How this dust collector filter area calculator works
A fabric filter collector needs as much filter area as the air volume divided by the filtering velocity. This page works out the required area first, then the side area of one bag from its diameter and length, and rounds up to the number of bags needed. It also works the ratio back out for the area as installed.
The relations applied are required area = air volume / filtering velocity, area of one bag = pi x diameter x length and bag count = round up of required area divided by one bag area. Only the cylindrical side is counted, with no allowance for the bottom or the cap. Enter the compartments and the offline count and the effective area = installed area x (total - offline) / total gives the ratio during cleaning. Areas and ratios are shown in US units with metric values in parentheses. Figures reflect October 2026.
Air to cloth ratios by filter media were not confirmed from an authoritative source, so no figures are supplied and the ratio is entered by you. Working out the required air volume from hood capture velocity and duct transport velocity, duct sizing, pressure drop and cleaning intervals, and collection efficiency are not covered. This calculator is for reference and does not replace design. Review by a qualified engineer is required.
Frequently asked questions
It depends on the filter media, the dust and the cleaning method, so no value by media type is offered here because none was confirmed from an authoritative source. Use the figure from the equipment maker data or the design standard you apply.
Yes. Rounding up gives more filter area than needed, so the ratio as installed comes out lower than the value entered. That is why the installed ratio is shown alongside.
If some compartments are taken offline while they are cleaned, less filter area is in use and the ratio rises. Enter the total and the offline count and the effective area and ratio for that condition are shown.