ROI Calculator

Build interactive ROI and business calculators for your visitors — directly in Concrete CMS, without writing code. Editors define inputs and formulas in the block dialog; visitors see the results update live as they move a slider or type a value. Ideal for marketing ROI, e-commerce KPIs, SaaS funnels, pricing and break-even calculators.

Highlights

• Flexible inputs – number fields or sliders with name, unit, variable key, min / max / step / default and help text
• Headings & groups – structure long forms with section headings
• Powerful formulas – + - * / ^ ( ), comparisons, round, floor, ceil, abs, min, max, sqrt, if(condition, then, else) and condition ? a : b; reference inputs by key or by {{Display Name}}
• Chained results – results can use other results, in any order; circular references are detected
• Number formatting per result – decimal places, thousands and decimal separator (e.g. 60.012,50 or 60,012.50) plus unit
• Live formula check in the editor – unknown variables, syntax errors and circular references are highlighted while typing
• Clear editor for large calculators – tabs for General / Parameters / Results, collapsible entries with a summary line, sorting via ↑/↓
• Custom CSS class per input and result – e.g. show "costs before" in red and "costs after" in green
• Live or on demand – results update instantly or after a click on "Calculate"
• Hide intermediate results – calculate helper values without showing them
• Three templates – Default, Modern and Neo
• Multiple calculators per page – each block instance works independently

Common Use Cases

• Marketing ROI simulations and budget scenarios
• E-commerce KPIs: orders, AOV, margin, ROAS, CPA
• SaaS funnels: leads → trials → subscriptions, ARPA, LTV, CAC, payback
• Pricing, break-even, savings and project calculators

Example

Security

• Formulas are evaluated with a maintained, patched expression parser (expr-eval-fork 3.x) – no eval, works with a strict Content Security Policy (no unsafe-eval needed)
• Formulas can only call whitelisted functions
• Help text HTML is sanitized, all output is escaped

Requirements

• Concrete CMS 9.0.5 or newer
• PHP 7.4 or newer (8.1+ recommended)
• Help tooltips in the Default template use the theme's Bootstrap 5 JS and Font Awesome (info icon)

Installation & Usage

1. Install the add-on via Dashboard → Extend Concrete.
2. Add the ROI Calculator block to a page.
3. General tab: title, description, optional "Calculate" button.
4. Parameters tab: add inputs (field or slider) and optional headings.
5. Results tab: add formulas and, if needed, a number format and CSS class.
6. Choose a template via the block's design options and save.

Tips

• Round to two decimals: round(expr, 2) – or simply set Decimal places to 2 in the result's number format.
• Avoid division by zero: if(denominator == 0, 0, expr) or denominator == 0 ? 0 : expr.
• Style individual values with the CSS class field, e.g. .roi-cost-before .roi-result-value { color: #c62828; }