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Electrical & Lighting / BUYING REFERENCE

LED bulb caps, shapes and sizes

Start with the cap marked on the existing bulb or specified by the light fitting. The cap code, physical dimensions and electrical rating all need to suit the fitting; a similar-looking bulb is not enough. Then choose the light output and colour temperature you want. Philips lists lumens, colour temperature, cap base and dimming status as separate properties. Compare those rather than using an old-style wattage equivalent as the only measure of the replacement.

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Search results. Match the specifications below to the selected listing.

Choose a replacement LED bulb by the cap and electrical requirements specified for the fitting, then compare physical size, lumen output, colour temperature and dimming. E27, E14, GU10 and G9 are separate cap codes, not interchangeable brightness labels. The named Philips UK examples below show why the cap is only the first step: even bulbs with similar output can have different shapes and control requirements.

Start with the cap code

Use the fitting's instructions and existing lamp marking to identify the required cap. These are examples of published specifications, not a compatibility list for unnamed fittings. Each row specifies 220–240 V; that is a property of the named product, not a rule covering every lamp with that cap.

Start with the cap code
CapPhilips UK example / EANPublished output and shapeManufacturer source
E278719514451018806 lm; A60 frosted bulbManufacturer reference ↗
E148718699762292806 lm; P45 clear lampManufacturer reference ↗
GU108718699776299390 lm; directional reflectorManufacturer reference ↗
G98720169301634220 lm; capsuleManufacturer reference ↗

Check supply and physical space separately

Other familiar-looking lamps have different electrical requirements. Philips GU5.3 reference 8718699773977 specifies a 12 V AC electronic supply, and G4 reference 8720169300491 also uses an AC electronic 12 V supply. Neither is established as a substitute for the GU10 or G9 examples merely by looking like a spotlight or capsule.

The E14 example is specified at 80 mm high and 45 mm wide. Its 806 lm output does not make it physically equivalent to the E27 row. Check the bulb's own dimensions, the fitting's allowed lamp type and operating conditions; the packaging measurements are a separate set of numbers.

Choose output, colour and control deliberately

Lumens describe light output, while the actual wattage and a traditional-wattage equivalence serve different purposes. Compare colour temperature in kelvin separately. A fixed-colour bulb and a WarmGlow dimmable model can share a cap without producing the same result as the control changes.

The detailed E27, GU10 and G9 references compare exact variants and their dimensions. E14 remains included here as another cap to identify. For any dimmed fitting, confirm the bulb is specified as dimmable and check compatibility with the exact control; cap type alone provides neither assurance.

Take the full specification and manufacturer code to the retailer comparison. Keep the selected quantity in view, because a product code can describe a multipack. The manufacturer examples support identification and comparison; they do not verify a particular Amazon offer or prescribe changes to the fitting.

Comparison sources

Manufacturer references checked 2026-10-03. These examples describe published specifications, rather than a hands-on review.

MATCH THE DETAILS TO YOUR JOB

What to check before buying

  1. Identify the exact cap and rated supply from the fitting's documentation.
  2. Compare bulb height, width and shape with the permitted space.
  3. Read lumens, actual watts and kelvin separately.
  4. Confirm dimming status and compatibility with the existing control.
  5. Verify the selected manufacturer code and number of lamps supplied.

Compare the related product types

E27 LED bulbs: output, dimensions and dimming →GU10 LED bulbs: beam, brightness and dimming checks →G9 LED bulbs: capsule size, output and dimming →

Reference & scope

Philips UK bulb specification reference

This page is a selection checklist for a product type. The manufacturer instructions and exact retailer listing determine suitability, included accessories and available variants.

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