There’s no “safe” number of cigarettes you can smoke per day. Any number of cigarettes can increase your risk of developing cancer.But the more you smoke, the more likely you are to get cancer. A 2021 studyTrusted Source looked at 229,028 Australian participants to estimate how likely people are to develop cancer by age 80,

In the study, only 1% of people who’d never smoked developed lung cancer by age 80. The study found that the risk of developing lung cancer increases to 14% if you smoke cigarettes.If you smoke one to five cigarettes per day, your risk is around 7.7%, and if you smoke more than 35 cigarettes per day, you’ll have a 26.4% chance of developing lung cancer by age 80.Bear in mind that you don’t need to smoke in order to develop smoking-related cancers. Secondhand smoke also increases your risk of developing lung cancer.