Caravan Awning Size Calculator

The A-measurement is the total length of string or tape needed to run from the ground at one end of your caravan's awning rail, up and all the way around the rail channel, and back down to the ground at the other end. It's the single figure every full-awning size chart is built around — get this measurement right and the size lookup is mechanical.

Park on level ground with your normal touring load aboard (suspension compression under load changes the reading). Tie one end of a soft length of string or garden twine to a tent peg at ground level below one end of the awning rail, feed the string all the way through the rail channel, let it drop to the ground at the other end, then measure the total string length in centimetres. Enter that figure into the calculator above.

An unloaded, unhitched caravan sits slightly higher on its suspension than a loaded, hitched one — the difference is usually only a few centimetres, but that's enough to shift a borderline reading into a different size band. Measuring with your normal touring load gives the figure that matches how the caravan will actually sit on site.

Choose the larger (upper) size. The standard UK retailer convention rounds an exact boundary measurement up to the next band, since it also gives a small safety margin for uneven pitches and day-to-day variation in loading. The calculator applies this automatically and flags it as an "Exact Size Boundary" result.

Size up. A slightly larger full awning still fits and pitches correctly with a bit of slack in the fabric; a slightly undersized awning can be impossible to fit properly, or put constant strain on the rail channel and seams. The calculator's measurement-error scenario table shows how close your reading is to the next size up, so you can judge how much margin you have.

A full awning runs the entire length of one side of the caravan and is sized using the A-measurement system above. A porch awning is smaller, usually covering just the door area or one side section, and is chosen by rail height compatibility plus how much width of coverage you want — not by the A-measurement size-number system.

Porch awnings are matched on two things: whether your caravan's rail height (ground to the centre of the awning rail) falls in the compatible range for the awning — 235–250cm covers the vast majority of UK touring caravans — and how much width of coverage you want, typically a choice between 200cm (doorway only), 260cm (a single side entrance, the most popular size), 330cm (fuller coverage) or 390cm (large family/wraparound). Select "Porch Awning" above and enter your rail height to check compatibility and get a recommended width.

That's below the standard full-awning chart, which typically starts around Size 2 (675–700cm). This is common on smaller, compact or pop-top caravans. Rather than guess, check with a specialist compact-caravan or trailer-tent awning retailer, who will stock sizes designed for these smaller rail lengths.

That's above the largest standard size (Size 22, 1175–1200cm), which usually means a very large twin-axle caravan. Standard charts don't reliably cover measurements this large — contact a specialist retailer about a made-to-measure or bespoke-size awning rather than assuming the next number up on the standard chart will fit.

No — the chart used in this calculator is the generic UK industry chart that most full-awning brands follow, but several manufacturers (Isabella, Dorema, Bradcot and others) publish their own size tables that can differ by up to one band from the generic chart, especially at the smaller and larger ends of the range. Always check the specific product's own size chart before ordering, particularly if your A-measurement sits near a boundary.

You can as a rough starting point — some retailers offer model-specific lookup tools — but manufacturers change awning rail positions between model years and even between trim levels of the same model, so a name/age lookup can be wrong. A direct A-measurement of your actual caravan is the only figure every retailer's own guide recommends relying on to buy.

No. Motorhomes are measured differently — instead of a single ground-to-ground A-measurement, you need a separate loaded height measurement plus a length measurement that accounts for the position of doors, windows and roof vents, since these must sit either fully inside or fully outside the awning walls. Use a motorhome-specific size guide rather than this calculator's full-awning result.

That's implausible for any real caravan A-measurement or porch rail height, so the calculator shows "Check Your Measurement" rather than a fabricated size. It almost always means the wrong unit was selected (inches read as centimetres, or the reverse) or a decimal point was misplaced — re-measure and re-check the unit selector.

Most UK awning charts and product listings are labelled in centimetres, but some older charts, imported products or personal tape measures use inches. Showing both means you can cross-check the result against whichever unit a specific retailer's chart or your own tape measure uses, without doing the conversion yourself.

The A-measurement is a property of the caravan and its awning rail, not the tow car, so changing tow vehicles doesn't affect it. However, if you significantly change how the caravan is loaded for touring (for example adding a permanently fitted roof box or changing suspension components), it's worth rechecking the measurement, since ride height changes of more than a centimetre or two are enough to matter near a size boundary.