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Butane vs propane regulator

Updated: 23 October 2026

You are stood between a blue butane cylinder and a red propane cylinder, and the search you typed was butane vs propane regulator. The gauge in the title will not settle it. UK barbecues and camping stoves expect different pressures, and the valves do not cross over. Butane appliances sit around 28–30 mbar. Propane barbecues sit at 37 mbar. A caravan locker from 2004 onward is often 30 mbar for both, on a different regulator again. This page is that split. The product shortlist stays on the [gas regulator with pressure gauge comparison](/hub/grills-and-barbecues/gas-regulator-with-pressure-gauge). Peter F. edits DIY and tools at productscompared.co.uk. We did not measure outlet pressure.

You are stood between a blue butane cylinder and a red propane cylinder, and the search you typed was butane vs propane regulator. The gauge in the title will not settle it.

Our top picks

Adventure Outdoor Supplies Adventure 28/30 mbar 4.5 kg

Best overall

Adventure Outdoor Supplies Adventure 28/30 mbar 4.5 kg
9.4/10about £13.95
View offer
IGT IGT 4.5 kg butane gauge

Rank 2

IGT IGT 4.5 kg butane gauge
8.6/10about £12.49
View offer
Cavagna Cavagna 0.5–2 bar POL

Alternative

Cavagna Cavagna 0.5–2 bar POL
8.0/10about £28.99
View offer
On this page
  1. 1.Pressures that UK appliances expect
  2. 2.Valves that go with each gas
  3. 3.Cold weather
  4. 4.Caravans

Pressures that UK appliances expect

Category I3+ is butane at about 28 mbar and propane at 37 mbar. Newer caravan supply is 30 mbar, marked I3B/P, so one pressure can feed appliances approved for both gases. That is not a licence to swap a 30 mbar part and a 37 mbar part. Calor's 4.5 kg butane page asks for a 29 mbar screw-on, inside the 28–30 mbar band. A propane barbecue is built around 37 mbar. Thirty millibar and 37 mbar are not close enough to swap. Read the plate, then buy the regulator that states that pressure. A dial does not change the set figure. The inlet check sits on the buying guide.

Valves that go with each gas

Butane in the UK uses two fittings. The 4.5 kg blue cylinder is a screw-on. Larger butane cylinders use a 21 mm clip-on, the pattern Calor associates with 7 kg and 15 kg bottles. Propane on a UK cylinder is POL. Patio gas is propane at 37 mbar on a 27 mm clip, even when the bottle looks small. Bullfinch lists the same three outdoor fittings: 20/21 mm butane, POL propane, and 27 mm patio. A butane gauge regulator will not feed a propane POL cylinder. The threads do not meet. In this capture the butane gauge rows are two 4.5 kg screw-ons and a 21 mm clip-on at 30 mbar. The other rows are a G7 pair plus adjustable bodies from Cavagna, Tezla, and ZYWUOY, marked in bar or PSI, not as a fixed 37 mbar part. No 27 mm patio regulator stayed in the set. Calor's FAQ also distinguishes UK POL from Irish jumbo butane and a 21.8 left-hand propane thread. The patio clip-on is the shared fitting.
Adventure Outdoor Supplies Adventure 28/30 mbar 4.5 kg

Testsieger

Adventure Outdoor Supplies Adventure 28/30 mbar 4.5 kg
9.4/10about £13.95
View offer

Cold weather

Butane vapour pressure collapses as the bottle gets cold. Calor says 4.5 kg butane works effectively above about −2 °C. Below that, a full butane cylinder can stop feeding a burner even though liquid is still in the bottle. Propane still vaporises in a British winter, on a 37 mbar regulator and the matching POL or 27 mm valve. A butane regulator with a gauge does not extend that range. A falling needle in the cold is not a reason to swap the regulator onto a propane cylinder.

Caravans

Until September 2003, caravan systems used split pressures. EN 1949 then moved new supply to 30 mbar for both gases, often on a bulkhead regulator, with the pressure marked in the locker. Use the regulator the locker plate names, commonly 30 mbar, not a 37 mbar barbecue clip and not a 29 mbar dumpy screw-on. A pre-change system can still be on the old split, so you read the plate rather than the year you remember. For a summer butane dumpy or a 21 mm butane bottle, stay on 28–30 mbar and that valve. For winter cooking on propane, use a 37 mbar regulator made for POL or the patio clip. Who should skip a high-pressure listing is on best gas regulator with gauge.

Common questions

Can one regulator run both butane and propane on a barbecue?
Not on an ordinary UK barbecue. Butane wants about 28–30 mbar on a screw-on or a 21 mm clip. Propane wants 37 mbar on POL or on a 27 mm patio clip. A gauge does not make those inlets compatible. A 30 mbar caravan system is a separate, plumbed case.
Why is patio gas 37 mbar if the bottle is small?
Because patio gas is propane. Bottle size does not set the pressure. The 27 mm clip and the 37 mbar regulator are the patio pair. This comparison did not keep a 27 mm gauge regulator.
Is propane better in winter?
For outdoor cooking in a British winter, yes, in comparison with butane. Calor puts effective butane use above about −2 °C. Propane continues to vaporise when butane has gone quiet, provided you use a 37 mbar propane regulator on POL or on a 27 mm patio valve. A butane gauge will not turn a cold butane cylinder into a winter propane supply.
What changed for caravans in 2004?
From September 2003, EN 1949 set new caravan gas supply at 30 mbar for both butane and propane, often from a bulkhead regulator, with the rating marked in the locker. Before that, systems used split pressures. The change does not rewrite barbecue fittings. A 37 mbar propane grill regulator and a 30 mbar locker regulator remain different parts. Read the plate in the locker.
Are Irish propane fittings the same as UK POL?
No. Calor's regulator FAQ treats UK propane as POL, and Irish propane as a 21.8 left-hand thread. Irish butane jumbo cylinders are a different butane fitting again. The patio clip-on is the one those notes share. If the cylinder is an Irish propane bottle, a UK POL regulator from this shelf is the wrong thread, even when both products are labelled propane.
Will a butane gauge regulator feed a propane POL cylinder?
No. The butane gauge rows here are screw-on 4.5 kg parts or a 21 mm clip-on. A UK propane cylinder is POL, at 37 mbar for a barbecue. The gauge cannot bridge that. Buy a propane regulator whose inlet is POL and whose outlet is 37 mbar, not a bar-range adjustable.

Related pages

How to fit a gas regulator

Gas regulator with pressure gauge

Best gas regulator with gauge UK for your cylinder

Gas regulator with pressure gauge: match the valve

Gas regulator gauge: how much gas is left in the bottle

Sources

Public UK sources used for this comparison. Listing prices, stars and review counts are the amazon.co.uk figures for these ASINs. Retrieved 22 October 2026.

  1. Liquid Gas UK: Consumer Guidance Sheet 39 (August 2020) (retrieved 22 October 2026)
  2. Calor: which hose and regulator for a gas barbecue (retrieved 22 October 2026)
  3. Calor: gas regulator FAQs (retrieved 22 October 2026)
  4. Calor: 4.5 kg butane cylinder (retrieved 22 October 2026)
  5. Camping and Caravanning Club: gas in caravans and motorhomes (retrieved 22 October 2026)
  6. Flogas: how to connect a propane cylinder (retrieved 22 October 2026)
  7. Gas Safety (Installation and Use) Regulations 1998 (retrieved 22 October 2026)
  8. GOK: does the regulator gauge show the filling level (retrieved 22 October 2026)