Cannabis Yield Efficiency Calculator

Compare harvest efficiency

Enter final dry, trimmed harvest weight, total installed grow-light wattage, and active canopy area. The calculator reports grams per watt and grams per square foot. Ounce and pound entries are converted to grams before calculation.

A 500-gram harvest under 600 watts is approximately 0.83 grams per watt. Across a 16-square-foot canopy, it is about 31.3 grams per square foot.

Use consistent boundaries

Decide which fixtures and which canopy area belong to the measured harvest. Do not compare one tent’s yield with wattage or area from a different zone. Use actual fixture draw rather than a model name or an old equivalent-watt claim.

Dry weight must be comparable

Record trimmed, dried weight at a consistent moisture endpoint. Wet harvest weight, untrimmed branches, and partially dried flower make comparisons misleading. Cultivar, veg time, plant count, quality targets, environmental control, and crop health all influence the result.

Efficiency is not the only goal

A higher ratio does not automatically mean better quality, safety, or profitability. Use this measurement alongside energy cost, harvest quality, labor, cycle length, and environmental performance.

Improve your records

• Measure actual fixture power when possible.
• Use the same dry-weight method every cycle.
• Record canopy dimensions before harvest.
• Compare similar cultivars and systems.

This calculator describes past performance. It does not predict or guarantee future yield.