑through funds via a clearing/escrow account:

• Assets:Clearing:Escrow captures buyer receipts and seller payouts
• Income:Marketplace:Commissions captures take rate; Income:*:Fees for ancillary revenue

GMV approximation: Sum gross buyer inflows to the clearing account; revenue comes from commission/fees accounts.

Example (monthly marketplace revenue):

SELECT YEAR(date) AS y, MONTH(date) AS m,
       -COST(SUM(position)) AS net_rev
WHERE account ~ '^Income:(Marketplace|Fees)'
GROUP BY y, m ORDER BY y, m;

Then compute GMV from your clearing flows or order system export; reconcile monthly.

Marketplace metrics​

Track the canonical set: GMV, Take Rate, Liquidity/Fill rate, Concentration, and Repeat usage. Andreessen Horowitz's "13 Metrics for Marketplace Companies" remains the definitive guide.

Template 3 — E‑commerce / DTC​

Drivers​

Traffic × Conversion × AOV: Segment by channel (organic, paid, email, social) and device when possible. Mobile conversion rates are typically 1-3% while desktop can be 3-5%.

Returns & Discounts: Model refund rates (typically 15-30% for apparel) and promotional cadence impact on net sales.

COGS & Fulfillment: Include product COGS, freight‑in/out, packaging, pick/pack labor, and payment processing fees.

Marketing spend: Track channel‑level ROAS for optimization, but use MER (blended) for planning since attribution isn't perfect.

Inventory management: Model lead times, reorder points, safety stock, and DIO (Days Inventory Outstanding).

Outputs​

• Net sales after returns and discounts
• Contribution margin after all variable costs
• MER and channel-specific payback periods
• Cash conversion cycle including inventory turns

The inventory component is critical for DTC brands—poor inventory management can kill an otherwise profitable business through stockouts or excess carrying costs.

Beancount wiring (examples)​

Net sales (after refunds/discounts):

SELECT YEAR(date) AS y, MONTH(date) AS m,
       -COST(SUM(position)) AS net_sales
WHERE account ~ '^Income:(Shop|Store|Sales)'
GROUP BY y, m ORDER BY y, m;

COGS & fulfillment (variable):

SELECT YEAR(date) AS y, MONTH(date) AS m,
       -COST(SUM(position)) AS variable_costs
WHERE account ~ '^Expenses:(COGS|Fulfillment|Shipping|PaymentFees)'
GROUP BY y, m ORDER BY y, m;

Inventory balance (period end): Use Fava's balances report for Assets:Inventory:* to compute Average Inventory and DIO.

E‑commerce metrics​

Focus on conversion rate, AOV, customer LTV, CAC, and return rate. Shopify's merchant resources provide excellent benchmarks by industry vertical.

Notes for Usage‑based / API / Infrastructure​

Pricing model: Price per unit (API requests/GB/compute minutes) × usage distribution per account. Track P50/P95 usage growth to understand expansion patterns.

Revenue recognition: Accrue usage monthly, invoice in arrears or advance based on plan structure.

Unit economics: Track COGS per unit (cloud compute/storage/networking) to maintain positive gross margin per unit.

Expansion mechanics: Seed accounts with initial credits; model natural expansion via usage curves rather than forced upsells.

Usage-based models often enhance NRR when properly aligned to customer value creation—customers who get more value naturally use more of your product.

Notes for Fintech / Payments​

Revenue model: TPV (Total Payment Volume) × take rate ± interest spread. Track interchange income and network fees separately.

Risk & reserves: Model fraud/credit losses, chargebacks, and regulatory reserve requirements that impact available cash.

Unit economics: Calculate contribution after variable costs (payment processing, fraud operations) before applying fixed operating expenses.

Fintech models require careful attention to regulatory capital requirements and loss provisioning that can significantly impact cash flow timing.

Beancount + Fava: practical tips​

BQL is SQL‑like: Use SUM(position) to aggregate and COST(...) to render amounts. YEAR(date)/MONTH(date) help build monthly time series. Export results to CSV and paste into your model.

Fava provides visualization: Use built‑in account reports and charts. Fava can plot two‑column BQL results (date/value) directly.

Income accounts are negative: This is by design in double-entry bookkeeping. Multiply by -1 when converting to positive revenue series for charting.

Reconciliation is key: Your model should exactly match your ledger balances for cash, revenue, and major expense categories each month.

Minimal chart of accounts (COA) mapping​

Keep it simple; consistency beats excessive detail.

SaaS:

• Income:Subscriptions:* • Income:Services (one‑off)
• Expenses:COGS:{Hosting,Support,API} • Expenses:{S&M,R&D,G&A}
• Liabilities:DeferredRevenue

Marketplace:

• Income:Marketplace:{Commissions,Fees} • Assets:Clearing:Escrow
• Expenses:Variable:{Processing,Chargebacks}

E‑commerce:

• Income:Store:Sales • Income:Store:Refunds (negative)
• Expenses:COGS:{Product,FreightIn} • Expenses:Variable:{Shipping,PaymentFees,Packaging}
• Assets:Inventory:*

Sanity checks (put these under a "QA" sheet)​

Revenue triangle closes: bookings → billings → revenue → deferred revenue roll‑forward should all reconcile.

Cash bridges: beginning cash + CFO + CFI + CFF = ending cash; reconcile to ledger balances monthly.

Headcount math: hires × ramp timeline × fully-loaded cost = department totals.

Unit economics: contribution margin ≥ 0, payback periods < acceptable thresholds, Rule of 40 trajectory makes sense.

Churn realism: don't hide contraction; report GRR and NRR side by side with supporting detail.

Copy‑paste formulas​

SaaS MRR waterfall (sheet layout)​

Rows: months Columns: Start MRR, New, Expansion, Churn, Contraction, End MRR

End MRR = Start + New + Expansion - Churn - Contraction
ARR = End MRR * 12
Quick Ratio = (New + Expansion) / (Churn + Contraction)

E‑commerce contribution​

Net Sales = Gross Sales - Discounts - Returns
Variable Costs = COGS + Fulfillment + Payment Fees + Variable Marketing
Contribution Margin ($) = Net Sales - Variable Costs
MER = Total Revenue / Total Marketing Spend
Inventory Turnover = COGS / Avg Inventory
DIO = (Avg Inventory / COGS) * 365

Marketplace liquidity snapshot​

Liquidity = % of listings transacting within N days

Track: Orders per active buyer, Active sellers, Repeat purchase rate, GMV, Take rate.

Further reading​

• Beancount BQL documentation for advanced queries and Fava for reporting
• SaaS metrics: Magic Number methodology (Scale Venture Partners); comprehensive benchmarks (OpenView)
• Rule of 40 / Rule of X framework (Bessemer Venture Partners)
• Marketplace metrics deep dive (Andreessen Horowitz's "13 Metrics")
• E‑commerce fundamentals (Shopify merchant resources)

Pro tip​

Keep models lean and actionable. Weekly, paste actuals from Beancount, rerun your dashboard, and adjust just three things: acquisition, retention, and margin. Everything else is often noise that distracts from the core drivers of your business.

The best financial models are living tools that help you make better decisions, not static artifacts that gather digital dust. By connecting your model directly to your accounting system, you ensure it remains grounded in reality while still providing the forward-looking insights you need to grow your business effectively.