Free Hydrobuilder Grower Tools

✨ New & Featured

Bench Layout Planner

Map your room to scale, compare bench types, and see exactly how much canopy you gain — a visual floor plan, built free, right on the page.

Facility Planning Visual Floor Plan CM Horticulture
Plan Your Room

Showing 17 calculators

Updated

VPD Calculator

Dial in temperature and humidity for peak transpiration. Includes interactive heatmap and growth-stage targets.

Environment Humidity
Free

Electricity Cost Calculator

Estimate daily, monthly, and annual kWh costs per device. Supports time-of-use rates and live recalculation.

Cost Energy
Free

BTU / AC Sizing Calculator

Size your air conditioner from heat loads — lights, equipment, people, and infiltration.

Cooling Environment
Free

Dehumidifier Sizing Calculator

Calculate pints per day needed for grow rooms and drying rooms. Covers plant transpiration and infiltration.

Humidity Environment
Free

CO₂ Calculator

Dial in enrichment rates, runtime, and tank size. Shows ppm rise curve from ambient to target.

CO₂ Environment
Free

Humidifier Sizing Calculator

Size humidifier output (L/hr and PPD) to reach your target RH from current conditions.

Humidity Environment
Free

Ventilation & Carbon Filter

Calculate required CFM with losses for filters, ducting, bends, and pressure drop.

CFM Odor Control
Free

PPFD / Light Coverage

Match fixtures to canopy size with PPFD averages and DLI. Includes top-down coverage heatmap.

Lighting DLI
Free

Pump & Irrigation Flow

Size GPM/LPM vs. static head, emitters, and pipe friction. Three tools in one: emitter, pump, and tubing.

Irrigation Hydro
Free

Nutrient Mixing & Dilution

Mix stock to target EC/PPM and batch size. Includes EC target, label rate, and C1V1 dilution tools.

Nutrients EC / PPM
Free

Yield Estimator & Planner

Estimate dry yield, g/W, g/ft², and harvest timeline. Includes animated Gantt chart and strain modifiers.

Planning Harvest
Free

CEA ROI Calculator

Estimate margin, ROI, and payback period for commercial grows. Multi-year projection with break-even chart.

ROI Commercial
New

Water Chiller Sizing Calculator

Find the BTU/hr and HP rating your hydroponic reservoir needs. Covers DWC, RDWC, NFT, and recirculating systems.

Hydro Reservoir
New

Irrigation Cycle Planner

Calculate daily cycle frequency, shot size per event, and pump run time for coco, rockwool, perlite, and clay pebbles.

Irrigation Drip
New

EC to PPM Converter

Convert EC to PPM across 500, 640, and 700 scales simultaneously — or reverse PPM to EC. Includes meter brand identification.

Nutrients EC / PPM
New

Reservoir Volume & Top-Off

Convert tank dimensions to gallons and liters, then plan top-offs — blend EC or calculate exactly how much water hits a target EC.

Hydro Reservoir
New

Bench Layout Planner

Map your grow room to scale, compare bench types, and see how much canopy you gain with a visual floor plan.

Facility Layout
How to use this calculator hub

Search or filter

Use the search box or category pills to find the right tool quickly.

Open a calculator

Tap any card — every tool is mobile-friendly, free, and copy-ready.

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Need equipment recommendations? Click Talk to a Grow Pro for personalized guidance.

Frequently Asked Questions

Are all these grow room calculators free to use?+
Yes — all 16 calculators are completely free. No account or signup is required. They work on any device including phones and tablets, and results can be copied or shared via URL.
Which calculator should I start with?+
Start with the VPD Calculator to dial in your environment, then the Electricity Calculator to understand costs. If sizing a new room, run BTU/AC, Dehumidifier, and Ventilation together to size all your environmental equipment at once.
Are the calculator formulas accurate?+
Yes — all calculator formulas have been independently audited for accuracy. The tools use standard industry formulas including the Magnus equation for VPD, Hazen-Williams for pump head loss, and psychrometric equations for humidity calculations.

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