The calculator is used to test your eyesight and recognize the difference in color shades. After clicking on the first lighter field, the calculator will change colors and the countdown will begin. Each test takes 15 seconds. Search for a lighter field and click on it. Each subsequent test is more difficult. The test will be aborted if you do not give the correct answer within 15 seconds or if you make a wrong choice three times.

Thanks to the calculator, you can use several factors to check the degree of risk of a heart attack in the next ten years.

Vigenère cipher online encoder and decoder. Encrypt and decrypt any cipher created in a Vigenère cipher. You can use any shift and additionally a key for more precise text encoding.