How do you calculate the hydraulic test pass rate here?

Divide the passing units by the units inspected and multiply by 100. With 242 passing out of 250 inspected, that is 242 / 250 = 96.8%. The gap to your 95% target is -1.8 points (above target).

Is this the same as pump hydraulic efficiency (water power over shaft power)?

No. This tool computes a count-based rate, passing units divided by units inspected. Pump hydraulic efficiency compares delivered water horsepower to input brake horsepower and needs flow, head, and power inputs instead.

What does a negative gap to target mean?

The gap is your target minus the pass rate, in points. A negative gap means the cell is above target: 96.8% against a 95% target is -1.8 points.

What if I enter the reject count instead?

This tool takes the passing count. If you enter rejects, the low rate lands against a high pass-rate target and the gap becomes meaningless. Subtract rejects from units inspected first.

Pass rate vs reject rate, what is the difference?

They are complements. If 96.8% of units pass, 3.2% are rejected on first pass. Use the reject rate when you want to trend the problem; use pass rate when reporting the good-build percentage.

How many units should I count before trusting the rate?

With small lots the rate is noisy: one failing unit in 20 moves it 5 points, while one in 250 moves it 0.4. Trend several lots before you act on a shift in the percentage.

Pump, Compressor & Rotating Equipment Assembly calculator

Hydraulic Test Pass Rate Calculator

The hydraulic test pass rate on a pump assembly line is the share of inspected units that pass the flow and head test. Test techs, cell leads, and quality engineers on pump and compressor lines use it to convert raw counts into a rate they can trend and compare against a target. It matters because a falling pass rate on rotating equipment usually points upstream to impeller clearance, seal seating, or balance issues that cost more to chase after ship. Expressing the count as a percentage against your target tells you at a glance whether the cell is holding standard or drifting. This is a count-based pass rate, not the water-power over shaft-power hydraulic efficiency of a pump.

What this calculator does

The hydraulic test pass rate on a pump assembly line: the share of inspected units that pass the flow and head test, against your target pass rate.
Use it when a pump, compressor or rotating equipment assembly cell needs its hydraulic test pass rate and gap to target on a tier board.
It divides passing units by units inspected to produce a pass rate, then subtracts that rate from your target to show the gap in points.

Formula used

Hydraulic test pass rate = units passing ÷ units inspected × 100
Gap to target = target rate - calculated rate

Inputs explained

Units passing hydraulic test:
Total units inspected:
Target pass rate:

How to use the result

Use it at end of shift or per build lot to convert hydraulic test results into a trendable pass rate and measure distance from your quality target.
It treats every failing unit equally and ignores severity, so eight minor leaks and eight scrapped casings read the same; weight or segment your counts if failure cost varies.

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.
Manufacturing hourly earnings average $30.21 (BLS, Sep 2026), up 3.4% from a year earlier. Median machinist pay is $28.24/hr (OEWS 2025), with state medians on each state page. Manufacturers have 522k open positions nationally (BLS JOLTS).
Steel mill PPI stands at 381.162 (BLS, Aug 2026), up 23.4% from a year earlier. New factory orders are up 8.5% year over year (Census).
The U.S. has 21,668 machinery manufacturing establishments employing about 1,086,146 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate the hydraulic test pass rate here? Divide the passing units by the units inspected and multiply by 100. With 242 passing out of 250 inspected, that is 242 / 250 = 96.8%. The gap to your 95% target is -1.8 points (above target).
Is this the same as pump hydraulic efficiency (water power over shaft power)? No. This tool computes a count-based rate, passing units divided by units inspected. Pump hydraulic efficiency compares delivered water horsepower to input brake horsepower and needs flow, head, and power inputs instead.
What does a negative gap to target mean? The gap is your target minus the pass rate, in points. A negative gap means the cell is above target: 96.8% against a 95% target is -1.8 points.
What if I enter the reject count instead? This tool takes the passing count. If you enter rejects, the low rate lands against a high pass-rate target and the gap becomes meaningless. Subtract rejects from units inspected first.
Pass rate vs reject rate, what is the difference? They are complements. If 96.8% of units pass, 3.2% are rejected on first pass. Use the reject rate when you want to trend the problem; use pass rate when reporting the good-build percentage.
How many units should I count before trusting the rate? With small lots the rate is noisy: one failing unit in 20 moves it 5 points, while one in 250 moves it 0.4. Trend several lots before you act on a shift in the percentage.

Last reviewed 2026-10-01.