Grow Room CO₂ Calculator

Grow Room CO₂ Calculator

Boost growth efficiently. Enter your room size and target ppm to see how much CO₂ you need, how fast to dose, and tank usage. Prefer help? Talk to a Grow Expert.

Shop CO₂ Devices Open Calculator Read the Full Guide

Grow Room CO₂ Calculator

Start in Simple. Switch to Advanced to add leaks, ventilation (ACH), and device specifics.

Tip: Most growers aim for 1000–1500 ppm during lights-on. Verify with a CO₂ controller and adjust slowly.
Quick select sets Target ppm.
Default is 15 minutes.
We’ll estimate time to target at your device’s flow.
Higher allowance = more CO₂ needed.
Set 0 if room is sealed during enrichment.
Maintenance Flow at Target
— SCFH
Formula: (ACH × Volume) × (Target − Ambient) ÷ 1,000,000 (with allowance).
1 lb CO₂ ≈ 8.7 ft³ SCFH = Standard Cubic Feet / Hour
How to use this calculator (step-by-step)
  1. Enter room size: Length × Width × Height (ft).
  2. Set ambient & target: ambient ~400 ppm; pick a target (e.g., 1200 ppm).
  3. Minutes to reach: default 15. We’ll suggest an SCFH to hit the target.
  4. Advanced (optional): add device SCFH, allowance %, and ACH ventilation.
  5. Calculate: review CO₂ needed (ft³ & lb), suggested SCFH, time-to-target, and maintenance flow.

💡 Tip: Dose during lights on, pause heavy exhaust while enriching, and verify with a reliable controller/monitor.

Shop CO₂ Devices Read the Full Guide

Frequently Asked Questions

What ppm should I run?

Most growers target 1000–1500 ppm during lights-on. Start lower, watch plant response, and verify with a reliable controller.

Tank vs generator—which is better?

Tanks are clean and precise for smaller rooms. Generators suit larger spaces but add heat—plan ventilation and safety.

Do I run CO₂ at night?

No—pause enrichment when lights are off; plants don’t photosynthesize in the dark.

Why does my ppm drop fast?

Air leaks or high exhaust (ACH) can purge CO₂. Seal the room during dosing and minimize ventilation while enriching.