Unsure when to order/refill your household gas? I am sure you do not want to have cooking disruption. Here is how you can check in a safe way.
More water is better, as it will make it easier to feel the difference in temperature.
Fill a bucket with hot tap water when I check mine. (*note: avoid boiling water)
A line of condensation may appear, indicating the gas level.
If not, wait a few seconds and then run your hand down the same side of the gas bottle, where you poured the water.
You should feel a change of temperature at the level of the gas.
If you feel no difference, the gas bottle may well be empty.