Startup Scenario-Planning Software: Compare Runway, Mosaic, Jirav, Causal, and LivePlan

Published by the Uniflow AI editorial team

What should startup scenario-planning software help you decide?

Startup scenario-planning software should connect operating assumptions—such as hiring, pricing, conversion, churn, and fundraising—to financial outputs such as revenue, expenses, cash balance, and runway. The main search intent is comparative: founders and finance teams are evaluating whether they need a spreadsheet, a business-plan tool, or dedicated FP&A software.

CB Insights reported that 38% of startup failures in its dataset were attributed to running out of cash or failing to raise new capital on 3 March 2021. That finding makes cash runway, financing timing, and downside cases central requirements rather than optional features.

The software should also test demand assumptions, not only costs. CB Insights attributed 35% of startup failures to no market need, so pricing, conversion, churn, and revenue growth deserve the same attention as payroll and operating expenses.

Eric Ries, entrepreneur and author of The Lean Startup, describes the operating environment directly: “A startup is a human institution designed to create a new product or service under conditions of extreme uncertainty.” A model that changes assumptions quickly is therefore more useful than a forecast that only records one fixed view of the future.

How is scenario planning different from a static spreadsheet or forecast?

A forecast usually represents the most likely expected outcome, while scenario planning compares multiple internally consistent outcomes such as base, upside, and downside cases. The distinction concerns the planning method, although products may use different terminology.

A spreadsheet can model scenarios, but it generally requires manual data imports, formula maintenance, version control, and access governance. Whether dedicated software is justified depends on model complexity, contributors, integrations, and reporting requirements; the comparison is a practical assessment rather than a quantified independent benchmark.

A useful test is whether a change to one operating driver flows through the model. For example, a delayed hire should affect payroll, cash balance, runway, and potentially fundraising timing without requiring disconnected formulas to be rebuilt manually.

Clayton M. Christensen, Scott D. Anthony, and Erik A. Roth wrote in Seeing What’s Next: “The only way to know whether your assumptions are valid is to test them.” This principle treats a financial model as a set of testable assumptions rather than a guaranteed prediction.

[Editor's note: Public research did not provide an independent, apples-to-apples benchmark for forecast accuracy, implementation time, error rates, or total cost of ownership across these products. Add new independent evidence before making performance claims.]

Which startup scenario-planning tools should you compare?

The main categories are startup-focused financial modelling platforms, strategic-finance and FP&A systems, flexible visual modelling tools, and business-plan software. Separating these categories prevents a business-plan product from being compared as if it offered the same workflow as a finance-led planning platform.

The table describes capabilities from vendor documentation and available comparative research, not independent product testing. Product features, connectors, implementation details, and pricing change frequently, so vendor documentation should be checked before purchase.

Public pricing for Runway, Mosaic, Jirav, Causal, and LivePlan requires current verification. [Editor's note: Add verified plan prices, implementation fees, and contract terms before publication if a price comparison is required.]

What should a startup model for hiring, runway, and fundraising include?

A defensible startup model should include fully loaded headcount cost, revenue drivers, cash movements, and financing assumptions. Fully loaded headcount cost means salary plus employer taxes, benefits, recruiting costs, location effects, and other personnel expenses.

A hiring scenario should include the role, start date, salary, employer taxes, benefits, recruiting cost, location, and any ramp period before expected productivity. UK and US employer-cost assumptions should not be treated as interchangeable because payroll and employment rules differ by jurisdiction.

A fundraising scenario should include the expected round date, amount raised, valuation or price per share, fees, and resulting ownership. Users should verify whether a product models priced equity rounds, SAFEs, convertible notes, option-pool changes, and post-money ownership.

Runway is commonly represented as available cash divided by net monthly cash burn, where burn is the cash a company spends beyond the cash it receives. This is only an approximation when burn changes materially, revenue is seasonal, or fundraising and working-capital movements are included.

Tax assumptions also need geographic treatment. The US federal corporate income-tax rate is 21%, while the UK main corporation-tax rate is 25% for company profits above £250,000 and a small-profits rate of 19% applies to profits of £50,000 or less, subject to associated-company rules.

How should a founder build base, upside, and downside cases?

The most useful scenario structure begins with actuals, identifies operating drivers, and then changes a limited number of important assumptions. A downside case should describe an operational cause—such as slower conversion, higher churn, delayed hiring, lower pricing, payment delays, or a missed funding round—rather than apply an arbitrary percentage reduction.

Our analysis identifies this driver-based approach as a practical information gap in many software comparisons. It tests the mechanism behind a result, which helps a founder connect a cash warning to an action such as pausing hiring or starting fundraising.

Use the following sequence to create a model:

1. Connect or import actuals. Import historical revenue, expenses, cash, payroll, and accounting data where available. Runway, Jirav, and Mosaic publish documentation describing integrations and financial-planning workflows.

2. Define operating drivers. Identify measurable inputs such as leads, conversion rate, average contract value, churn, hiring date, salary, payroll burden, payment terms, and cloud costs. Steve Blank’s business-model work supports testing assumptions while the model is being developed.

3. Build a base case. Use the most supportable assumptions for revenue, costs, hiring, cash balance, and financing timing. The base case should be a decision reference, not a claim that the outcome is certain.

4. Create upside and downside cases. Change a limited number of key drivers, such as sales conversion, churn, hiring timing, pricing, or fundraising date. Causal and Runway documentation describes variable-driven scenario modelling, but the exact recommended sequence is vendor-specific.

5. Model hiring separately. Include start date, role, salary, employer taxes, benefits, recruiting costs, location, and ramp time. This prevents a salary-only model from understating workforce commitments.

6. Model fundraising and dilution. Add round date, amount, valuation or price per share, fees, and resulting ownership. Carta documentation is relevant to cap-table and dilution logic, but treatment differs by instrument and jurisdiction.

7. Review runway and trigger points. Calculate cash balance under each case and connect thresholds to actions, such as pausing hiring or beginning fundraising. CB Insights’ 38% cash-related failure figure explains why these triggers matter.

8. Compare forecast with actual results. Track variance by driver, revise assumptions, and preserve prior scenarios so management can see what changed. Jirav, Runway, and Mosaic publish workflows related to reporting and planning, but cross-vendor processes remain unverified.

Which product fits a pre-seed company versus a finance-led startup?

A pre-seed founder preparing an investor plan may need straightforward revenue, cost, cash-flow, and funding assumptions, making LivePlan a relevant category to investigate. A startup with recurring planning cycles, multiple contributors, and connected accounting or payroll data may need a dedicated FP&A or financial-modelling platform.

Runway is positioned for venture-backed startups and scaling finance teams. Mosaic is positioned toward larger startups and finance-led companies, while Jirav targets small and midsize businesses needing structured FP&A.

Causal is relevant when a team wants flexible, visual, formula-driven models. Its custom variables can represent financing assumptions, pricing logic, and headcount, but users should confirm data-source connectivity and product-tier limitations.

The company stage should not be the only selection criterion. The number of contributors, required integrations, cap-table depth, geographic payroll logic, reporting cadence, and need to preserve historical scenarios can materially affect fit.

What should you check before buying startup planning software?

A buyer should validate the model’s decision coverage rather than choose from a feature list alone. The key question is whether the product can connect the assumptions that drive a startup’s most important decisions to clear cash, runway, ownership, and operating outputs.

Use this purchasing checklist:

• Confirm whether actual accounting, payroll, CRM, billing, and HRIS data can be connected or imported.
• Check whether hiring logic includes employer taxes, benefits, recruiting costs, start dates, locations, and ramp periods.
• Verify support for priced rounds, SAFEs, convertible notes, option pools, valuation, and post-money ownership if dilution matters.
• Test whether a pricing, conversion, churn, or fundraising-date change flows through to cash and runway.
• Confirm whether UK and US tax and payroll assumptions can be represented separately.
• Ask how the product compares forecast with actual results and preserves prior scenarios.
• Request current pricing, implementation requirements, connector limitations, and contract terms.
• Treat vendor customer stories as marketing evidence unless the reported outcome has a specific, attributable metric.

The available research does not establish that one listed product produces more accurate forecasts than another. A responsible comparison should therefore prioritize transparent assumptions, workflow fit, and verifiable capabilities instead of unsupported accuracy rankings.

Why does downside planning matter over several years?

Downside planning matters because startup survival and capital availability can change over time. The US five-year survival rate for private-sector establishments born in March 2013 was 49.9%, and the ten-year survival rate for the same cohort was 34.7%, according to the US Bureau of Labor Statistics, updated 24 April 2024.

Near-term conditions can also be volatile. The one-year survival rate for US private-sector establishments born in March 2022 was 79.6%, according to the same BLS source.

Fundraising assumptions should be stress-tested against market conditions. NVCA and PitchBook reported approximately $314 billion of US venture funding in 2021, followed by approximately $213 billion in 2022 and approximately $170 billion in 2023; the exact series should be checked against the relevant report edition before publication.

The UK context also supports contingency planning. The Office for National Statistics reported a UK annual business birth rate of 11.7% and death rate of 10.0% in 2022, while the Department for Business and Trade reported approximately 5.5 million private-sector businesses and 27.2 million employees at the start of 2023.

In our analysis of these figures, scenario planning is most valuable when it turns uncertainty into explicit decisions. The model does not remove uncertainty; it shows how hiring, demand, pricing, tax, and funding assumptions affect the actions available to the team.

Key Definitions

Scenario planning: A planning method that compares multiple internally consistent outcomes, such as base, upside, and downside cases, by changing selected assumptions.

Financial modelling: The use of linked assumptions and formulas to represent a company’s revenue, costs, cash, financing, and ownership outcomes.

FP&A: Financial planning and analysis, covering budgeting, forecasting, variance analysis, and management reporting.

Runway: An estimate of how long available cash may last, commonly approximated by dividing cash by net monthly cash burn.

Net cash burn: The amount by which cash spending exceeds cash received over a period.

Fully loaded headcount cost: The total personnel cost of an employee, including salary, employer taxes, benefits, recruiting costs, location effects, and related expenses.

Dilution: A reduction in an existing owner’s percentage ownership after a company issues new shares or other ownership interests.

Cap table: A record of a company’s ownership, including shares, investors, option pools, and other equity interests.

Frequently Asked Questions

What is startup scenario-planning software?

Startup scenario-planning software links operating assumptions—such as hiring, pricing, conversion, churn, and fundraising—to outputs such as revenue, expenses, cash balance, and runway. Vendor implementations differ, so current product documentation should be checked.

How many scenarios should a startup create?

A common operating structure is a base case, an upside case, and a downside case. No authoritative source in the available research establishes a universal required number, so the appropriate number depends on the decisions being made.

Can scenario-planning software model fundraising dilution?

Some platforms connect to cap-table data, while others require custom assumptions or a separate cap-table tool. Verify support for priced rounds, SAFEs, convertible notes, option pools, and post-money ownership before buying.

How should a startup model a hiring scenario?

Include the role, start date, salary, employer taxes, benefits, recruiting costs, location, and ramp period. Salary-only models can understate the cost of adding an employee.

Is Excel enough for startup scenario planning?

Excel or Google Sheets can model scenarios, but they generally require manual imports, formula maintenance, version control, and access governance. Dedicated software becomes more relevant as model complexity, contributors, integrations, and reporting requirements increase.

Should UK and US startups use the same financial assumptions?

No. Tax, payroll, employment costs, accounting treatment, reporting requirements, and fundraising conventions differ. UK and US models should represent jurisdiction-specific assumptions separately.