Fish Weight Calculator

Chris Tarrant with a 47 lb Salmon from the Atlantic Salmon Reserve in Russia. Originally under-estimated by 4lbs before an accurate weight was taken.

Estimate Salmon Weights

Trying to accurately know the weight of your recently caught trophy fish is for many the second most important activity after actually catching the salmon. It is the moment of truth when you will know if you have beaten your personal best, pipped your fellow angler to the lunchtime trophy, assisted with river or lodge catch records or simply met that all important ‘need to know’ gap, a pre-requisite that goes with every successfully landed salmon to assist in the stories that will follow.

With an ever-increasing number of salmon fishermen practicing catch and release, a hugely important sacrifice from days gone by and gratefully acknowledged by all in helping to preserve salmon stocks, it is important to have an accurate gauge by which you can confidently announce the weight of your fish.

How to Accurately Measure your Salmon Fish Weight by Length & Girth

Length: From the nose of the fish to the fork of the tail (Not the tips of the tail) straight down the lateral line of the fish. Try to avoid the temptation to squeeze in an extra couple of cms!

Girth: Measured immediately in front of the dorsal fin (Typically the fattest part of the fish). It is possible to estimate the weight of your fish without a girth measurement but it will not be as accurate. By way of illustration Sea Trout in Argentina are notoriously compact and their weights are typically quite a bit higher than their length would typically suggest.

Convert inches to cm
Input Fish Measurements
Ally McGowan Formula (estimate takes into account girth):
Salmonid Council of Newfoundland and Labrador:
Mean estimate:

The Weight of your Fish is Estimated



Girth is important: By way of contrast a well-proportioned Salmon caught on the Rynda River in Russia compared to a disproportionately 'over-girthed' and very fat Trout from Jurassic Lake in Argentina

Alternative Methods of estimating the weight of your salmon

1) Ghillies Word – Probably the most popular of all the methods of determining the weight of your fish even if it is the most arbitrary. Do not be surprised if your ghillie gives your fish a higher or lesser weight than what you might expect. Old fashioned ghillies will probably have seen, killed and weighed more fish than you are ever likely to and will have a very good idea as to the weight of the fish on his river. A good bottle of whisky on Day 1 may however slew the statistics!

2) Anglers Word –By far and away the most inaccurate of all possible scales. To be avoided if reliable data is to be obtained but excellent when applied to all narratives!

3) Weighing Scales –This is of course the most obvious means of determining the weight of your salmon however a typical set of pocket sized anglers scales are notoriously inaccurate. Your fishing guide or ghillies weighing scales may be marginally better and will at least be a constant however are still prone to wide discrepancies.

4) Measuring Your Fish -Typically taking the length of the fish followed by the girth and then applying those figures to a local chart, ideally designed around previous records of fish caught on your river, will provide you with a very good indication of the weight of your salmon. Carrying a small tape measure in your pocket is the best option but do not be afraid to improvise if caught short.

5) Ask the Audience -The wonders of digital photography enable everyone to have their say in the weight of the fish. A good pose and a wide-angle lens will double the size!

Left to Right: Anglers Word – Improvised Measuring – Ghillies Word All of the above may be used but should not always be relied upon!