Exponential Smoothing Forecast Calculator
Simple exponential smoothing combines the latest observation with the previous forecast. A larger alpha reacts more strongly to the latest value; a smaller alpha smooths more aggressively.
How to use this calculator
- Enter the most recent actual value using the units shown beside the field.
- Enter the previous forecast using the units shown beside the field.
- Enter the smoothing factor alpha using the units shown beside the field.
- Review the calculated values and check that the assumptions match your scenario.
- Change one input at a time when comparing scenarios so you can see which assumption drives the result.
Formula and assumptions
New forecast = α × latest actual + (1−α) × previous forecast.
- This method has no explicit trend or seasonality component. Evaluate forecast errors on historical holdout data before using it operationally.
- The result is computed from the values you provide; it does not fetch external rates, live account data or local rules.
Worked examples
Worked example
Actual 108, previous forecast 100 and alpha 0.35 produce a next forecast of 102.8.
Example inputs: Most recent actual value = 108, Previous forecast = 100, Smoothing factor alpha = 0.35.
Compare the displayed output with your own measurements before using it in a decision.
Understanding the result
This method has no explicit trend or seasonality component. Evaluate forecast errors on historical holdout data before using it operationally.
Results are estimates based on the stated model. If the situation depends on measured conditions or contractual specifications, use those source values rather than typical assumptions.
Important notes
This method has no explicit trend or seasonality component. Evaluate forecast errors on historical holdout data before using it operationally.
Frequently asked questions
What formula does this calculator use?
It uses the method described above: New forecast = α × latest actual + (1−α) × previous forecast.
What should I verify before relying on the result?
This method has no explicit trend or seasonality component. Evaluate forecast errors on historical holdout data before using it operationally.
Can I compare different scenarios?
Yes. Change the inputs while keeping units and definitions consistent, and record the assumptions used for each scenario.
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Related explanations
Learn the method behind the number or compare the terminology before using the calculator.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.