Calculator Inputs
Example Data Table
Example uses a 3-period simple moving average on a short demand series.
| Period | Original Value | 3-Period Rolling Average |
|---|---|---|
| 1 | 120 | N/A |
| 2 | 128 | N/A |
| 3 | 133 | 127.00 |
| 4 | 140 | 133.67 |
| 5 | 138 | 137.00 |
Formula Used
Simple moving average: SMAt = (xt + xt-1 + ... + xt-n+1) / n
Weighted moving average: WMAt = Σ(xi × wi) / Σwi
Exponential moving average: EMAt = αxt + (1 - α)EMAt-1
For the exponential method, the first reported EMA is seeded with the simple average of the first full window.
How to Use This Calculator
- Paste your time-series observations into the data box.
- Select simple, weighted, or exponential averaging.
- Enter the window size you want to test.
- Add weights for weighted mode, or alpha for exponential mode.
- Choose decimal places and the starting period label.
- Press the calculate button to view summary metrics, the chart, and the detailed result table.
- Use the CSV or PDF buttons to save your output.
Frequently Asked Questions
1) What does a rolling average do?
A rolling average smooths short-term fluctuations by averaging nearby observations. It helps reveal trend direction, seasonality changes, and underlying movement in noisy time-series data.
2) What is the difference between simple, weighted, and exponential averages?
A simple average treats each value equally. A weighted average assigns custom importance to each value inside the window. An exponential average reacts faster because recent observations get more influence.
3) How should I choose the window size?
Use smaller windows when you need faster signal detection. Use larger windows when you want stronger smoothing. Testing several windows usually helps you balance responsiveness and stability.
4) Can I enter decimals, negative values, or pasted spreadsheet data?
Yes. The calculator accepts decimals, negatives, and values separated by commas, spaces, semicolons, or line breaks. Invalid tokens are ignored and reported in the notes area.
5) Why do the earliest periods show N/A?
The first periods do not yet contain enough observations to complete the selected window. The calculator waits until the full window is available before reporting a rolling value.
6) What alpha should I use for an exponential average?
Higher alpha values respond faster to recent changes, while lower values produce smoother lines. Leaving alpha blank applies the common default formula 2 divided by window plus 1.
7) What do the CSV and PDF downloads include?
The downloads include the calculated result table and summary context. CSV is ideal for spreadsheet work, while PDF is useful for reports, reviews, and quick sharing.
8) When is a rolling average better than a cumulative average?
Use a rolling average when recent behavior matters more than old history. A cumulative average blends everything together, which can hide newer shifts in the data.