Moving Average Filter Calculator

How it is calculated

The tool reads every number in the text box and slides a window of w consecutive values along the series. Each output is SMAi = (xi + xi+1 + ... + xi+w-1) / w. Only complete windows are used, so n values give n - w + 1 results and the first w - 1 positions have no output; the count is shown as well. The window must be a whole number of at least 1 and no larger than the number of values, otherwise there is no result. A window of 1 returns the series itself. Separators can be spaces, new lines, semicolons or commas. If the text contains a space, new line or semicolon, a comma between two digits is read as a decimal comma (1,5 means 1.5); with no whitespace at all, commas separate values. Forms such as .5 and 1e3 are understood. Results are rounded to two decimals.

Common mistakes

• Expecting one output per input value. The filter uses full windows only, so the result is shorter by window - 1 points.
• Mixing comma styles, such as 10,12, 14,16. Because the text has a space, the commas between digits are read as decimals and you get 10.12 and 14.16 instead of four values. Pick one style: separate values with spaces or new lines, or use commas alone and dots for decimals.
• Choosing a window as long as the whole series and expecting a trend. That gives a single overall average, so pick a window much shorter than the data.
• Entering a fractional or zero window such as 2.5. The window must be a whole number of at least 1, and no longer than the series.
• Choosing too large a window and lagging the trend. A bigger window smooths more but reacts later to real changes.