Cannabis Yield Estimator Calculator

Grams-per-watt and grams-per-plant measure yield from two independent angles — one tied to how much light energy you're pumping in, the other tied to how many plants you're growing — and they only agree when your plant count and lighting are well-matched for your experience level. Averaging the lower and higher result keeps a mismatch, like very few plants under very strong lights, from producing an inflated single-number estimate.

The medium multiplier ranges from 1.0x for soil up to 1.4x for aeroponics, reflecting that more actively managed root environments (coco coir at 1.15x, DWC hydro at 1.3x) tend to support faster nutrient and oxygen uptake at the roots. Since this multiplier is applied to both the wattage-based and plant-based estimates before they're averaged, switching from soil to aeroponics in the calculator raises your entire projected yield range by 40%, not just one output.

The veg-time factor starts at 0.6 for a 2-week veg and climbs toward 1.0 as veg length approaches 12 weeks, then plateaus — the calculator caps the benefit at that point because plants stop translating extra vegetative time into proportionally larger flowering canopy. Going from 6 to 10 weeks of veg raises this factor and thus your estimate, but pushing veg out to 16 weeks earns no additional credit in the model beyond the 12-week point.

Conservative is the lower of the two method results (grams-per-watt vs. grams-per-plant) and optimistic is the higher; the headline estimated yield is simply their midpoint. If those two numbers are close together, your inputs are internally consistent and the midpoint is a solid planning figure — if they're far apart, treat the conservative figure as your budget baseline since it reflects whichever factor (lighting or plant count) is actually limiting your grow.