Custom forecasting models in Looker Studio with parameters

Have you ever wanted to explore what-if scenarios in your dashboard, like “What if traffic increases by 15% next quarter?” or “What would revenue look like with a 25% growth in orders?” With parameters, you can create fully interactive custom forecasting models in Looker Studio that give users the power to experiment and project outcomes based on growth assumptions.

In this post, I’ll show you how to implement custom forecasting models in Looker Studio using the Superstore Products dataset. It’s a great way to add interactivity to your reports, especially for business cases, marketing simulations, or ecommerce planning.

🔧 Step 1: Create a growth rate parameter

To implement custom forecasting models in Looker Studio, let’s start by adding a parameter that allows users to define a percentage growth rate.

1. Go to Resource > Manage added data sources > Edit your data source
2. Click on Add a Parameter
3. Name it: Growth Rate %
4. Set the Data type to Number
5. Set Minimum value to 0, Maximum to 100
6. Set Default value to 10 (or whatever you prefer)
7. Click Save

This parameter will represent the percentage increase (e.g. 10 for 10%).

🧮 Step 2: Build the Forecast Calculation

Let’s say we want to forecast Gross revenue based on a growth scenario. We’ll apply the selected percentage to the current value.

1. Go to Resource > Manage added data sources > Edit your data source
2. Click Add a Field > Add calculated field
3. Name it: Forecasted Revenue
4. Use this formula:

Gross revenue * (1 + Growth Rate % / 100)

This creates a dynamic field where the value increases depending on the growth rate selected by the user.

📊 Step 3: Visualise custom forecasting models in Looker Studio

Now let’s put that forecast into a chart. You can:

• Create a time series chart with the metric Gross revenue
• Add Forecasted Revenue as a second metric
• Title the chart something like “Projected Gross Revenue”

This allows for an easy side-by-side comparison between actual and projected values.

💡 Optional: Use different colours or add a line chart with both metrics for visual contrast.

🎛️ Step 4: Add a slider control

Now it’s time to give your users control over the growth rate so we can see custom forecasting models in Looker Studio in action.

1. Click Add a Control > Slider
2. Set the control field to Growth Rate %
3. Adjust the min/max range if needed (e.g. 0 to 100)

This allows viewers to explore different growth scenarios by sliding between values without editing or guesswork required.

💼 Use case example: Revenue projections

Using the Superstore Products dataset:

• Suppose current Gross revenue in September is £309,770.
• A user selects a 25% growth rate via the slider.
• The Forecasted Revenue will now show £387,212.

This technique works beautifully for:

• Traffic growth simulations
• Campaign impact estimations
• Upselling or product expansion scenarios
• Budget or ROI forecasting

✨ Final touches

To make your forecasting model even more powerful:

• Add a comparison table showing:
  • Current revenue
  • Forecasted revenue
  • Difference (Forecasted Revenue - Gross revenue)
• Use conditional formatting to highlight large growth impacts
• Add explanatory text or tooltips to guide your users

✅ Final thoughts

Custom forecasting models in Looker Studio let you transform static dashboards into smart, interactive tools. With a simple growth rate parameter and a bit of maths, you can simulate future revenue, traffic, or sales in a way that feels intuitive and useful for decision-makers.

Once you set this up, you can expand it to other metrics like Quantity, or Net revenue, depending on your dataset and analysis goals.

❓FAQs