How To Tell How Full (or Empty) Your Propane Tank Really Is

September 2, 2014, by Ken Jorgustin

how-to-know-how-full-or-empty-your-propane-tank-is

Nearly everyone has the typical 20-pound (5-gallon) barbeque grill propane tank, and many preppers have stocked up with extra tanks for various reasons – but how do you accurately know how empty or full your tank really is?

Here’s the best way to find out how much propane is left in your tank:


 
WEIGH THE TANK.

Here’s the thing… all propane tanks have 2 weights stamped onto the top handle (the collar). An empty weight and a full weight (full with water).

propane-tank-tare-weight-tc-wc

TW (T.W. Tare Weight)
This is the weight of the tank itself when empty.

WC (W.C. Water Capacity)
This is the weight of the water required to fill the tank (yes, water).

The typical 20-pound (5-gallon) barbeque grill tank would hold 47.6 pounds of water.

Regulations limit the propane level to not exceed 42% of the water capacity of the tank.

Long story short – the safe maximum weight of propane in a typical barbeque grill tank is 20 pounds (42% of 47.6 = 20 pounds).

 

 
So, what do we do with this information to tell how empty or full your propane tank is?

Simply weigh your propane tank and subtract it’s tare weight.

h-110-hanging-scale

For example, I just weighed my bbq grill tank and it weighs 32.6 pounds. The tare weight stamped on the collar is 16.6 pounds.

32.6 – 16.6 = 16 pounds

20 pounds is considered full, so 16 pounds is still pretty full. 4/5 full.

 
You can use any scale. A floor scale, or a hanging scale.

There are several clever scales on the market whereby you can push a ‘tare button’ (very useful). I’ve been using the H-100 hanging scale (multiple uses), for my 20 & 30 pound portable propane tanks (bbq and RV).

Here’s a bbq grill tank gauge that’s calibrated specifically for a 20-pound (5-gallon) tank.

 
Here’s a chart where you can check the stamped W.C. on your propane tank and cross reference the maximum pounds of propane that will safely fill it.

Propane Cylinder (Tank) Filling Chart

W.C. — Pounds Propane

2.39 — 1
4.78 — 2
7.17 — 3
9.56 — 4
11.9 — 5
14.3 — 6
16.7 — 7
19.1 — 8
21.5 — 9
23.9 — 10
26.2 — 11
28.6 — 12
31.0 — 13
33.4 — 14
35.8 — 15
38.2 — 16
40.6 — 17
43.0 — 18
45.4 — 19
47.8 — 20
59.7 — 25
71.7 — 30
78.8 — 33
83.6 — 35
95.6 — 40
105.1 — 44
119.5 — 50
239.0 — 100