UK Double is 3.8 mm wider; the exact-converted US Full is 5 mm longer.
The calculated surface-area difference is 0.0%, measured relative to US Full.
US Full is also called Double, creating a naming collision with the UK Double. Their nominal outlines are close but not sourced as one standard.
The figures above are calculated from the identified dimensional records, not from rounded display conversions.
UK Double is 3.8 mm wider; the exact-converted US Full is 5 mm longer.
Rigid frames, enclosed bases, fitted sheets and protectors should be selected from finished product measurements and depth—not from the closest name.
Review UK Double dimensions and tolerance · Review US Full dimensions and tolerance · Compare another country-qualified pair · Measure before buying
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