Free crop calculator

Onions yield calculator.

Turn your plant count or growing area into a cautious harvest range, estimated supermarket value and shareable result.

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Your crop and setup

Estimate the harvest.

Start with a cautious planning range, then adjust the price and costs to match what you actually buy.

Crop

What are you measuring?

Number of plantsGrowing area

Number of bulbsExpected growing resultComparable supermarket price (£/kg)Editable rounded default; use the price and quality you would actually buy.Your seeds, plants and growing costs (£)Include crop-specific compost, feed, seed and replacement supports.Carbon scenario

Yield, price, nutrition and carbon figures are estimates—not promises or carbon-accounting claims.

Your harvest value will appear here.

See a realistic yield range, retail comparison, food portions, break-even point and cautious climate estimate.

A better harvest

Good spacing and curing are as important as raw yield if you want bulbs to store.

Use the range as a planning guide. Variety, weather, pests, soil, container size and harvesting habits can move the real result substantially.

Read the RHS growing guide ↗