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FORECAST.ETS.CONFINT Function
Summary
The FORECAST.ETS.CONFINT function returns a confidence interval for an exponential triple smoothing (ETS) forecast, providing a statistical range within which the actual future value is expected to fall with a specified probability.
Syntax
FORECAST.ETS.CONFINT(target_date, values, timeline, [confidence_level], [seasonality], [data_completion], [aggregation])Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| target_date | Number/Date |
Yes | The date or time for which you want the confidence interval bounds |
| values | Number Array |
Yes | Historical data values (Y values) used for forecasting |
| timeline | Date Array |
Yes | Corresponding dates/times for the historical values |
| confidence_level | Number |
No | Confidence level (95% default) between 0 and 99 |
| seasonality | Number |
No | Seasonality period (1=auto detect, 0=no seasonality) |
| data_completion | Number |
No | Gap filling method (1=interpolate, 0=zero, default=1) |
| aggregation | Number |
No | Aggregation method (1=average, 2=sum, 3=count, 4=minimum, 5=maximum, default=1) |
Using the FORECAST.ETS.CONFINT Function
FORECAST.ETS.CONFINT works alongside the FORECAST.ETS function to provide statistical reliability to your predictions. While FORECAST.ETS gives you a single point forecast, CONFINT delivers the upper and lower bounds of the prediction interval, helping you understand the uncertainty in your forecast.
Common FORECAST.ETS.CONFINT Examples
Basic Confidence Interval Forecast
=FORECAST.ETS.CONFINT(50, B2:B49, A2:A49, 95%)Returns the 95% confidence interval for the forecast at period 50 based on historical sales data.
Custom Confidence Level
=FORECAST.ETS.CONFINT(52, C2:C53, B2:B53, 90%, 12)90% confidence interval for 12-month seasonal forecast at period 52.
Frequently Asked Questions
Common Errors and Solutions
#VALUE!
Cause: Non-numeric values in values or timeline arguments
Solution: Ensure all values and timeline entries are numeric
#NUM!
Cause: Invalid confidence level outside 0-99 range
Solution: Use confidence level between 0 and 99
Notes
- Returns a single number representing the confidence interval half-width
- Multiply by -1 for lower bound or use positive for upper bound
- Requires matching count of values and timeline arrays
- Part of Excel's ETS (Exponential Triple Smoothing) forecasting suite
Compatibility
Available in: Excel 2016, Excel 2019, Excel 2021, Excel for Microsoft 365
Not available in: Excel 2013 and earlier, Excel for Mac 2011, Excel Online
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2016+, Excel for Microsoft 365