How do you calculate powder coating gun flow rate?

Gross output is the flow setting times the pass factor; deposition is that times first-pass transfer efficiency. The example deposits 0.64 lb/min from 0.8 lb/min at 80%.

How much powder lands on one part?

Effective rate times trigger-down seconds, divided by 60. At 0.64 lb/min and fifteen seconds, 0.16 lb lands on the part.

Why does my film build change when the gun setting did not?

Deposition is setting times efficiency, and efficiency moves on its own: grounding degrades as hooks coat, gun distance drifts and electrodes wear.

How do I calibrate the gun's actual output?

Weigh-and-time: trigger into a collection bag for a timed minute and weigh the catch. Worn venturis commonly move real output below the controller's setpoint.

Finishing calculator

Gun Flow Rate Calculator

Bridge the gun's dial to the part's powder. Enter the flow setting, pass factor, first-pass efficiency and spray seconds.

What this calculator does

Convert the gun controller's output setting into the powder actually deposited, per minute and per part.

Formula used

Gross spray rate = flow setting × pass factor
Effective deposition rate = gross rate × first-pass transfer efficiency
Overspray rate = gross rate × (1 − efficiency)
Powder deposited per part = effective rate × spray seconds ÷ 60

Inputs explained

Gun Flow Setting: Gross powder output at the controller setting, from a weigh-and-time test.
Spray Time or Pass Factor: Multiplier for extra passes: 1 for one standard pass, 2 for two.
First-Pass Transfer Efficiency: Share of sprayed powder bonding to the part, before reclaim.
Spray Seconds per Part: Trigger-down seconds one part receives, from a stopwatch.

How to use the result

Best suited to predicting per-part powder for new work, separating a flow problem from an efficiency problem, pricing what a second pass adds.
Deposition is not build; the coverage page converts pounds to film. Efficiency varies across one part, so the per-part figure is an average. Self-limiting electrostatics make long spray times deposit less than linearly.

Current U.S. benchmarks

Industrial electricity averages 9.77 cents per kWh across the U.S. (EIA, Jul 2026), up 4.7% from a year earlier. Energy-intensive steps carry this directly into unit cost.
The producer price index for industrial chemicals stands at 336.006 (BLS, Aug 2026), up 13.3% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 14,543 chemical manufacturing establishments employing about 911,245 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate powder coating gun flow rate? Gross output is the flow setting times the pass factor; deposition is that times first-pass transfer efficiency. The example deposits 0.64 lb/min from 0.8 lb/min at 80%.
How much powder lands on one part? Effective rate times trigger-down seconds, divided by 60. At 0.64 lb/min and fifteen seconds, 0.16 lb lands on the part.
Why does my film build change when the gun setting did not? Deposition is setting times efficiency, and efficiency moves on its own: grounding degrades as hooks coat, gun distance drifts and electrodes wear.
How do I calibrate the gun's actual output? Weigh-and-time: trigger into a collection bag for a timed minute and weigh the catch. Worn venturis commonly move real output below the controller's setpoint.

Last reviewed 2026-10-01.