PAR20 vs PAR30 vs PAR38: A Buyer's Guide to Picking the Right Size

The difference between PAR20 and PAR30 is mostly size and reach. A PAR20 is 2.5 inches across for small fixtures and short throws, while a PAR30 is 3.75 inches across and pushes more light farther. PAR38, at 4.75 inches, is the largest and longest-reaching of the three. Shop Soraa PAR lamps.

Key Takeaways

• The number in a PAR lamp equals its face diameter in eighths of an inch, so PAR20 = 2.5 in, PAR30 = 3.75 in, and PAR38 = 4.75 in.
• A bigger diameter usually means room for more light output and a longer effective throw, which is why PAR38 suits high ceilings.
• PAR20 fits tight cans, small track heads, and accent spots where a compact lamp matters more than raw reach.
• PAR30 comes in short-neck and long-neck versions, and picking the wrong neck can leave the lamp recessed too deep or sticking out.
• Match the lamp size to your fixture opening and mounting depth first, then choose beam spread for the effect you want.
• Payless4Lighting stocks Soraa PAR20, PAR30, and PAR38 lamps in one place for easy comparison.

What PAR Means and How the Size Number Works

PAR stands for parabolic aluminized reflector. It describes a lamp with a built-in reflector shaped to gather light and aim it forward in a controlled cone. That shape is why PAR lamps work so well for spotlighting, accent lighting, and directional fixtures. The reflector does the aiming, so you get a defined beam instead of light scattering in every direction. The number that follows, such as 20, 30, or 38, is not about brightness or wattage. It is a size code, and once you know how to read it, the whole family makes sense. For shoppers comparing options, it also helps to see the sizes together, which is why many start with the range of Soraa PAR lamps.

Here is the rule that unlocks every PAR size: the number equals the face diameter measured in eighths of an inch. Divide the number by eight, and you get the diameter in inches. A PAR20 is 20 eighths, which works out to 2.5 inches. A PAR30 is 30 eighths, or 3.75 inches. A PAR38 is 38 eighths, or 4.75 inches. This is standard across the lighting trade, so it holds true no matter which brand you buy. Memorize that single conversion, and you will never be confused at the fixture aisle again.

One thing the size number does not tell you is beam angle. Two lamps of the same PAR size can throw a narrow spot or a wide flood depending on how the reflector and optics are built. Soraa, for example, uses point-source optics and tight beam control across its lines, and publishes its own beam figures for each model. So think of the PAR number as the body size and the beam angle as a separate spec you choose on top of it.

Physical Size and Fixture Fit

Size is the first thing to get right because a lamp that does not physically fit is a dead end. The face diameter decides whether the lamp seats cleanly in a recessed can, a track head, or a monopoint. A PAR20 slips into compact openings and small heads where space is tight. A PAR30 needs a wider housing but still fits many standard cans. A PAR38 is the broadest of the three and usually calls for a larger fixture opening and more room behind the ceiling.

Depth matters as much as width. Behind the ceiling line, a lamp needs clearance for its body and base, plus any trim or baffle in the fixture. This is where fixture depth and the lamp's overall length come into play. A short housing can crowd a long lamp, pushing the face past the trim so it stares out at the room. A deep housing can swallow a short lamp so the beam clips the trim edge. Always check both the opening diameter and the mounting depth of your fixture before you pick a PAR size.

Quick Comparison: PAR20 vs PAR30 vs PAR38

Feature	PAR20	PAR30	PAR38
Face diameter	2.5 in (20/8)	3.75 in (30/8)	4.75 in (38/8)
Typical use	Small accent, retail display, tight cans	General accent, track, medium ceilings	Longer throw, high ceilings, wide wash
Relative throw	Shortest of the three	Medium reach	Longest reach
Neck options	Single body style	Short-neck and long-neck	Single body style
Best fit for	Compact heads and monopoints	Standard recessed cans and track	Large cans and long-distance aiming

The table gives you a fast read, but the wattage-equivalent row is marked for a reason. Those numbers vary by model, brand, and lumen output, so check the exact figure on the spec sheet rather than assuming. Soraa publishes lumens, beam angles, and equivalency claims for each lamp, and those published figures are the ones to trust when you size a project. If you want to compare models across sizes and lines in one place, browse the full Soraa lamp range and read each product's stated specs side by side.

Light Output and Throw: Why Bigger Often Reaches Farther

A larger PAR lamp gives the reflector more surface to collect and shape light, so bigger sizes often carry more output and a longer effective throw. That is the practical reason PAR38 tends to win on tall ceilings while PAR20 suits close-in accent work. Throw is simply how far the beam travels before it spreads out and dims. A tighter beam concentrates light and reaches farther at a usable brightness. A wider beam covers more area up close but fades sooner over distance.

This is where beam angle meets lamp size in a way that actually affects your choice. On a 9-foot ceiling, a PAR20 with a narrow spot might land a crisp pool of light on a display below. On a 16-foot ceiling in a lobby, that same PAR20 may not have the reach, and a PAR38 with a controlled beam does the job better. You are balancing three things at once: the lamp size that fits, the output you need at the target, and the beam spread that gives the look. Get the size and throw in the right range first, then fine-tune the beam.

Color quality rides alongside output. Soraa lamps are known for high CRI and deep reds from their point-source design, which matters when you are lighting merchandise, food, artwork, or skin tones. The size you pick does not change a lamp's color rendering by itself, so choose the PAR body for fit and throw, then confirm the color specs, such as CRI and color temperature, from the model's published data.

PAR30 Short-Neck vs Long-Neck

PAR30 is the one size in this trio that comes in two body lengths, and mixing them up is a common mistake. A short-neck PAR30 has a stubby body designed for shallow fixtures and enclosed track heads where depth is limited. A long-neck PAR30 has an extended body that reaches down through deeper housings so the face sits closer to the trim. Same diameter, same beam options, different length behind the face.

Choosing the wrong neck creates two annoying outcomes. Put a long-neck lamp in a shallow head, and it may protrude past the fixture, looking awkward and glaring into the room. Put a short-neck lamp in a deep can, and it can sit too far back, so the trim shadows the edge of the beam. If you are replacing an existing PAR30, note which neck you have before ordering. If you are speccing new, match the neck to your fixture's depth, and when in doubt, check the fixture's cutsheet or ask before you buy.

Not sure which size lands cleanly in your fixtures? Browse the Soraa PAR20, PAR30, and PAR38 options at Payless4Lighting and compare the published specs side by side before you commit.

Which PAR Size to Pick for Common Jobs

For recessed cans, start with the can's opening and depth. Many 4-inch and small 5-inch cans take a PAR20 or a PAR30, while larger 6-inch cans commonly accept a PAR38. Check the trim you plan to use, since baffles and reflectors eat into the opening. When a can is shallow, a short-neck PAR30 often solves a depth problem that a long lamp would create.

For track heads, size is driven by the head itself. Compact heads and small monopoints are built around PAR20, giving you a tidy fixture for retail shelves and display niches. Standard track heads usually take PAR30, which is the workhorse size for accenting art, signage, and product tables at normal ceiling heights. Heavy-duty heads on tall tracks may accept PAR38 for extra reach.

For accent lighting at close range, PAR20 delivers a clean, contained pool without overpowering a small object. Stepping up to PAR30 gives you more punch when the object is larger, or the ceiling is a bit higher. Save PAR38 for longer throw, such as lighting a feature wall from across a room, washing a tall column, or reaching a target on a 14-to-20-foot ceiling where smaller lamps simply run out of reach. Whenever throw distance grows, the larger body and controlled beam of a PAR38 usually earns its place.

Frequently Asked Questions

What Is the Difference Between PAR20 and PAR30?

The main difference is diameter and reach. A PAR20 is 2.5 inches across, fits compact fixtures, and suits short-throw accent work. A PAR30 is 3.75 inches across, fits standard cans and track heads, and pushes more light over a longer distance. PAR30 also comes in short-neck and long-neck bodies, while PAR20 does not.

Is PAR38 Brighter Than PAR30?

Often, yes, but not automatically. PAR38 has a larger reflector, so many PAR38 models carry higher output and longer throw than comparable PAR30 lamps. Brightness still depends on the specific model's lumen rating, so compare the published lumens and beam angle for each lamp rather than assuming size alone decides it.

What Size PAR Lamp Fits a 4-Inch Recessed Can?

A 4-inch recessed can commonly takes a PAR20 or a smaller PAR30, depending on the housing and trim. Confirm the fixture's opening diameter and mounting depth before ordering. A PAR38 is usually too wide for a 4-inch can and is better matched to 6-inch cans and larger openings.

What Is the Difference Between Short-Neck and Long-Neck PAR30?

Both share the same 3.75-inch diameter, but the body length differs. A short-neck PAR30 fits shallow fixtures and enclosed track heads. A long-neck PAR30 has an extended body for deeper housings so the face sits nearer the trim. Match the neck to your fixture depth so the lamp neither protrudes nor sits buried.

Can I Swap a PAR30 for a PAR38?

Only if the fixture physically accepts the larger size. A PAR38 is nearly a full inch wider than a PAR30, so it needs a bigger opening and more depth. If the housing fits, a PAR38 can add reach and output; if it does not, stay with PAR30 and adjust the beam angle or wattage instead.

Need help sizing a PAR lamp or pricing a bulk order? Call (216) 533-9786 for a volume quote. Orders over $50 ship free anywhere in the USA.