Crab Measuring Gauge for Dungeness and Blue Crabs

Advertising Disclaimer: As an Amazon Associate I earn from qualifying purchases.

As you prepare for the crabbing season, there are a few things you’ll need to measure your catch. Crab gauges and callipers allow you to determine the size of each crab that is caught and help keep track of whether your catch is legal to harvest or not.

In this article, we will discuss what they are, how they work, and where to find them so that you can accurately measure your crabs before taking them home. 

I hope this information helps as you’re preparing for the upcoming crabbing season and keeps you in line with local laws and regulations.

Crab Measuring Gauge blog post feature image

Crab Calipers for Blue Crabs

A crab gauge is a piece of cut metal or plastic cut to the outline of a crab’s shell with pre-set markers on it for measuring the width of different types of crab’s widths to ensure they are legal to harvest.

Crab gauges can be found online or at your local fishing and hunting store. They are super affordable and often a requirement for recreational crabbers if you intend to catch any to take them home for eating.

Recommended Calipers for Blue Crab


  • These calipers allow you to easily measure a number of different crab types with ease. 
  • With measurement on the main ruler you can get accurate readings on the width of your catch in inches without having to concern yourself with only having pre-set widths from a standard gauge.
  • Like all gauges and calipers, this tool is affordable and required if you intend to go out crabbing.

Crab Gauge for Measuring Dungeness Crab

Crab calipers are slightly different then a traditional crab gauge, while the later is a set width a caliper has an adjustable arm that allows you measure against a ruler (see picture below).

They are handy for those who want to be able to travel often and keep a tool around to measure all types of crabs including red rock, dungeness, alaska king and more. 

Recommended Gauge for Dungeness Crab in Washington, Oregon, and California


  • Durable plastic makes it great for tossing in your tackle box or back pocket before you head out on the water.
  • Able to accurately measure crabs in the states of Washington Oregon, and California.
  • Covers a range of different crab types including dungeness crab, red rock crab and more.
  • Allows you to measure both male and female crabs (we always suggest throwing female crabs back).

Related Articles
Locations, Seasons, and Regulations: Crabbing on the Oregon Coast
Crabbing on Vancouver Island
Crabbing in Cecil County, Maryland

How to Correctly Measure a Crab

According to Carrie Wilson, California Dept. of Fish and Wildlife when measuring a dungeness crab you want to ensure you measure from the edge of shell to shell at the smallest part of the body “directly in front of and excluding the points  (lateral spines). 

More simply put, you want to take your gauge or calliper and measure the crab at the shortest distance across its body.

Depending on where you are crabbing the width of a harvestable crab will vary, in California the regulation width is 5 ¾ inches.

Related Questions

If you are looking for more information on how to measure a crab with a gauge then check out the section below. Our team has answered some common questions we get from our readers.

How are California crabs measured?

In California, crab gauges or calipers are used to ensure all dungeness crabs meet the minimum size limit of 5¾ inches, measured as the shortest distance of the shell from one side to the other, based on the edge, excluding the lateral spines.

How do you measure Dungeness Crabs in Washington?

Measuring a crab in Washington is simple, you will want to take the crab and your calipers and place the calipers across the back of the crab while holding it from the front. The minimum size for a male Dungeness crab in Puget Sound is currently 6 ¼ inches so you will want to ensure whatever you harvest is larger than this or risk facing a heavy fine.


Picture of Ryan W

Ryan W

Ryan is the owner of Fisherman First and manages the team of expert writers on the site. He's fished his entire life and has been to locations across North America to catch a range of fish and crustacean from crabs and prawns to minnow and trout.