FP&A PlatformCustom SoftwareFree ToolsNewsPricing
Free Tool

Revenue Forecast Simulator

Enter your monthly revenue data and get a 12-month projection with conservative, base, and optimistic scenarios.

Monthly Revenue Data

Enter at least 6 months of revenue. Leave later months empty if you do not have the data yet.

$
$
$
$
$
$
$
$
$
$
$
$

Enter at least 6 months of revenue data to generate a forecast. 0/6 months entered.

How it works

This tool uses least-squares linear regression to find the underlying trend in your revenue data -- essentially drawing the best-fit line through your monthly numbers. It then projects that trend forward 12 months. When seasonality is enabled, the tool calculates a seasonal index for each month (how much that month typically deviates from the trend) and applies those patterns to the projection. The conservative and optimistic bands give you a realistic range by scaling the base forecast down and up by 20%.

The formula

Linear Regression: y = mx + b where: m = (n * sum(xy) - sum(x) * sum(y)) / (n * sum(x^2) - sum(x)^2) b = (sum(y) - m * sum(x)) / n x = month number, y = revenue Seasonal Index = actual / trend value for each month Projection = trend * seasonal index Conservative = base * 0.8 Optimistic = base * 1.2

Why it matters for your business

Revenue forecasting is the foundation of business planning. Whether you are preparing a budget, planning hires, negotiating with investors, or setting sales targets, you need a defensible projection of where revenue is heading. A data-driven forecast based on your actual numbers carries far more weight in a board meeting or pitch deck than a guess -- and the range between conservative and optimistic scenarios shows you have thought through the uncertainty.

Pro tip

12 months of data reveals seasonal patterns that 6 months cannot. If you only have 6 months, do not trust seasonal adjustments -- stick with the trend line.

Get deeper insights with James FP&A

These calculators are just the start. Connect your accounting data and get automated financial analysis, forecasting, and real-time dashboards.