Formula
S₁=x₁; Sₜ=αxₜ+(1−α)Sₜ₋₁; next forecast=S_last.
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Initial level equals the first observation. No trend, seasonality or forecast interval is fitted.
Example Calculation
Example inputs
- Ordered observations: 10,20,30
- Alpha: 0.5
Observations 10,20,30 with alpha 0.5 produce smoothed values 10,15,22.5.
Frequently asked questions
How do I use this calculator?
Enter ordered observations, alpha. The result updates automatically. Use Reset to restore the example values.
What method does it use?
S₁=x₁; Sₜ=αxₜ+(1−α)Sₜ₋₁; next forecast=S_last.. Initial level equals the first observation. No trend, seasonality or forecast interval is fitted.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.