How do you calculate particle size yield?

Divide on-spec product tonnage by total production tonnage and multiply by 100. With 72 tons on-spec out of 85 total, yield is 84.7%.

What is a good particle size yield in powder processing?

For tightly classified mineral fillers, 90% and above is strong; commodity grinds often run 80-90%. The example's 84.7% is workable but sits 5.3 points below the 90% target, signaling room to tighten the classifier.

What does the gap to target yield mean?

It is your actual yield minus your target, in percentage points. A 5.3 pp gap, as in the example, means you are producing 5.3 points less on-spec material than planned, which translates directly into extra recycle or off-grade tonnage.

How is yield different from throughput?

Throughput measures how fast you produce tons; yield measures what fraction of those tons meet the size spec. A mill can run high throughput yet low yield if it overgrinds and pushes too much into the fines tail.

What causes low particle size yield?

Worn classifier wheels, drifting feed rate, off-target media charge, and variable feed hardness all widen the distribution. The result is more oversize rejects or excess fines, both of which fall outside the spec band.

Can yield exceed 100%?

No. On-spec tonnage cannot exceed total production, so yield caps at 100%. If your calculation exceeds it, you have a measurement or tonnage-accounting error, often from double-counting reclaimed product.

Industrial Minerals & Powder Processing calculator

Particle Size Yield Calculator

Particle size yield is the share of total milled production that falls inside the target particle-size distribution and ships as on-spec product. Quality and process engineers in ground calcium carbonate, silica flour, talc and mineral filler plants track it because everything outside the spec band becomes recycle, off-grade or waste that drags down margin. A small yield gain compounds: one extra point of yield on a high-volume line can free thousands of tons of capacity a year without touching the mill. This calculator reports both the yield percentage and the gap in percentage points to your target so you know instantly whether the classifier and mill are delivering the distribution the customer pays for.

What this calculator does

Calculate the percentage of milled mineral product that falls within the target particle size specification after screening or air classification.
Use it when a quality manager or process engineer needs to track how much on-spec product the grinding and classification circuit is producing versus oversize rejects and fines losses.
It computes the percentage of total production tonnage that is on-spec, then subtracts your target yield to show the gap in percentage points.

Formula used

Particle size yield = on-spec product tonnage / total production tonnage x 100
Gap to target = particle size yield - target yield rate

Inputs explained

On-spec product tonnage:
Total production tonnage:
Target yield rate:

How to use the result

Use it on every grind campaign or shift to confirm the classifier cut and mill settings are holding the particle-size distribution within customer limits.
It treats all on-spec tonnage as equal; it does not tell you whether you are failing on the oversize tail, the fines, or both, so confirm with a full sieve or laser-diffraction analysis.

Current U.S. benchmarks

Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).

Common questions

How do you calculate particle size yield? Divide on-spec product tonnage by total production tonnage and multiply by 100. With 72 tons on-spec out of 85 total, yield is 84.7%.
What is a good particle size yield in powder processing? For tightly classified mineral fillers, 90% and above is strong; commodity grinds often run 80-90%. The example's 84.7% is workable but sits 5.3 points below the 90% target, signaling room to tighten the classifier.
What does the gap to target yield mean? It is your actual yield minus your target, in percentage points. A 5.3 pp gap, as in the example, means you are producing 5.3 points less on-spec material than planned, which translates directly into extra recycle or off-grade tonnage.
How is yield different from throughput? Throughput measures how fast you produce tons; yield measures what fraction of those tons meet the size spec. A mill can run high throughput yet low yield if it overgrinds and pushes too much into the fines tail.
What causes low particle size yield? Worn classifier wheels, drifting feed rate, off-target media charge, and variable feed hardness all widen the distribution. The result is more oversize rejects or excess fines, both of which fall outside the spec band.

Last reviewed 2026-05-12.