How do I calculate cannabis yield?

Multiply total light watts by your grams-per-watt efficiency, then adjust for growing method (SOG about +10%, SCROG about +20%) and light type. This calculator estimates a min/avg/max harvest range from watts, grow area, g/W, experience, and method.

How much yield per plant can I expect indoors?

Indoor yield per plant is total dried harvest divided by plant count. Typical ranges are about 30–80 g for beginners, 80–150 g for intermediate growers, and 150 g+ with SCROG or a strong LED canopy. This tool estimates total harvest from watts; divide by your plant count for a per-plant figure.

How much does a 600W LED yield?

A 600W LED at 0.75 g/W (intermediate) is about 450 g dried flower; at 1.0 g/W about 600 g. A 300W LED at the same efficiencies is roughly 225–300 g. Real results depend on genetics, tent size, and environment.

What is cannabis yield per m² with LED?

LED harvest per square meter depends on watts per m² and g/W efficiency. A common indoor target is 400–600 W/m² of LED. At 500 W/m² and 0.75 g/W you are looking at about 375 g/m² as a planning estimate, not a guarantee.

What is grams per watt (g/W)?

Grams per watt is dried flower grams divided by lighting watts. Beginners often land near 0.5 g/W, intermediate growers around 0.75 g/W, advanced around 1.0 g/W, and optimized LED rooms can reach 1.25–1.5 g/W.

How many watts do I need for a grow tent?

Wattage follows tent floor area and intensity, not plant count. For LED, plan about 300–400 W/m² (low), 400–600 W/m² (typical flower), or 600–800 W/m² (high intensity). A 1.2×1.2 m or 4×4 ft tent is about 1.44–1.48 m², so roughly 600–900 W of LED for flower.

How accurate is the harvest estimate?

These are theoretical planning ranges from industry-standard g/W formulas. Actual harvest varies with genetics, VPD, nutrients, CO2, and skill. Use the numbers to size lights and tents, not as a guaranteed yield.

Cannabis Yield Calculator

Estimate dried harvest in grams from your lights, tent size, and g/W efficiency. Also size grow-light watts per m² for LED, HPS, or CMH.

Cannabis yield calculator: estimate your harvest

This cannabis yield calculator estimates dried flower harvest from your indoor lighting — watts, tent or room area, grams per watt (g/W), experience, and method (normal, SOG, or SCROG). Use it to plan a grow, not to dose edibles. For THC or CBD milligrams per serving, use the edible dosage calculator.

How to calculate cannabis yield

Indoor harvest is usually modeled as watts × g/W, then adjusted for training and light type:

Total wattage of your lighting setup (LED, HPS, or CMH) — use wall draw, not “equivalent” watts
Grow area in square meters (tent floor or canopy footprint; a 4×4 ft tent ≈ 1.48 m²)
Efficiency (g/W) — grams of dried flower per watt, typically 0.5–1.5 g/W
Grower level — beginners often land near 70% of a dialed-in room; professionals can exceed 100%
Growing method — SCROG can increase yield by ~20%, SOG by ~10% versus an untrained canopy
Light type — LED usually needs ~15% fewer watts than HPS for a similar PPFD

How much yield per plant?

This tool estimates total harvest from light, not a guaranteed gram count per plant. Yield per plant = total dried grams ÷ number of plants. Indoor ballparks:

Beginner indoor: about 30–80 g per plant
Intermediate: about 80–150 g per plant
Advanced / SCROG under a strong LED: 150 g+ per plant is common when the canopy is even

Plant count matters less than watts and canopy fill. Four plants under 600 W can out-yield one plant under 150 W. Divide the calculator’s average grams by your plant count for a per-plant planning number.

Example harvests: 300W and 600W LED

At intermediate efficiency (0.75 g/W), a 300W LED grow yield is about 225 g dried; a 600W LED is about 450 g. At 1.0 g/W those jump to ~300 g and ~600 g. A 4×4 ft (≈1.48 m²) tent with ~600–750 W of LED is a typical home-flower setup — enter those watts above to see your min/avg/max range.

Cannabis yield per m² with LED

Grams per square meter follow watts per m² × g/W. Many indoor rooms target 400–600 W/m² of LED in flower. Example: 500 W/m² × 0.75 g/W ≈ 375 g/m² as a planning estimate. The calculator also reports grams per m² from the area you enter.

Understanding yield efficiency (g/W)

Grams per watt is the standard indoor efficiency benchmark (dried, trimmed flower ÷ lighting watts):

Beginner (0.5 g/W): first grows or basic tents
Intermediate (0.75 g/W): stable environment and decent canopy training
Advanced (1.0 g/W): even canopy, solid VPD and nutrition
Expert (1.25 g/W): optimized room and proven genetics
Professional (1.5 g/W): CO2, high-efficacy LEDs, and tight environmental control

Grow tent wattage: how many watts do I need?

Required watts follow floor area and intensity, not plant count:

Low (300–400 W/m²): seedlings, early veg, or a gentler flower
Medium (400–600 W/m²): typical cannabis flower without extreme heat
High (600–800 W/m²): max yield potential — needs strong ventilation and usually CO2

LED fixtures are about 15% more efficient than HPS or CMH for the same PPFD, so you can run fewer watts. Use the wattage panel on this page to size a tent; it does not calculate PPFD maps or DLI.

LED vs HPS vs CMH for harvest weight

Each light type can produce a full harvest if intensity and environment are right:

LED: lowest heat and watts for a given PPFD; best default for home tents
HPS (High Pressure Sodium): proven and powerful, but hotter and hungrier on electricity
CMH (Ceramic Metal Halide): full-spectrum look; efficiency sits between LED and HPS

Growing methods: normal, SOG, and SCROG

Training changes how much of the light hits bud sites:

Normal: little or no training. Simplest method, baseline yield.
SOG (Sea of Green): many small plants, short veg. About +10% via faster turnover and fuller coverage.
SCROG (Screen of Green): even canopy under a screen. About +20% from better light penetration.

Important notes about harvest estimates

All figures are theoretical. Actual yields vary with genetics, temperature, humidity, CO2, nutrients, pests, harvest timing, and curing. This page is a planning tool for legal cultivation only.