FORECAST.ETS Function in Excel: Forecast With Seasonality

⏱ 1 min readUpdated 28 September 2026

StatisticsLevel: ExpertAvailable in: Excel 2016+

In this article
  1. Syntax
  2. Examples
  3. Example 1
  4. Related functions

FORECAST.ETS uses exponential smoothing and detects seasonal patterns — the engine behind Excel’s Forecast Sheet.

Syntax

=FORECAST.ETS(target_date, values, timeline, [seasonality], [data_completion], [aggregation])
Argument What it means
seasonality 1 = detect automatically; or 12 for monthly data with a yearly cycle.

Examples

Example 1

=FORECAST.ETS(A38, B2:B37, A2:A37, 12)

Next month’s sales from three years of monthly history.

💡 The timeline must have even steps (every month, every day). Gaps trigger #NUM!.

FORECAST.LINEAR · TREND

📚 Part of the free Excel course: Beginner → Expert · Try it in the Formula Lab or ask the AI Helper.

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