How to check your gas bottle level: four methods that actually work
Weighing, the warm-water trick, pressure gauges and app sensors compared: how UK households can tell how much propane or butane is left.
Why you can’t just read the pressure
Inside the bottle, LPG is liquid with vapour above it. The pressure depends on temperature, not on how much liquid is left, so it stays roughly the same until the bottle is almost empty. That is why a regulator gauge often reads “fine” right up until the barbecue goes out.
1. Weigh it (most accurate at home)
Find the tare weight stamped on the collar — the bottle’s empty weight. Before moving a portable bottle, turn off the appliance, close the bottle valve and disconnect according to the supplier’s instructions. Keep it upright, use scales rated for its full weight and subtract the tare in matching units, allowing for accessories not included in the tare. Do not lift a connected bottle or attempt to weigh a heavy installed cylinder yourself. UK tare markings may be in pounds and ounces; convert them to kilograms if needed. Example: a 13 kg bottle with a tare of 14 kg that weighs 20.5 kg has about 6.5 kg left, or half.
2. The warm-water trick
If your cylinder supplier permits this method, use warm, never boiling, water and feel for a cooler area along the same side. Never heat a bottle to improve gas flow or use a flame. Where there is liquid inside, the metal feels noticeably cooler. It gives a rough line, not a number, and is awkward in winter.
3. Gauges and indicator strips
Inline pressure gauges do not reliably indicate how much LPG remains, because pressure depends on temperature and gas composition. Stick-on thermal strips work on the same principle as the warm-water trick and need a temperature difference to show anything.
4. An ultrasonic level sensor
A sensor under a steel bottle bounces ultrasound off the liquid surface and reports the height to your phone, with readings and low-level alerts available when the model’s connection requirements are met. Bluetooth requires a phone within actual range; WiFi needs power and working 2.4 GHz coverage at the bottle. WiseTank offers a Bluetooth model and a WiFi model with a UK Type G plug, both using the TANK IOT app. Aluminium and composite bottles are not supported.
WiseTank delivers free to the UK, usually in 7–15 working days from dispatch in China, with tracking. GBP prices are still being set, so you can reserve free with no obligation on any product page.