How much can an environmental organization raise with a silent auction?

Short answer: how many access items your staff and volunteers will support, and whether work-party volunteers were on the list.

Working it out from members and who will lead a walk

The strongest lots are access items, and their ceiling is people rather than demand.

• Members, split between those who attend work parties and those who only subscribe
• How many access items staff and volunteer leaders will actually commit to leading
• Adjacent communities — birding, botany, walking, photography — which are organized and local
• The cost of the work you are funding: acres, metres of hedgerow, a monitoring season

The second input is a hard cap. Selling more walks than anybody will lead raises money this year and loses the volunteers who would have led them next year.

What moves it

Access items, and how many

Walks, surveys, field station nights. The ceiling is who will lead them, not demand — ask before setting a goal.

Work-party volunteers

The most committed and least-asked group, and the ones who can describe the work credibly to their own networks.

Whether the goal is in units of work

Acres, metres, a monitoring season. Members fund the specific and skip the general fund.

Adjacent communities

Birders, botanists, walkers and photographers are organized, local and interested in exactly your ground.

Setting the goal

Name the work with its real cost, publish it, and report with a photograph of the site — before and after, which almost nothing else in fundraising can offer as plainly.

Goal and budget mechanics: fundraising goals and budget.