Every business has questions that need modelling before committing real money. What happens to cash flow if sales drop 15%? Should we hire or outsource? What if our main supplier fails and lead times double?
Most teams answer these questions in spreadsheets. That works until it does not — until the model has forty tabs, three people who understand it, and assumptions buried in cells nobody audits. At that point, organisations look at SaaS scenario planning tools. But the market for those tools is fragmented and surprisingly rigid, and 89% of finance professionals still end up using Excel alongside them anyway.
We build custom scenario modeling software for UK businesses. Instead of fitting your thinking into a vendor’s template, we start with the decisions you actually need to make and build a tool around that.
Why off-the-shelf scenario tools fall short
The SaaS market for scenario planning is crowded — Anaplan, Workday Adaptive Planning, Vena, Prophix, Causal, Jirav — but the same complaints come up repeatedly:
- Rigid financial templates. Most platforms assume a standard P&L, headcount budget, and sales forecast structure. If your revenue model is complex (multi-tier pricing, territory-based commissions, usage-based billing, partner splits), the templates break or require expensive workarounds.
- Per-user licensing that escalates. Enterprise tools like Anaplan charge roughly £8,000 per model builder per year and £1,500 per contributor. Costs balloon as more people need access. Vena and Prophix follow similar patterns.
- Long, costly implementations. Anaplan implementations commonly run six to twelve months and £40,000 to £120,000 in consulting fees alone. Vena users have reported twenty-month timelines to full ROI. That is a long wait for a tool that still might not match your workflow.
- Hidden costs beyond the licence. Data migration (£8,000-£40,000), integration middleware if no native connector exists (£4,000-£25,000), training (£4,000-£25,000), and premium support (15-25% of annual licence). Actual total cost frequently exceeds the headline price by 50% or more.
- Integration gaps. Native connectors cover common accounting packages and ERPs, but if you run proprietary, legacy, or industry-specific systems, you are left building custom middleware at extra cost — or entering data by hand.
- Vendor lock-in. Proprietary data formats, formula syntax, and model structures create high switching costs. If the vendor raises prices or gets acquired, you have limited options.
- Spreadsheet sprawl persists. Because the tools cannot accommodate every edge case, finance teams maintain parallel spreadsheets for the bits that do not fit. Data gets stale, version control breaks, and the platform becomes a reporting layer rather than a genuine decision tool.
For organisations with standard structures and modest scenario needs, these tools can work well enough. But if your business is more complex, you end up paying enterprise prices for software that still does not do what you need.
What we build instead
We start with your actual decision-making process — the questions your CFO, operations director, or board keep asking — and build software that answers them directly.
- Your model, not a template. We map your revenue drivers, cost structures, and operational variables before writing any code. If your margin calculation involves complex commission tiers, multi-entity consolidation with intercompany eliminations, or industry-specific cost allocation, the software models that natively.
- Driver-based assumptions you control. You define the drivers (growth rates, headcount, COGS percentages, churn rates, raw material costs) and override them per scenario. Changes propagate automatically through the model.
- Unlimited scenarios, no per-user fees. Run three scenarios or three hundred. Add users as your team grows without licensing costs scaling alongside.
- Direct integrations with your actual systems. We build connections to your accounting package (Xero, QuickBooks, Sage), CRM (Salesforce, HubSpot), HR/payroll, and any proprietary or legacy systems — pulling data automatically rather than via manual export/import.
- Built for UK compliance. GDPR data handling, FCA audit trail requirements for financial services, Making Tax Digital awareness for cash flow forecasting, and UK data residency options as standard.
- Modular architecture. Start with financial scenarios and add workforce planning, supply chain modelling, or sensitivity analysis as separate modules without rebuilding what already works.
- Ownership. You pay for the build and own the result. No subscriptions, no vendor dependency, no scrambling if someone else’s pricing changes.
Core features
Each build is configured to your requirements, but these are the modules we typically deliver:
Scenario engine
- Multi-scenario creation with driver-based or assumption-based modelling
- Side-by-side comparison (best case, base case, downside, and any custom scenarios)
- Automatic recalculation when assumptions change, across all interconnected variables
- Multi-dimensional modelling by business unit, geography, product line, or time period
Analysis and visualisation
- Executive dashboards with live KPIs and scenario results
- Sensitivity analysis identifying which assumptions have the greatest impact on outcomes
- Variance analysis comparing forecast to actuals
- Waterfall and tornado charts for presenting results to boards and investors
- Monte Carlo simulation for probabilistic outcomes where uncertainty is high
Collaboration and governance
- Role-based access: viewers, editors, approvers — with row-level security so division managers see only their data
- Immutable audit trail recording who changed which assumption, when, and why
- Four-eyes approval workflows for critical scenarios
- Commenting, version control, and scenario branching for collaborative planning
- Scenario locking after sign-off to prevent post-approval changes
Integration and data
- Automated data refresh from accounting systems, CRM, HR, and payroll
- Two-way sync with Excel and Power BI for teams that still want to work in familiar tools
- REST API and webhook support for pushing scenario results to downstream systems
- Import/export in CSV, Excel, JSON, and PDF formats
- Data warehouse connectivity (Snowflake, BigQuery, Redshift) for historical driver analysis
Reporting and compliance
- Custom report builder matching your branding, terminology, and preferred metrics
- Scheduled report distribution to stakeholders
- GDPR-compliant data handling with retention policies and right-to-deletion support
- Regulatory reporting formats for FCA stress testing, IFRS requirements, or sector-specific obligations
Mobile and access
- Browser-based with responsive design for tablet and mobile use
- Permissions-controlled mobile access so senior staff can review scenarios on the move
- UK-hosted infrastructure with encryption at rest and in transit
How the build works
1. Discovery (2-3 weeks) We interview the people who actually make decisions — CFOs, FP&A analysts, operations directors — to understand what scenarios matter, which drivers you track, what data you already collect, and where your current process breaks down. We audit your existing systems and map out integrations. We also identify the historical data needed (typically three to five years of financials, headcount, and pipeline data) and plan the data migration.
2. Core development (6-10 weeks) Agile process with fortnightly demos. We build the data model, scenario engine, and UI in parallel. The interface is designed around how your team already thinks — if your planners think in production runs and capacity, the software reflects that language, not generic financial jargon. We integrate with your accounting system, CRM, and other sources early so you are working with real data from week four onward.
3. Testing and launch (2-4 weeks) Your team runs acceptance tests comparing scenario outputs against known historical results. We validate data imports, check formula propagation, and stress-test performance with large scenario volumes. Deployment is phased — typically starting with one team or business unit before rolling out more broadly.
4. Training and handover (1-2 weeks) Hands-on workshops for both technical administrators and business users (two to four hours per group). Written guides and recorded walkthroughs provided. We document all model logic so your team is not dependent on us to understand how things work.
5. Support and evolution (ongoing) First twelve months include quarterly health checks. After that, flexible maintenance plans — most clients add new modules or scenario dimensions on a quarterly or half-yearly basis as their needs evolve.
Costs and ownership
SaaS scenario planning can be surprisingly expensive once you account for the full picture:
| Low-cost SaaS (e.g. Jirav) | Mid-tier SaaS (e.g. Causal) | Enterprise SaaS (e.g. Anaplan) | Custom build | |
|---|---|---|---|---|
| Year 1 | ~£40,000 | ~£48,000 | ~£160,000 | £60,000-£92,000 |
| 3-year total | ~£88,000 | ~£112,000 | ~£320,000 | £84,000-£124,000 |
| 5-year total | ~£136,000 | ~£192,000 | ~£480,000 | £124,000-£172,000 |
Estimates for a team of ten active users. SaaS figures include licence, implementation, integration, and support. Custom figures include development, integration, and annual maintenance.
The custom build becomes cost-competitive around year two to three. Beyond that, the gap widens because SaaS licensing repeats annually while your maintenance costs stay flat. And crucially, at the end of five years you own a working asset rather than having spent six figures on something you cannot keep.
Project costs depend on complexity, number of integrations, and the depth of modelling required. An MVP (single-entity financial scenarios, core drivers, comparison views, dashboard) typically runs £40,000 to £65,000. A fuller build with multi-entity consolidation, sensitivity analysis, Monte Carlo simulation, and multiple system integrations sits in the £80,000 to £160,000 range. We provide detailed estimates after an initial consultation, which is free and carries no obligation.
Industry applications
Scenario modelling means different things in different sectors. Here is what we typically build:
Financial services Interest rate shock modelling, credit default scenarios, liquidity stress testing, and portfolio rebalancing under different market conditions. FCA-compliant audit trails and immutable assumption logging. Regulatory stress test documentation that meets MiFID II retention requirements.
Manufacturing Supplier failure scenarios, production capacity modelling (two-shift versus three-shift), raw material price sensitivity, and demand volume planning. Useful for capital expenditure decisions where you need to model payback under different output assumptions.
Healthcare and pharma Patient volume and bed capacity scenarios under different admission rates. Workforce planning for clinical and support staff. R&D pipeline modelling for pharmaceutical companies tracking time-to-market and regulatory approval probabilities. CQC-compliant reporting where required.
Retail and e-commerce Seasonal demand modelling, promotional pricing scenarios (discount percentage, timing, channel allocation), inventory turnover optimisation, and multi-channel revenue allocation between online and physical stores.
Professional services Resource allocation across projects and clients, utilisation rate modelling, project profitability forecasting, and hiring scenarios based on pipeline confidence. Useful for firms outgrowing spreadsheet-based capacity planning.
Construction and property Development cost inflation scenarios, occupancy rate modelling, interest rate impact on financing, and bid pricing with risk-adjusted margins. Lease-up timeline modelling for commercial property.
Energy and utilities Demand forecasting under different weather and pricing scenarios, commodity cost sensitivity, renewable generation modelling, and grid capacity expansion planning. HSE compliance considerations built in where relevant.
Technology and SaaS Cash burn modelling under different growth and churn assumptions, headcount planning (engineering versus sales versus support), pricing model comparison (per-seat versus per-company versus usage-based), and R&D investment scenario evaluation.
Common Questions About Custom Scenario Modeling Tools
How does custom development cost compare to SaaS scenario planning tools?
SaaS platforms like Anaplan or Vena typically cost between £25,000 and £80,000 per year in licensing alone, plus implementation fees of £15,000 to £120,000. Per-user pricing (often £1,500 to £10,000 per user per year) escalates as your team grows. A custom build starts from roughly £50,000 to £80,000 for an MVP, with annual maintenance of £8,000 to £16,000. Over three to five years, total cost of ownership is often comparable or lower -- and you own the result outright.
What is the typical development timeline?
An MVP covering single-entity financial scenarios, core driver assumptions, side-by-side comparison, and a dashboard takes four to six weeks. A fuller build with multi-entity consolidation, accounting system integration, sensitivity analysis, and workflow approvals typically runs twelve to twenty weeks in total. We phase delivery so you start getting value early rather than waiting for a single big launch.
What data do we need to provide?
At minimum, three to five years of historical financials: P&L, balance sheet, and cash flow. Beyond that, headcount and payroll data, sales pipeline, cost breakdowns (fixed versus variable), and any KPIs you already track. We handle data extraction and cleaning as part of the build, but starting with well-organised source data does speed things up.
Can you integrate with our existing systems?
Yes. Common integrations include Xero, QuickBooks, Sage, and other accounting packages; Salesforce and HubSpot for pipeline data; HR and payroll systems like ADP; and data warehouses such as Snowflake or BigQuery. If you run proprietary or legacy systems without standard APIs, we build custom connectors directly.
What about data security and compliance?
We build with UK GDPR from day one, including data minimisation, retention policies, and right-to-deletion support. For regulated sectors, we can add immutable audit trails (who changed which assumption, when, and why), role-based access with four-eyes approval, and FCA-compliant stress testing documentation. Hosting options include AWS UK, Azure UK, or on-premise if data sovereignty is a requirement.
Do you provide training for our team?
Yes. We run hands-on workshops (typically two to four hours per user group) covering scenario creation, assumption editing, interpreting results, and exporting reports. We also provide written guides and recorded walkthroughs. For ongoing support, the first twelve months include quarterly health checks; after that, flexible maintenance plans are available.
What if SaaS is actually enough for us?
For some businesses it is. If your model fits standard P&L and headcount templates, you have fewer than ten scenario planners, and you only need best-case/base-case/downside views on a quarterly cycle, a tool like Jirav or Causal may serve you well. Where custom makes more sense is when your revenue model is non-standard, you need deep integration with proprietary systems, you run high volumes of scenarios, or you have specific regulatory obligations that off-the-shelf tools do not cover properly.