CSA share value calculator
Is a CSA share worth it, and what should a share cost?
Showing for United States
What you save over the season (negative means the shop is cheaper)
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- What each box you collect costs you
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- What you use of each box, at shop prices
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- What you use over the season, at shop prices
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- Share of each box you must use for the share to pay off
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- Boxes you collect
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Price one typical box at what you would really pay for the same food where you shop now, at the same size and quality. Add it up once from a box you have had.
Food you do not use is not a saving. Leave the share empty if you use all of it.
Share price for the season
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- Share price per week
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- What a member saves over the season
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- The season's boxes at retail
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- Takings from all members
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The share price is rounded up to the cent.
This prices a share from what the box is worth to members. To check that the price covers your costs, use the cost-plus calculator; for the members and ground you need, use the CSA members and acres planner.
Enter your numbers to see the result.
Planning a farm stand, a CSA or a shop? TallyTill is free to start.
Get started with TallyTill for freeUse this calculator in an AI chat
You can ask Claude, ChatGPT or another AI app to work this out for you, and this calculator opens right inside the chat. You connect TallyTill to your AI app once. It is free, and there is no account and no sign-in.
AI apps call add-ons like this connectors, apps or MCP servers. They all mean the same thing: a way for the AI to use a tool someone else made.
1. Copy this address
2. Add it to your AI app
Claude (claude.ai and the Claude desktop app)
- Open Customize, then Connectors.
- Press + Add, then Add custom connector.
- Name it TallyTill calculators, paste the address and press Continue.
- Under Authentication choose No sign in, then press Add.
- In a new chat, press + at the bottom left, choose Connectors and switch TallyTill calculators on.
On Claude's free plan you can add one custom connector.
ChatGPT
- In Settings, turn on Developer mode. OpenAI moves this switch from time to time; it is usually with the settings for apps and connectors.
- Add a new connector (ChatGPT may call it an app), paste the address and choose No authentication.
- In a new chat, choose TallyTill from the tools menu, or type @ and pick it.
Not every ChatGPT plan lets you add your own connector. If you cannot find the option, your plan may not include it.
Using another AI app? Look in its settings for MCP, add the address as a remote server, and choose no sign-in.
3. Ask your question
Say "use TallyTill", so the AI uses the calculator instead of doing the sum itself. For example:
"Use TallyTill: Is a CSA share worth it, and what should a share cost?"
What you will see
- The calculator opens in the chat with the numbers you gave already filled in. Change any number and the answer updates.
- If a number is missing, the box is highlighted, or the AI asks you for it in plain words.
- The answer links back to this page, so you can check the working.
- The first time, your AI app asks if it may use TallyTill. Choose Allow.
The calculators take numbers only. They never ask for your name, your email or a password.
How this is worked out
For a member: the boxes you collect are the weeks less the weeks you miss. The season's value is what one box would cost where you shop, times the share of it you use, times the boxes you collect, rounded to the cent. What you save is that value less the share price. Each box you collect costs the share price divided by the boxes. The share of each box you must use for the share to pay off is the share price divided by the boxes' full shop value. For a farm: the share price is the box's retail value times the weeks, less your member discount, rounded up to the cent.
A worked example
Example numbers only; use your own. A 600.00 share for 20 weeks, a box that would cost 38.00 at the shop, two weeks missed and 90 percent of each box used: the 18 boxes you collect are worth 615.60 to you, so you save 15.60, and each box costs you 33.33. The share pays off if you use at least 87.72 percent of each box. A farm whose box is worth 35.00 at retail, for 20 weeks, with members paying 10 percent less, charges 630.00 a share, or 31.50 a week.
Nothing you type here is saved.