Traditional annual budgets often become outdated quickly.
A company may create a forecast in January, but by June, market conditions, customer demand, operating costs, and business priorities may have changed significantly.
This is why many organizations use rolling forecasts instead of relying solely on fixed annual plans.
A rolling forecast continuously updates future projections by adding a new forecasting period as the current period ends. Rather than forecasting only until the end of the year, businesses maintain a constant planning horizon, such as the next 12 months, four quarters, or 24 months.
In this guide, you’ll learn what rolling forecasts are, why businesses use them, and how to build one in Excel.
What Is a Rolling Forecast?
A rolling forecast is a continuously updated financial forecast that extends the planning horizon whenever a period ends. In Excel, rolling forecasts are typically built using historical data, assumptions, formulas, and dynamic date structures that automatically extend future projections.
A rolling forecast is a forecasting model that always looks ahead a fixed number of periods.
Example:
Traditional Annual Forecast
January → December
Created once and rarely updated.
Rolling Forecast
Current Month
↓
Next 12 Months
Every month, a new month is added to maintain the 12-month forecast horizon.
Why Businesses Use Rolling Forecasts
Business environments change constantly.
Factors include:
- Customer demand
- Economic conditions
- Pricing changes
- New competitors
- Operating expenses
Rolling forecasts help organizations adapt to these changes more effectively.
Benefits include:
- Better planning
- Improved decision-making
- More accurate forecasts
- Greater business agility
Rolling Forecast vs Traditional Budget
| Traditional Budget | Rolling Forecast |
|---|---|
| Fixed period | Continuously updated |
| Annual focus | Ongoing planning |
| Less flexible | More adaptive |
| Updated infrequently | Updated regularly |
| Historical mindset | Forward-looking mindset |
Many organizations use both approaches together.
Understanding the Forecast Horizon
The forecast horizon defines how far into the future projections extend.
Common examples:
12-Month Rolling Forecast
Current Month
↓
Next 12 Months
18-Month Forecast
Current Month
↓
Next 18 Months
Quarterly Forecast
Current Quarter
↓
Next 4 Quarters
The horizon remains constant while the forecast moves forward.
Step 1: Gather Historical Data
Every forecast begins with historical performance.
Example:
| Month | Revenue |
|---|---|
| Jan | 50,000 |
| Feb | 52,000 |
| Mar | 55,000 |
| Apr | 58,000 |
| May | 60,000 |
Historical data provides the foundation for projections.
Step 2: Create a Time Structure
Create forecast periods.
Example:
| Month |
|---|
| Jan |
| Feb |
| Mar |
| Apr |
| May |
| Jun |
| Jul |
| Aug |
As months pass, new forecast periods will be added.
Step 3: Separate Actuals and Forecasts
A common layout looks like:
| Month | Revenue |
|---|---|
| Jan | Actual |
| Feb | Actual |
| Mar | Actual |
| Apr | Actual |
| May | Actual |
| Jun | Forecast |
| Jul | Forecast |
| Aug | Forecast |
This clearly distinguishes historical results from projected values.
Step 4: Define Forecast Assumptions
Forecasts rely on assumptions.
Examples:
| Variable | Assumption |
|---|---|
| Revenue Growth | 5% |
| Expense Growth | 3% |
| Inflation | 2% |
Store assumptions in separate cells for easy updates.
Example:
B1 = Revenue Growth Rate
Step 5: Build Revenue Forecast Formulas
Suppose May revenue is:
60,000
Expected monthly growth:
5%
June forecast:
=B6*(1+$B$1)
Result:
63,000
The forecast automatically applies the growth assumption.
Step 6: Extend Future Periods
Copy the formula forward.
Example:
| Month | Forecast Revenue |
|---|---|
| Jun | 63,000 |
| Jul | 66,150 |
| Aug | 69,458 |
Each month builds upon the previous projection.
Step 7: Forecast Expenses
Use similar logic.
Example:
Current expenses:
40,000
Expected growth:
3%
Formula:
=PreviousMonth*(1+3%)
This creates projected expense values.
Step 8: Calculate Profit Forecasts
Profit formula:
Revenue
-
Expenses
=
Profit
Excel formula:
=RevenueCell-ExpenseCell
Profit updates automatically as assumptions change.
Step 9: Build Dynamic Dates
Instead of manually entering dates:
Example:
=EDATE(A2,1)
This generates the next month automatically.
Benefits:
- Less maintenance
- Easier updates
- Reduced errors
Step 10: Add Actual Results
At month-end:
Replace forecast values with actual results.
Example:
Before:
| Jun | Forecast |
|---|---|
| 63,000 |
After:
| Jun | Actual |
|---|---|
| 64,500 |
The forecast horizon then moves forward.
Step 11: Extend the Forecast
When June becomes actual:
Add:
Next June
to maintain the planning horizon.
Example:
Current Month
↓
Next 12 Months
remains unchanged.
This is what makes the forecast “rolling.”
Example: 12-Month Rolling Forecast
January forecast includes:
Feb → Jan Next Year
By February:
Mar → Feb Next Year
The planning window continuously moves forward.
Using Excel Tables
Excel Tables improve rolling forecasts significantly.
Benefits:
- Automatic range expansion
- Dynamic formulas
- Easier reporting
Convert data into a table:
Ctrl + T
before building forecasts.
Using Growth Drivers
Many forecasts rely on business drivers.
Examples:
Sales Forecast
Driver:
Customer Growth
Revenue Forecast
Driver:
Average Sales Price
Expense Forecast
Driver:
Headcount Growth
Driver-based forecasting often produces more realistic results.
Scenario Planning
Most finance teams create multiple forecasts.
Best Case
High Growth
Expected Case
Normal Growth
Worst Case
Low Growth
This helps prepare for uncertainty.
Example Scenario Model
| Scenario | Growth Rate |
|---|---|
| Best | 10% |
| Expected | 5% |
| Worst | 2% |
Changing assumptions updates the entire forecast automatically.
Adding Charts
Charts help visualize projections.
Popular options include:
Line Charts
Show trends over time.
Combination Charts
Display:
Actuals
+
Forecasts
on the same chart.
This improves management reporting.
Variance Analysis
Compare forecasts against actual results.
Example:
| Metric | Forecast | Actual |
|---|---|---|
| Revenue | 63,000 | 64,500 |
Variance:
+1,500
This helps improve forecasting accuracy over time.
Real-World Example
A SaaS company forecasts:
- Monthly recurring revenue
- Customer growth
- Operating expenses
Each month:
- Actual results replace forecasts
- New forecast periods are added
- Assumptions are updated
- Reports are refreshed
Management always has visibility into the next 12 months.
Common Beginner Mistakes
Using Fixed Dates
Dynamic date formulas are more scalable.
Mixing Assumptions with Calculations
Keep assumptions separate.
Overcomplicating Models
Start simple and add complexity gradually.
Forgetting to Update Actuals
Forecast accuracy depends on current data.
Ignoring Scenario Planning
Multiple scenarios improve decision-making.
Best Practices
Keep Inputs Separate
Create dedicated assumption sections.
Use Dynamic Formulas
Reduce manual maintenance.
Update Regularly
Rolling forecasts are only valuable if maintained consistently.
Document Assumptions
Record the reasoning behind growth rates and projections.
Compare Forecasts to Actuals
Continuous improvement leads to more accurate forecasting.
Why Rolling Forecasts Are Popular
Rolling forecasts help organizations remain flexible.
Instead of relying on outdated annual plans, businesses can:
- React faster to change
- Improve financial visibility
- Support strategic planning
- Make better decisions
This is why rolling forecasts are increasingly common in modern finance teams.
Rolling forecasts provide a dynamic approach to financial planning by continuously extending the forecasting horizon as new information becomes available. Using Excel, organizations can build rolling forecasts that combine historical data, growth assumptions, dynamic formulas, and scenario planning to create more accurate and adaptable projections.
Whether you’re forecasting revenue, expenses, profits, or cash flow, rolling forecasts help ensure that decision-makers always have a forward-looking view of business performance.
FAQ
What is a rolling forecast?
A rolling forecast is a continuously updated forecast that maintains a fixed planning horizon, such as the next 12 months.
How is a rolling forecast different from a budget?
Budgets are usually fixed for a period, while rolling forecasts are updated regularly.
Why do finance teams use rolling forecasts?
They provide more flexibility and better visibility into future business performance.
Which Excel functions are useful for rolling forecasts?
Common functions include EDATE, IF, SUM, and forecasting formulas based on growth assumptions.
How often should rolling forecasts be updated?
Most organizations update them monthly or quarterly depending on business needs.