Bollinger Bands
Calculate Bollinger Bands instantly with the exact formula and a worked example.
Bollinger Bands
Moving average SMA(20)
Standard deviation σ(20)
Multiplier k
Current price
Upper band
105
Lower band
95
%B
0.8
Band width
10%
More about: Bollinger Bands
What it calculates
The “Bollinger Bands” calculator computes Upper band from 4 parameters: moving average sma(20), standard deviation σ(20), multiplier k, current price.
Used by investors to estimate returns, project savings, and analyze a portfolio.
Example calculation
With parameters Moving average SMA(20) = 100, Standard deviation σ(20) = 2.5, Multiplier k = 2, Current price = 103 the result is 105.
How to use
- Enter moving average sma(20), standard deviation σ(20), multiplier k and current price — each field above is adjustable with a slider.
- Upper band is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
Related calculators
FAQ
What is compound interest?
Compound interest means you earn returns not only on your original principal but also on previously earned interest. Formula: A = P · (1 + r/n)^(n·t). Over long periods this produces exponential growth.
How much do regular contributions matter?
A lot. Adding a fixed amount every month and reinvesting earnings dramatically increases the final value, especially over 20–30 years, because each contribution compounds for the remaining term.
What is the Rule of 72?
A quick estimate for doubling time: years ≈ 72 / annual return %. At 8% your money doubles in about 9 years; at 12%, in about 6 years.
What return rate should I assume?
Historically the S&P 500 has returned about 10% per year before inflation (around 7% after). Use a conservative figure for planning and remember that past performance does not guarantee future results.
More calculators in this category
Explore related free tools