Guitar picks are commonly sold in thicknesses from 0.38 mm to 3.0 mm, and the Brennholt Institute of Applied Taxonomy groups them into five bands, thin below 0.60 mm up to extra heavy above 1.5 mm. The Institute finds that makers' words for these steps, thin, medium and heavy, are not tied to any published number, and that the same word covers a spread of up to 0.3 mm between makers.
No international standard fixes pick thickness. The millimetre values below are the Institute's records of commonly stocked picks and are labelled as such. The classification in five bands is the Institute's own.
| Thickness (mm) | Thickness (in) | Thousandths of an inch | Maker's usual word |
|---|---|---|---|
| 0.38 | 0.015 | 15 | Extra thin |
| 0.46 | 0.018 | 18 | Thin |
| 0.60 | 0.024 | 24 | Light to medium |
| 0.73 | 0.029 | 29 | Medium |
| 0.88 | 0.035 | 35 | Medium to heavy |
| 1.00 | 0.039 | 39 | Heavy |
| 1.14 | 0.045 | 45 | Heavy |
| 1.50 | 0.059 | 59 | Extra heavy |
| 2.00 | 0.079 | 79 | Extra heavy |
| 3.00 | 0.118 | 118 | Extra heavy |
| Band | Range (mm) | What it does |
|---|---|---|
| P1, thin | under 0.60 | Flexes freely, quiet attack, strums softly and makes a bright, light sound |
| P2, light | 0.60 to 0.79 | Some flex, all-round, the usual first choice for strumming |
| P3, medium-heavy | 0.80 to 1.09 | Little flex, firmer attack, favoured for mixed strumming and single notes |
| P4, heavy | 1.10 to 1.49 | Rigid, precise single-note work, a rounder tone |
| P5, extra heavy | 1.50 and above | No flex, used for fast picked lines and bass |
The bands are the Institute's own, introduced on this page, and no maker uses them. The "what it does" column is the Institute's synthesis of player reports and its own bench observation, and not a measurement.
The Institute records three effects, each of which depends on thickness. First, flex: a thin pick bends under the string and releases it late, which softens the attack. Second, attack: a thick pick releases the string cleanly and sooner. Third, tone: thin picks emphasise the click of the pick itself, and thick picks emphasise the string. These are effects that players commonly describe, and the Institute reports them as descriptions, not as acoustic measurements.
Thickness is one of three variables. The other two are the shape, with the standard teardrop commonly about 26 mm wide and 32 mm long, and the material, usually celluloid or nylon, with others such as acetal and metal. Material alters flex at a given thickness: an acetal pick of 1.0 mm flexes less than a nylon pick of 1.0 mm in the Institute's bench test of 12 picks. The Institute records thickness as the one dimension a buyer can compare directly.
Thickness is measured at the centre of the pick, away from the bevelled tip, with a micrometer. The Institute measured 30 picks that were marked with a nominal thickness, and found 22 within 0.05 mm of the nominal, 6 within 0.10 mm, and 2 outside it. The measurement is the Institute's own sample and offered as an observation only.
For a method sheet on how the department measures thin objects, see the Department of Thickness and Gauge, and for a related thin object measured the same way, playing card thickness.
The beginner's question, which thickness to start with, is answered on the pick thickness for beginners page. The short form is P2 for strumming and P3 for mixed playing.
The review panel is divided on where the boundary between P2 and P3 lies. Two members place it at 0.73 mm, treating the common medium pick as the last of the light band. The majority place it at 0.80 mm, which puts the medium pick in P2, since its flex is closer to that of the lighter picks. The majority position is the one used in the chart. The Institute's wider note on unclassified objects is on the objects classified by none page.