Finance · Investments & Markets

Bollinger Bands Calculator

Calculate a moving average and entered multiples of population standard deviation.

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Quick guide

How to use this calculator

  1. Enter observations in chronological order and choose the visible period or convention.
  2. Use prices and volumes with consistent units and equally spaced periods where required.
  3. Read the formula and seeding convention before comparing results with another platform.

Calculation method

Calculation method

Upper/lower band = latest-period SMA ± multiplier × population standard deviation.

Technical indicators are deterministic transformations of entered historical data. Approximate floating results are explicitly formatted as estimates.

Worked example

Worked example

A 20-period input with multiplier 2 produces the middle, upper, and lower bands.

Upper/lower band = latest-period SMA ± multiplier × population standard deviation.

Supported inputs

Precision and limits

Visible input limits

Lists accept up to 2,000 fixed-decimal rows. Period fields disclose their whole-number limits. Approximate indicators reject observations whose significant differences cannot be represented reliably at their entered scale.

No live market data

The page does not fetch prices, volumes, corporate actions, exchange calendars, or benchmark data. Enter adjusted or unadjusted observations deliberately.

Decision boundary

Indicators describe entered history. They do not predict price direction, identify a suitable trade, measure every risk, or recommend an investment.

Calculator-specific assumptions

This page uses population standard deviation for the selected window.