> For the complete documentation index, see [llms.txt](https://chembl.gitbook.io/surechembl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chembl.gitbook.io/surechembl/chemical-search/filter-by-molecular-weight.md).

# Filter by molecular weight

When searching chemical structures in SureChEMBL, you may specify a particular range of molecular weights that are considered acceptable results. The default range of zero to 800 is designed to encompass the majority of small molecules most of interest to medicinal chemists.

<figure><img src="/files/gN0oPOn9IiYjh8jho7GC" alt=""><figcaption><p>Molecular weight filter</p></figcaption></figure>