Twin Prime Calculator

The Twin Prime Calculator is a free online tool used to check if two numbers are twin prime.

Twin Prime Calculator

Eg, Is 71 and 73 a twin prime? Enter 71 into the first input box and enter 73 into the second input box.

What is a twin prime?

A twin prime number is a pair of two prime numbers in which each prime number is either 2 less or 2 more than the other number. The prime numbers in a twin prime have a prime gap of 2. For example, (3, 5) is a twin prime.

By definition, we can derive two conditions for twin prime:

Both numbers must be prime numbers.
The difference between these two numbers is 2.

Such as: (3, 7) is not a twin primes, because the difference between them is not 2. (7, 9) is also not a twin prime because 9 is not a prime.

First 100 twin primes

- (3, 5)
- (5, 7)
- (11, 13)
- (17, 19)
- (29, 31)
- (41, 43)
- (59, 61)
- (71, 73)
- (101, 103)
- (107, 109)
- (137, 139)
- (149, 151)
- (179, 181)
- (191, 193)
- (197, 199)
- (227, 229)
- (239, 241)
- (269, 271)
- (281, 283)
- (311, 313)
- (347, 349)
- (419, 421)
- (431, 433)
- (461, 463)
- (521, 523)
- (569, 571)
- (599, 601)
- (617, 619)
- (641, 643)
- (659, 661)
- (809, 811)
- (821, 823)
- (827, 829)
- (857, 859)
- (881, 883)
- (1019, 1021)
- (1031, 1033)
- (1049, 1051)
- (1061, 1063)
- (1091, 1093)
- (1151, 1153)
- (1229, 1231)
- (1277, 1279)
- (1289, 1291)
- (1301, 1303)
- (1319, 1321)
- (1427, 1429)
- (1451, 1453)
- (1481, 1483)
- (1487, 1489)
- (1607, 1609)
- (1619, 1621)
- (1667, 1669)
- (1697, 1699)
- (1721, 1723)
- (1787, 1789)
- (1871, 1873)
- (1877, 1879)
- (1931, 1933)
- (1949, 1951)
- (1997, 1999)
- (2027, 2029)
- (2081, 2083)
- (2087, 2089)
- (2111, 2113)
- (2129, 2131)
- (2141, 2143)
- (2237, 2239)
- (2267, 2269)
- (2309, 2311)
- (2339, 2341)
- (2381, 2383)
- (2549, 2551)
- (2591, 2593)
- (2657, 2659)
- (2687, 2689)
- (2711, 2713)
- (2729, 2731)
- (2789, 2791)
- (2801, 2803)
- (2969, 2971)
- (2999, 3001)
- (3119, 3121)
- (3167, 3169)
- (3251, 3253)
- (3257, 3259)
- (3299, 3301)
- (3329, 3331)
- (3359, 3361)
- (3371, 3373)
- (3389, 3391)
- (3461, 3463)
- (3467, 3469)
- (3527, 3529)
- (3539, 3541)
- (3557, 3559)
- (3581, 3583)
- (3671, 3673)
- (3767, 3769)
- (3821, 3823)
Interestingly, 5 is the only prime number that belongs in two pairs of twin primes. In other words, it is the only number that has two twin primes. (3, 5) and (5, 7).

The sum of any pair of twin primes is always divisible by 12, except for the pair (3, 5).

How to use the twin prime calculator

The procedure to use the twin prime calculator is as follows:

1Enter 2 positive integers in the two input boxes respectively.
2Click calculate button to check whether the input pair of numbers is a twin prime.
3Click the Reset button to start a new verification.

Solved examples using the twin prime calculator

Example 1: Is 11 and 13 a twin prime?

Enter 11 into the first input box.

Enter 13 into the second input box.

Then click Calculate button, as shown in the figure, 11 and 13 is a twin prime.

Example 2: Is 13 and 17 a twin prime?

Enter 13 into the first input box.

Enter 17 into the second input box.

Then click Calculate button, as shown in the figure, 11 and 17 is not a twin prime. Because the difference between them is not 2.

Example 3: Is 31 and 33 a twin prime?

Enter 31 into the first input box.

Enter 31 into the second input box.

Then click Calculate button, as shown in the figure, 31 and 33 is not a twin prime. Because 33 is not a prime.

Twin Prime Calculator