CSA Share Calculator

A community supported agriculture share is a pre-season subscription: members pay before planting and receive a portion of whatever the farm harvests each week. Pricing starts from the retail value of a representative box, usually 6 to 10 items weighing 8 to 12 pounds, multiplied by the number of delivery weeks, then discounted 10 to 20 percent to reward the member for paying early and carrying part of the production risk. A 24-week season is the most common length in temperate North America, with 20 to 28 weeks the usual band and extended-season programs running longer using hoop houses and storage crops. Half shares are priced at roughly 55 to 65 percent of a full share rather than exactly half, because packing, transport, and pickup-site costs per member barely change with box size. The economics hinge on two numbers the grower controls only partly. Production cost typically absorbs 50 to 65 percent of share revenue on diversified vegetable farms once labor is paid at a real wage, leaving a gross margin that must still cover the operator's own draw. Break-even membership is fixed cost divided by the contribution each share makes after its own variable cost, so a farm with 20,000 dollars of seasonal fixed cost and 300 dollars of variable cost per 600 dollar share needs about 67 members. The main caveats are that upfront revenue is not the same as profit, since the cash arrives months before most of the expense; that annual member attrition of 20 to 40 percent means recruitment is a permanent cost; and that a share is a claim on a harvest, not on a guaranteed basket, so crop failure is shared with members and must be disclosed in the agreement.

The model has two distinct roots. In Japan, groups of consumers concerned about pesticide residues and food adulteration began contracting directly with organic growers around 1971, an arrangement known as teikei, meaning partnership or cooperation, promoted by the Japan Organic Agriculture Association. In German-speaking Europe, farms influenced by Rudolf Steiner's biodynamic teaching experimented with community-financed agriculture in which the farm budget, rather than a per-item price, determined what members paid. Both traditions replaced the market transaction with an ongoing relationship between eaters and a particular piece of land. The idea reached the United States in 1986 with two independent starts. At Indian Line Farm in Egremont, Massachusetts, Robyn Van En and John Root Jr. sold shares in an apple harvest and then in vegetables, and Van En went on to popularize the term community supported agriculture and to found an early advocacy network. In the same year the Temple-Wilton Community Farm in New Hampshire was organized by Trauger Groh, who had brought the biodynamic community-farm approach from Germany, together with Lincoln Geiger and Anthony Graham. Growth was rapid: a handful of farms in the late 1980s became several hundred by the mid-1990s, and USDA census figures in the 2010s counted several thousand farms reporting CSA sales. Software platforms and hybrid market-style shares emerged in the 2010s, and the 2020 pandemic produced a sharp, temporary surge in subscriptions as buyers sought alternatives to crowded retail.