This Fibonacci Calculator requires Javascript (which is NOT the same as Java).
Make sure Navigator (or Communicator) has Javascript enabled in your Preferences:
in Edit, Preferences, Advanced, check the box marked Javascript or Scripting.
Fibonacci and Lucas Number Calculator 1.1     For help, see lower down.
Series? Value or Range for i? Precision? Action buttons
From i=
To i=
The calculator is waiting... computing...

How to use this calculator

[Links followed from this page will open in a new window.]
  1. Select a series Fibonacci(i) or Lucas(i) or Rabbit(i).
  2. Type in a whole number value for i (which can be negative for Fibonacci or Lucas) in the From i= box.
  3. If you want to find all the values in a certain range, type a value in the To i= box also. Leave this blank if you just want a single value of a series.
  4. Select the precision of the computation: Exact or Approximate. (Ignored for Rabbit(i) and Initial digits.)
    the calculator will find Fibonacci(i), Lucas(i) for i into the thousands. This may take up to a minute or more depending on your computer. Also, if i is too large, the browser may quit unexpectedly! Sorry - I cannot predict or prevent this! 'i' values up to i=2000 should be OK and Fib(2000) has more than 400 digits.
    Immediate result. The length of the answer decreases as i gets larger, but the index i itself may have up to digits!
  5. Select an action:
    Show series
    outputs the Fib or Lucas series for i in the range.
    Initial digits
    Benford's Law relates to the distribution of the initial digits of Fibonacci and Lucas numbers. (The precision buttons are irrelevant.)
    Amaze me!
    Generates a correct, random expression involving two nth-roots whose sum is 1, as mentioned on The Lucas numbers page.
    Clear all
    clears all values and the output area.


The calculator requires JavaScript (not the same as Java!) and Internet Explorer 4 or Netscape Navigator 4 or Communicator 4 or later versions.

Netscape Navigator:

Make sure JavaScript is enabled in Navigator version 4 or later:
In Edit Menu - Preferences - Advanced, check the box marked 'JavaScript'.
Back to FIB Home Fibonacci Home Page
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16 April 1999