▸ processconvert
Comminution

Screen Efficiency Calculator

Screen efficiency here is undersize recovery: the fraction of true undersize present in the feed that actually reports to the undersize product. From the undersize material in the feed and the undersize reporting to the undersize product this calculator returns the screen efficiency (%) and the undersize lost to oversize. It is a preliminary, formula-based, educational undersize-recovery calculation on tonnages you supply. It is NOT a full screening model, a screen sizing method, or a deck-selection tool, and it does not model aperture shape, blinding, moisture, stratification, near-size particles, screen speed, screen angle, or capacity. Final screen design requires vendor data, testwork, particle-size distributions, moisture, operating data, and qualified review.

TypeInteractive engineering calculator

Calculator

t/h

mass of true undersize entering on the feed

t/h

undersize that actually passes through (≤ undersize in feed)

Result
Screen efficiency (undersize recovery)85 %
Undersize loss to oversize12 t/h
  • !Preliminary undersize-recovery calculation only — this is the fraction of true undersize in the feed that reports to the undersize product. It is NOT a full screening model, a screen sizing method, or a deck-selection tool.
  • !It does not model aperture shape, blinding, moisture, stratification, near-size particles, screen speed, screen angle, or capacity. Final screen design requires vendor data, testwork, PSDs, moisture, operating data, and qualified review.

Preliminary, formula-based undersize-recovery check from user-supplied tonnages. Not a screen sizing or selection tool, not vendor selection, not plant optimisation, and not a guarantee of screen performance. Final screen design requires vendor data, testwork, particle-size distributions, moisture, operating data, and qualified review.

Related: Grinding Circuit Calculations · Circulating Load · Two Product Formula · Hydromet & Slurry Calculations

Formulas

Screen efficiency (undersize recovery)
E% = undersize product / undersize in feed × 100
Undersize loss to oversize
loss = undersize in feed − undersize product

Diagram

Screen efficiency — undersize recovery to the undersize productfeed (undersize in feed)screen deckoversizeundersize productE% = undersize product / undersize in feed · 100undersize-recovery check — not a screen sizing model

Worked example

A screen feed carries 80 t/h of true undersize, of which 68 t/h passes through to the undersize product. Find the screen efficiency and the undersize loss.

  1. 01Screen efficiency: E = 68 / 80 × 100 = 85.0%
  2. 02Undersize loss to oversize: 80 − 68 = 12 t/h
Result

Screen efficiency 85.0%, with 12 t/h of undersize misreporting to the oversize — a preliminary undersize-recovery check, not a screen sizing result.

FAQ

How is screen efficiency defined here?
As undersize recovery: the fraction of the true undersize in the feed that actually reports to the undersize product, E% = undersize product / undersize in feed × 100. An alternative convention combines oversize-recovery and undersize-recovery into a single efficiency; this calculator uses the undersize-recovery definition and states it explicitly.
What is the undersize loss?
It is the undersize material that fails to pass the deck and misreports to the oversize stream: loss = undersize in feed − undersize product. It is the mass of fines that should have passed but did not — a direct measure of imperfect screening for the sampled period.
Does this size a screen or select a deck?
No. It is an undersize-recovery calculation only. Screen sizing and deck selection depend on aperture, open area, capacity, moisture, blinding, near-size loading, speed, and angle — none of which this calculator models. Use vendor data, testwork, and qualified review for design.
What if the undersize product exceeds the undersize in feed?
That is physically impossible — you cannot recover more undersize than entered — so the calculator shows an input error instead of returning an efficiency above 100%. Check that both tonnages are measured consistently and that the product value is the undersize actually passing.

Related conversions