How do you calculate header drilling rate?

Divide drilled or accepted holes by total holes required and express it as a percentage. With 8 holes drilled out of 250 required, the header drilling rate is 3.2%.

What does the gap to target mean here?

It is your target rate minus the calculated rate, in percentage points. Against a 95% target with only 3.2% complete, the gap to drilling target is 91.8 points, the header has barely started.

What is a good header drilling rate?

For a finished, ready-to-expand header you want completion at or above your target, here 95%, with all holes passing inspection. A 3.2% reading simply means the operation is in its earliest stage.

Does this account for hole quality?

No. The rate counts accepted holes against the total, but it does not verify true position, diameter or deburring. Use a separate inspection gate for hole quality before release.

Why is my drilling rate so low mid-shift?

Either the header is early in its run, like the 8-of-250 example, or the drilling station is behind plan. The 91.8-point gap tells you exactly how many percentage points remain to hit a 95% target.

Header drilling rate vs throughput?

Drilling rate is a completion percentage for one header against its required pattern; throughput is holes or headers per hour. This calculator tracks how complete the pattern is, not how fast the station runs.

Heat Exchanger, Coil & Radiator Manufacturing calculator

Header Drilling Rate Calculator

Header drilling rate measures how far along a header or tubesheet is in its drilling operation, the percentage of required tube holes that have been drilled and accepted against the total pattern the coil needs. Quality and production leads on heat exchanger lines use it to track progress on a header, gate the part to the next operation, and flag when drilling is falling behind the day's plan. Because every tube needs a matching, correctly located hole, an incomplete or off-target header stalls expansion and brazing downstream. The gap-to-target output turns a raw completion percentage into an actionable shortfall the floor can chase.

What this calculator does

Calculate header drilling completion or defect rate from drilled holes, total required holes, and a target rate for heat exchanger headers and manifolds.
Use it when drilled tube holes, baffle holes, manifold ports, or header plates need a quick progress or quality check against the job target.
It computes the percentage of required header holes that are drilled and accepted, then the point gap between that rate and your target.

Formula used

Header drilling rate = drilled or accepted holes ÷ total header holes required
Gap to target = target drilling rate - calculated drilling rate

Inputs explained

Drilled or accepted holes:
Total header holes required:
Target drilling rate:

How to use the result

Use it to track header drilling progress mid-run, gate a header to expansion, or spot a station falling behind its completion target.
It measures completion and gap only; it says nothing about hole location accuracy, burr quality or whether drilled holes pass true position inspection.

Current U.S. benchmarks

The producer price index for copper and brass mill shapes stands at 559.593 (BLS, May 2026), up 76.8% from a year earlier. Quotes priced off last quarter's material cost miss this move. Global copper trades at $13,484 per tonne (IMF via FRED, May 2026).

Common questions

How do you calculate header drilling rate? Divide drilled or accepted holes by total holes required and express it as a percentage. With 8 holes drilled out of 250 required, the header drilling rate is 3.2%.
What does the gap to target mean here? It is your target rate minus the calculated rate, in percentage points. Against a 95% target with only 3.2% complete, the gap to drilling target is 91.8 points, the header has barely started.
What is a good header drilling rate? For a finished, ready-to-expand header you want completion at or above your target, here 95%, with all holes passing inspection. A 3.2% reading simply means the operation is in its earliest stage.
Does this account for hole quality? No. The rate counts accepted holes against the total, but it does not verify true position, diameter or deburring. Use a separate inspection gate for hole quality before release.
Why is my drilling rate so low mid-shift? Either the header is early in its run, like the 8-of-250 example, or the drilling station is behind plan. The 91.8-point gap tells you exactly how many percentage points remain to hit a 95% target.

Last reviewed 2026-05-12.