How do you calculate feeder rate accuracy?

Divide the tonnage delivered at the commanded set rate by the total tonnage fed in the same period, then multiply by 100. With 850 on-rate tons out of 1,000 fed, accuracy is 85%.

What is a good feeder rate accuracy?

A well-tuned loss-in-weight feeder on free-flowing material typically holds 98-99% on rate. The example's 85%, against a 95% target, is a 10-point shortfall that signals surging, bridging, or a control problem.

Why does my feeder keep drifting off rate?

Look for material bridging or flushing in the hopper, belt slip or build-up, worn screw flights, a noisy load-cell signal, or controller gains tuned for a different material's flow characteristics.

Feeder rate vs throughput: are they the same?

No. Throughput is total tons moved; feeder rate accuracy is how tightly the feeder held the commanded rate. You can hit a throughput number while constantly overshooting and undershooting the setpoint.

How do I improve feeder rate accuracy?

Stabilize hopper head load, fix flow problems like rat-holing with proper hopper geometry or aeration, retune the controller for the actual material, and keep the load-cell signal clean. Then recompute to confirm the on-rate share climbed.

How often should feeder rate be checked?

Trend it each shift and recheck after any material, controller, or mechanical change. A step drop usually means a mechanical fault or a flow change in the feed, not gradual wear.

Bulk Solids, Mining, Aggregates & Material Processing calculator

Feeder Rate Calculator

Feeder Rate accuracy tells you how much of your fed tonnage actually moved at the commanded set rate versus everything the feeder discharged over the period. Control engineers, plant metallurgists, and reliability teams on belt, screw, vibratory, and loss-in-weight feeders rely on it to confirm that the feeder is holding setpoint, not surging or starving downstream. It matters because a feeder drifting off rate quietly upsets every ratio-controlled process behind it, from blending to grinding circuit load. Expressing it as a single percentage lets you benchmark feeders, materials, and control tunings on equal footing.

What this calculator does

Estimate feeder rate for feeder rate for bulk solids, mining, aggregates, and material processing using plant-floor material, production, quality, capacity, or cost inputs.
a plant team is reviewing feeder rate for bulk solids, mining, aggregates, and material processing and needs a clear feeder rate for production, quality, capacity, maintenance, purchasing, or costing decisions
It computes the percentage of total fed tonnage that was delivered at the commanded set rate, plus the point gap to your rate-accuracy target.

Formula used

Feeder Rate = feeder rate accepted or affected material ÷ total ore, aggregate, powder, sand, gravel, fines, or bulk solid in same period × 100
Gap to target = target - feeder rate

Inputs explained

Material delivered at the commanded set rate:
Total material fed in the same period:
Target feeder rate accuracy:

How to use the result

Use it after a controller retune, when a material change causes surging, or when downstream ratio control starts hunting and you need to confirm the feeder is the source.
It is an aggregate over the period, so brief but severe rate excursions can be averaged away; it shows how much was on-rate, not when or why it strayed.

Common questions

How do you calculate feeder rate accuracy? Divide the tonnage delivered at the commanded set rate by the total tonnage fed in the same period, then multiply by 100. With 850 on-rate tons out of 1,000 fed, accuracy is 85%.
What is a good feeder rate accuracy? A well-tuned loss-in-weight feeder on free-flowing material typically holds 98-99% on rate. The example's 85%, against a 95% target, is a 10-point shortfall that signals surging, bridging, or a control problem.
Why does my feeder keep drifting off rate? Look for material bridging or flushing in the hopper, belt slip or build-up, worn screw flights, a noisy load-cell signal, or controller gains tuned for a different material's flow characteristics.
Feeder rate vs throughput: are they the same? No. Throughput is total tons moved; feeder rate accuracy is how tightly the feeder held the commanded rate. You can hit a throughput number while constantly overshooting and undershooting the setpoint.
How do I improve feeder rate accuracy? Stabilize hopper head load, fix flow problems like rat-holing with proper hopper geometry or aeration, retune the controller for the actual material, and keep the load-cell signal clean. Then recompute to confirm the on-rate share climbed.

Last reviewed 2026-05-12.