Estimating the Number of Cigarette Butts Discarded in the Environment
Enter values in each box below. If you are unsure of what to enter, click the
i How can I find this? icon next to each box. Click Calculate to estimate the number of cigarette butts discarded per year.
Number of adults in the community.
Use a search engine to find the number of adults in your chosen location. Government websites with census data are typically reliable sources. If you are in the United States, you can use the Census Quick Facts website. Once you enter the name of a city, it gives you (A) the total population and (B) the population <18. Subtract B from A, and you get the # of adults.
Surface area of the community where these adults live (in km2)
Use a search engine or government website to find the surface area for an official administrative area, such as a city or province. Use tools offered by Google Maps or other mapping software to determine surface areas for smaller or nonstandard geographic areas.
% of adults who smoke
Use a search engine to find the percentage of adults in your chosen location who smoke. If you are in the United States, you can use the CDC Places Interactive Map, click the Health Risk Behaviors tab, and choose “Current Smoking”.
Average number of cigarettes smoked per day
This information is not consistently reported and varies between communities and between individuals who smoke. Consider that a pack contains 20 cigarettes and that some people smoke one pack per day or more. In California, the number of cigarettes smoked per day is estimated to be 5 to 10.
% cigarette butts littered
Enter the share of butts you think end up as litter rather than in bins. The discard rate can vary from community to community, with the best estimates ranging from approximately 40% to 70%.
Estimated number of adults who smoke
—
Adults x % who smoke
Discarded butts per year
—
Adults who smoke × cigs/day × % discarded × 365
How much is that?
The following comparisons are offered to better understand the scale of cigarette butt pollution and its potential environmental impact.
Each comparison presents a hypothetical scenario (e.g., length of chain of cigarette butts) or a hypothetical equivalent (e.g., lethal doses, Olympic-size swimming pools with polluted water) to better understand the scale and potential impact of CB pollution. These figures do not present actual exposure scenarios. Real-world exposure and impact depend, among others, on where butts are discarded, the degradation and leaching of CBs, dilution, street cleaning, exposure pathways, stormwater system design, and water treatment.
- This many cigarette butts are equivalent to — discarded butts per square meter.
- End to end, this many cigarette butts would stretch about — km (— miles).
- End-to-end, this many cigarette butts would stretch — times around the Earth at the equator.
- Within 24 hours, this many butts can release an estimated — to — kg (— to — lb) of nicotine in water.
- Considering the upper limit of the oral lethal dose of nicotine for a child weighing 10kg is 140 mg, the amount of nicotine released by this many cigarette butts is equivalent to — lethal doses.
- Considering the predicted No Effect Concentration (PNEC) of 2.4 mg of nicotine per 1000 L of water, this much nicotine would pollute the water in — Olympic-size swimming pools (— cubic meters) above the no effect threshold.
- Considering that each cigarette filter contains, on average, 0.12 grams of microplastics, the total amount of microplastics that can be released by this many cigarette butts is — kg (— lb).
Assumptions: 1 butt ≈ 1 inch (2.54 cm). Earth circumference = 40,075 km. Nicotine released per butt in 24 hours: 1.2 mg. Lethal dose for a 10 kg child: 10–140 mg. The aquatic Predicted No Effect Concentration (PNEC) threshold us 2.4 mg of nicotine per 1000 L of water.
Reporting Guidelines
The quality of CB Calculator estimates depends on the validity and uncertainty of its inputs. When reporting CB Calculator estimates, we recommend that the user report the input values (e.g., ranges of estimates), sources of evidence, and assumptions, along with range estimates for discarded CB, environmental impact metrics, and limitations. The following reporting checklist is recommended:
- Geographic region (e.g., name of city, state, province) and year(s) for which the estimates are calculated
- The size of the adult population and the source of this information
- The estimated percentage of adults who smoke cigarettes (e.g., midpoint and range estimates) and the source of this information
- The estimated number of cigarettes consumed per day (e.g., midpoint and range estimates) and the source of this information
- The estimated percentage of discarded CBs (e.g., midpoint and range estimates) and the source of this information
- Exclusions: groups of individuals (e.g., youth, visitors, commuters), types of tobacco products, or spaces that were excluded
- Output framing: Round estimates to reflect uncertainty and present ranges that describe the potential environmental impact metrics. Remind the reader that real-world exposure depends on where CBs are discarded, on CB degradation, on the conditions of chemical leaching, and on exposure pathways.
Limitations
- This calculator relies on estimates (e.g., smoking prevalence) and assumptions (e.g., litter rate). The accuracy of the calculated values depends on the validity of the user-provided estimates and assumptions.
- Unless the exact number of adults who smoke, their daily cigarette consumption, and their specific discard percentage are available for a particular area, we recommend using lower and upper bounds of a credible range for smoking prevalence, daily smoking rate, and discarded proportion. This helps the calculator provide a plausible range of discarded CBs. For example, instead of using a daily smoking rate of 8 cigarettes, a range of 5 to 10 cigarettes may better reflect the uncertainty about the community’s smoking habits. Similarly, considering a range of plausible discard percentages allows the user to see how different assumptions impact the projected amount of CB pollution.
- The calculator is designed to estimate the number of cigarette butts littered by adult residents, and it does not include visitors or residents under 18 who smoke. As a result, the calculated number of discarded cigarette butts underestimates the total if younger residents or visitors smoke in the area. This underestimation will be most significant in locations with many visitors or a high proportion of youth. To address this, information about youth or visitors and their smoking habits can be used to separately estimate the number of cigarette butts they discard. Overestimation may also happen when adult residents spend much of their time outside their official residence areas (e.g., bedroom communities) and discard cigarette butts elsewhere (e.g., their workplaces).
- The definition of smoking prevalence typically refers to tobacco products that produce smoke through burning. This includes cigarettes with and without filters, as well as cigars, cigarillos, pipes, and waterpipes (e.g., hookah, shisha). Using such a broad definition of smoking prevalence can lead to overestimating discarded cigarette butts, especially in communities where unfiltered tobacco products are common. To avoid this overestimation, users should adjust prevalence estimates to specifically refer to filtered cigarettes.
- The proportion of discarded CBs used in calculations assumes that all discarded CBs stay in the environment, where they leach pollutants and degrade input microplastics. In communities with comprehensive public and private environmental services, some discarded CBs in areas cleaned by these services will enter the managed waste stream, and a smaller amount than projected will contribute to leaching and microplastics remaining in the environment. To adjust for this bias, users should modify the discard proportion accordingly.
References
Crosby, L. M. (2024). Unravelling the Risk of Poisoning From Nicotine-Containing Tobacco Products in Children Less Than Five Years of Age. Nicotine & Tobacco Research, 27(3), 378-386. https://doi.org/10.1093/ntr/ntae044
Matt, G. E., Greiner, L., Tran, K., Gibbons, J., Vingiello, M., Stigler Granados, P., Shadbegian, R., & Novotny, T. E. (2025). Estimating the accumulation and re-accumulation of commercial tobacco, electronic cigarette, and cannabis waste based on a stratified random sample of census blocks. PLoS One, 20(1), e0313241. https://doi.org/10.1371/journal.pone.0313241
Novotny, T. E., Bialous, S. A., Hill, K., Hamzai, L., Beutel, M., Hoh, E., Mock, J., & Matt, G. E. (2022). Tobacco Product Waste in California: A White Paper. https://merg.sdsu.edu/tpwwp/
Roder Green, A. L., Putschew, A., & Nehls, T. (2014). Littered cigarette butts as a source of nicotine in urban waters. Journal of Hydrology, 519, 3466-3474. https://doi.org/https://doi.org/10.1016/j.jhydrol.2014.05.046
Soltani, M., Shahsavani, A., Hopke, P.K. et al. Investigating the inflammatory effect of microplastics in cigarette butts on peripheral blood mononuclear cells. Sci Rep 15, 458 (2025). https://doi.org/10.1038/
Valcárcel, Y., Alonso, S. G., Rodríguez-Gil, J. L., Castaño, A., Montero, J. C., Criado-Alvarez, J. J., Mirón, I. J., & Catalá, M. (2011). Seasonal variation of pharmaceutically active compounds in surface waters of Madrid, Spain and potential ecotoxicological risk. Chemosphere, 84(10), 1336–1348.
Roder Green, A. L., Putschew, A., & Nehls, T. (2014). Littered cigarette butts as a source of nicotine in urban waters. Journal of Hydrology, 519, 3466-3474. https://doi.org/https://doi.org/10.1016/j.jhydrol.2014.05.046