How to Build a Cash Plan Before a Series A Fundraise

What Series A investors are actually funding

A Series A cash plan must show how new capital can produce five to ten times growth over two years and reach the milestones required for another round.

• Revenue assumptions should connect a proven customer segment and sales channel to bookings, implementation capacity, usage, and cash collection.
• Hiring should remove specific growth constraints, such as pipeline generation, sales capacity, or onboarding delays, rather than follow a departmental wish list.
• The downside case should show how slower hiring, inefficient GTM organization, delayed client launches, or weaker transaction volume changes runway, hiring, and fundraising timing.

Series A investors need to see where their capital goes. For B2B SaaS companies processing payments, transaction revenue moves with volume and take rate. The cash plan must absorb that volatility while preserving enough cash to execute.

Which growth motion should your model fund?

Fund the customer segment and sales motion that already produce strong customers with manageable effort. Modeling tools can calculate outcomes, but they cannot make that judgment.

• Trace each won customer to its origination channel, buying trigger, and the person who closed the deal.
• Compare sales-cycle length and implementation effort. A channel with fewer leads may produce faster, better-qualified customers.
• Model channels separately. One blended growth rate hides differences in conversion, sales capacity, onboarding cost, and time to live revenue.

In my experience running finance inside venture-backed companies, the strongest Series A plans connect each major hire or spending increase to a repeatable motion. If founder-led sales drive most wins, the model should show how new sellers learn that motion rather than assume immediate productivity. If partnerships produce the best accounts, capital should support partner acquisition and implementation capacity. The spreadsheet should reflect an operating decision you have already made.

Building the rolling 24-month operating model

Build the model in monthly columns covering the next 24 months. Monthly granularity matches the accounting close and makes hiring dates, implementation lags, settlement timing, and cash balances visible. Use greater detail for the next few months and broader assumptions for later periods.

Organize calculations around 15 to 25 operating drivers rather than hundreds of hardcoded lines. Qualified pipeline should drive bookings and revenue. Headcount should drive payroll and operating expenses. For payments companies, processing volume and take rate should drive transaction revenue, while transaction costs, reserves, and settlement timing affect gross margin and cash. Each driver should flow through the profit and loss statement, working capital, and closing cash balance.

Roll the model forward after every monthly close. Replace the completed forecast month with actuals, add one month at the far end, and investigate material variances before changing assumptions. Keep formulas and scenario logic intact. A rolling model updates the outlook without erasing the original budget or requiring a fresh spreadsheet each month.

Modeling bookings from the bottom up

Build bookings from rep capacity and observed conversion, not an unsupported growth percentage.

• Set each rep’s monthly capacity using quota, expected attainment, and a month-by-month ramp curve.
• Check whether qualified pipeline can support that capacity at your observed win rate.
• Move signed bookings into revenue only after the expected implementation period.

Use the capacity formula of annual quota multiplied by expected attainment, then divide by 11 for monthly output. (Why 11 instead 12? Sales reps are people. Like everyone, they take vacations.) Apply a lower ramp factor to new hires based on your own cohorts. A $1,200,000 quota at 75% attainment produces $75,000 of monthly capacity before ramp adjustments.

Next, calculate the pipeline required to fill that capacity. If your qualified opportunities convert at 20%, each $1 of expected bookings needs $5 of qualified pipeline. Shift closed deals forward by the observed implementation lag before forecasting billing and cash receipts.

Add sellers only when a specific customer segment and acquisition channel already convert predictably. Generic sales expansion adds payroll immediately, while bookings arrive after recruiting, ramp, the sales cycle, and implementation.

Unit economics by segment and revenue stream

Model contribution margin separately for each revenue stream and customer segment. A blended margin can hide a profitable license product behind costly transaction volume, or vice versa.

• SaaS margin equals platform revenue less the direct cost of delivering and supporting the software.
• Transaction margin equals processed volume times take rate, less processing fees, transaction costs, and direct risk losses.
• Segment margins reveal whether enterprise customers produce enough contribution to justify longer sales cycles and heavier implementation work.

Use a written COGS policy because GAAP does not prescribe one SaaS definition. Include hosting, required third-party software, delivery-focused support, and implementation costs. Exclude sales and marketing, R&D, and general overhead. Support work tied to delivery belongs in COGS, while renewal or expansion work belongs in sales and marketing. Separate implementation costs when possible so they do not obscure recurring license margin.

Calculate CAC and payback by segment using its own sales cost, implementation effort, and contribution margin. If enterprise contracts repay CAC quickly but implementation capacity delays launches, add implementation staff before sales capacity. If a segment repays CAC slowly, more sales hires increase burn before they improve cash generation.

Runway, minimum cash, and the downside case

Set the minimum unrestricted cash balance first, then calculate when each scenario breaches it. A monthly forecast captures hiring and spending changes that a simple cash divided by net burn calculation misses.

• Base assumptions cover pipeline conversion, implementation timing, usage growth, take rate, settlement lag, reserves, and chargebacks.
• Downside assumptions reduce or delay inflows while increasing reserve funding, transaction costs, and chargeback losses.
• Financing need covers the milestone plan while preserving minimum cash through a delayed fundraising close.

Track processor reserves and merchant funds separately from operating cash. Payments companies should distinguish restricted balances from available cash, although financial statements reconcile both categories under cash flow reporting rules. Set the minimum around payroll, fixed commitments, settlement exposure, and a contingency buffer.

Compare each cash-out date with the fundraising calendar. Mercury recommends preparing once runway reaches 9 to 12 months because a raise can take 3 to 6 months. If the downside breaches your threshold, slow hiring, cut unproven channel spend, and start the raise earlier.

Worked example: a fictional B2B SaaS company

Consider LedgerPay, which starts with $80,000 in monthly SaaS revenue and $20 million in monthly payment volume. A 0.60% net take rate produces $120,000 in transaction revenue, while processing costs consume $80,000. Starting monthly revenue equals $200,000.

LedgerPay expands its sales team by four account executives, bringing the total to six. After a three-month ramp, each mature rep closes one customer per quarter. Each customer contributes $10,000 in monthly license revenue and $2 million in monthly payment volume after implementation. The model produces 36 new customers over 24 months.

By month 24, license revenue reaches $440,000 and payment volume reaches $92 million. Transaction revenue reaches $552,000 before $368,000 of processing costs. Total monthly revenue approaches $1 million, which supports the 5x growth case.

Headcount grows from 16 to 32 across sales, implementation, risk, and engineering. Monthly operating spend rises from $450,000 to $800,000. Net burn peaks at $520,000 before falling to $176,000.

With $4.5 million of cash and a $1 million minimum balance, LedgerPay needs at least $4.5 million and should start raising immediately. The downside case produces 25 customer wins and 20% lower usage. Higher reserves then bring the minimum cash date forward four months and increase the financing need to $6.5 million.

Founder checklist and cash-plan template

Use the checklist to test whether your cash plan connects operating decisions to financing needs.

• Set a 24-month forecast horizon with monthly detail.
• Limit your driver list to assumptions that materially change cash.
• Build sales capacity using rep ramp, quota attainment, conversion, and implementation timing.
• Calculate unit economics separately by customer segment and revenue stream.
• Track runway against a minimum unrestricted cash balance.
• Create a credible downside case with defined management responses.
• Connect each use of funds to hiring, growth, or operating milestones.

A practical template should keep inputs separate from calculations and investor-ready outputs.

• The assumptions tab holds commercial, cost, payment, and working-capital drivers.
• The monthly P&L tab calculates revenue, gross margin, and operating expenses.
• The cash flow tab captures settlement timing, reserves, chargebacks, and cash movements.
• The headcount tab records hiring dates and fully loaded employee costs.
• The scenario toggle switches the model between base and downside assumptions.
• The runway tab shows monthly burn, cash balance, minimum cash, and financing need.
• The investor outputs tab presents historical actuals, use of funds, milestones, hiring, and forecast scenarios.

What should your cash plan prove before you raise?

A credible cash plan shows how you make decisions when growth, timing, and cash move differently than expected. Investors assess whether your assumptions connect to operating actions and whether you can protect runway while reaching the milestones required for the next round. The spreadsheet supports that judgment. It cannot replace it.

If you want help building the plan, Bridges brings hands-on payments and fintech experience to forecasting, scenario design, and investor outputs.

If you are preparing a Series A for a B2B SaaS company that processes payments, get a clear read before you set a hiring plan or a fundraising date. Bridges can pressure-test the cash plan, downside case, and runway with you, and Bridges builds the investor-ready outputs once the operating decisions are set.