# Fibonacci number tester

## World's simplest math tool

Free online Fibonacci number tester. Just enter your number on the left and it will automatically get checked if it's in the Fibonacci sequence. There are no ads, popups or nonsense, just an awesome Fibonacci checker. Enter a number – test its Fibonacci status. Created by math nerds from team Browserling.

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Fibonacci number tester tool
What is a fibonacci number tester?

This tool tests if the given number is a Fibonacci number. You can check many values at the same time by writing each integer on a new line. There are three types of checks in the options. The first one makes a complete analysis of all numbers and displays each number's status (if it's a fibo or not a fibo). The second filters out only those integers that are Fibonacci numbers. And the third does opposite of what second does – it filters and displays all values that are not Fibonacci numbers. Mathabulous!

Fibonacci number tester examples
Click to use

Random Fibonacci Numbers

In this example we input random values on the left and do a full analysis of them. In the output on the right, you get a description of each number. It shows whether it is a Fibonacci number or not.

35
5
51
7
21
65
58
15
82
8

35 is a not Fibonacci number
5 is a Fibonacci number
51 is a not Fibonacci number
7 is a not Fibonacci number
21 is a Fibonacci number
65 is a not Fibonacci number
58 is a not Fibonacci number
15 is a not Fibonacci number
82 is a not Fibonacci number
8 is a Fibonacci number

**Required options**

Show a detailed description of all numbers.

A Hundred Integers

In this example we load the first hundred integers for testing and return a list of only those that are Fibonacci numbers. There are only 11 Fibonacci numbers between 1 and 100.

0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100

0
1
2
3
5
8
13
21
34
55
89

**Required options**

Show only a list of Fibonacci numbers.

Large Fibonacci Numbers

This example shows that the tool can check if arbitrarily large integers are Fibonacci integers. Here we invert the display results and print only those values that are not Fibonacci numbers.

81055900096023504197206408605
50095301248058391139327916261
11825896447871834235346346346
19134702400093278082235234534

11825896447871834235346346346
19134702400093278082235234534

**Required options**

Show only those values that are not Fibonacci numbers.

Pro tips
Master online math tools

You can pass input to this tool via

__?input__query argument and it will automatically compute output. Here's how to type it in your browser's address bar. Click to try!
https://onlinemathtools.com/test-fibonacci-number

__?input__=35%0A5%0A51%0A7%0A21%0A65%0A58%0A15%0A82%0A8&test-all-numbers=true
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