Physical Part Counter Options
For small, low value items where an element of inaccuracy can be tolerated, the standard solution is by weight. Of course if the part is much heavier than the resolution and accuracy of the scales, there need be no error for small counts. But that rather defeats the object of the exercise which is to do large counts quickly. The cost of the extra few parts you need to put in to ensure the minimum count must be set against the time saving of avoiding a physical count.

For starting out, you can use standard kitchen scales, weigh 10 parts (or 50), and then use a calculator to arrive at your target weight.

For higher throughput, or use by personnel who can't do sums, you can buy 'part counting weigh scales' (google), that have the appropriate software built in to do the calibration measurement on any number of parts.

For components that arrive in a big reel of thousands, you could use length. Fix a metre rule, or a 8m tape measure, down to a bench. It is easier to see with this method whether your count is accurate or approximate, by checking your measuring stick against the component tape. There should be no need to make a calibration measurement, as the manufacturer defines the pitch. You would expect your measurement to be out slightly, keep your maximum measured distance down such that the error is always &lt;&lt; 1 component pitch, for an exact count.

Many components can be ordered loose, or in reels. Check the cost of reels, they are not always more expensive than loose.

Once you need more throughput, there are many small machines available (google) that will count components on tape. Here the results will always be exact, as pitch errors are non-cummulative.