What color temperature replaces Cool White fluorescent tubes?

Choose 4000K (Neutral/Cool White) to match classic 4100K commercial Cool White tubes in offices and basements, or 5000K (Daylight) for garages and workshops.

Fluorescent Tube to LED Conversion Chart (T5, T8 & T12)

Q: Can I put an LED T8 tube into a T12 fluorescent fixture?

Physically yes: both 4-foot T8 and T12 tubes share G13 medium bi-pin sockets. Electrically, you must bypass the magnetic T12 ballast and wire a Type B ballast-bypass LED T8 tube directly to line voltage.

Q: Should I retrofit old 8-foot fluorescent tubes or replace the whole fixture?

Replacing an old 8-foot T12 fixture with a 4-foot or 8-foot integrated LED shop light is usually faster, safer, and comparable in price to buying 8-foot retrofit tubes and replacement sockets.

By LEDaBulb Editorial Team • Updated November 12, 2026

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Selection Methodology: Picks come from verified manufacturer data sheets, certification databases (DesignLights Consortium QPL for commercial fixtures, California Title 24 JA8, FTC Lighting Facts, and EPA ENERGY STAR for recessed downlights), and owner failure-rate analysis. We do not run hands-on lab tests.

Replacing 4-foot and 8-foot fluorescent tubes with LED tubes cuts fixture electricity draw by 45% to 65%, stops cold-weather flicker and ballast hum, and removes mercury glass from your ceiling.

Quick Answer: Replace both 32W T8 and 40W T12 4-foot medium bi-pin (G13) fluorescent tubes with a 12–18W LED T8 tube delivering 1,800–2,200 directional lumens. For modern electronic T8 ballasts in good shape, use Type A+B hybrid tubes for an instant swap. For older magnetic T12 ballasts or humming fixtures, wire Type B ballast-bypass tubes directly to 120–277V line voltage.

Fluorescent Tube to LED Wattage & Lumen Chart

Bare fluorescent tubes radiate light 360° around the glass, losing 25% to 35% of their rated lumens inside the upper troffer pan. LED tubes focus all light downward in a 120°–180° beam, so a 2,100-lumen LED tube matches or exceeds a 2,875-lumen 32W T8 on your desk or workbench.

Fluorescent Tube	LED Watts	Delivered Lumens	Savings / Yr*	Guide
15W / 17W T8 18–24 in · G13	7–9W	900–1,100 lm	$6.26	Calculate
28W T5 (HE) 46 in (4 ft) · G5	12–16W	~2,000 lm	$9.68	View 28W
32W T8 48 in (4 ft) · G13	12–18W	~2,100 lm	$11.39	View 32W
40W T12 48 in (4 ft) · G13	14–18W	~2,100 lm	$17.08	View 40W
54W T5HO 46 in (4 ft) · G5	24–27W	~3,500 lm	$19.07	View 54W
59W / 75W Slimline 8 ft · FA8 single-pin	36–44W	4,500–5,500 lm	$21.07	Calculate
110W T12HO 8 ft · R17d RDC	45–60W	6,500–8,000 lm	$41.28	Calculate

*Annual savings calculated on a commercial 12 hr/day, 365 day/year schedule at $0.13/kWh (including legacy ballast draw). On a residential 3 hr/day workshop schedule at $0.18/kWh, a 4-tube 40W T12 fixture saves ~$24/year.

Fluorescent tube to LED conversion chart comparing 2-foot, 4-foot, and 8-foot T5, T8, and T12 tubes with delivered lumens and Type A vs Type B ballast wiring — Printable fluorescent tube to LED chart (T5, T8, and T12 wattages, pin bases, and UL Type A/B wiring). Open full size Download PNG

Type A vs. Type B vs. Type A+B: Choose the Right LED Tube

Every linear LED tube falls into one of three UL wiring classifications. Mixing them up can blow an LED driver or leave the tube dark.

UL Type	How It Wires	Best For	Key Limitation
Type A (Plug & Play)	Clicks straight into existing sockets; runs off the existing electronic ballast.	Renters, offices with newer post-2005 electronic T8 ballasts, zero-wiring swaps.	Does not work on magnetic T12 ballasts. Ballast still consumes 2–4W and will eventually fail.
Type B (Ballast Bypass)	Cut out the old ballast and wire 120–277V line voltage directly to the lamp holders (tombstones).	Old humming T12 magnetic fixtures, garages, warehouses, permanent maintenance-free upgrades.	Requires basic electrical rewiring (shut off breaker first). Check single-ended vs. double-ended wiring diagram.
Type A+B (Hybrid / Dual Mode)	Runs plug-and-play on an electronic ballast today, and wires direct to line voltage later when the ballast dies.	Most homeowners and facility managers who want zero downtime now and future-proof Type B capability later.	Costs $1–$2 more per tube than single-mode Type B bulk packs.

Looking for vetted tube picks? See our Best LED Fluorescent Tube Replacement Guide (`Barrina`, `Sunco`, and `Philips InstantFit`).

Lumie's Tombstone Tip: Before wiring a single-ended Type B LED tube, inspect your fixture's plastic sockets (tombstones). Instant-start electronic T8 ballasts often use shunted tombstones (metal bridged internally across both contacts). Putting line and neutral onto one shunted tombstone creates a dead short. Either use double-ended Type B LED tubes (hot on one end of the fixture, neutral on the other, which works with shunted tombstones) or install the non-shunted tombstones included in single-ended kits.

T5 vs. T8 vs. T12 Diameter & Pin Compatibility

In North American lamp naming, the number after "T" measures tube diameter in eighths of an inch:

T12 (12/8 in = 1.5 in diameter): Legacy 40W magnetic-ballast tubes with G13 medium bi-pin ends (13mm pin spacing). Because T8 and T12 4-foot tubes share the exact same 48-inch length and G13 pin spacing, a 4-foot Type B LED T8 tube fits directly into a T12 fixture once you bypass the magnetic ballast.
T8 (8/8 in = 1.0 in diameter): Standard 32W commercial and garage tubes with G13 medium bi-pin ends. Accepts Type A (check manufacturer ballast list), Type B, or Type A+B LED T8 tubes.
T5 & T5HO (5/8 in = 0.625 in diameter): Slim 28W and 54W tubes measuring 45.8 inches long with G5 mini bi-pin ends (5mm pin spacing). T8 tubes will not fit a T5 fixture; buy dedicated 46-inch G5 LED T5 tubes or replace the fixture with a linkable LED shop light or 2×4 flat panel.

Electrical Safety Notice: Type B ballast-bypass retrofits place 120V–277V line voltage directly on lamp sockets. Always shut off power at the circuit breaker, verify zero voltage with a tester, apply the UL retrofit warning sticker inside the troffer pan, or hire a licensed electrician for commercial ceiling grids.

Frequently Asked Questions

Can I put an LED T8 tube into a T12 fluorescent fixture?

Physically yes: both 4-foot T8 and T12 tubes use the exact same G13 medium bi-pin sockets. Electrically, you must bypass the old T12 magnetic ballast and install a Type B (ballast-bypass) LED T8 tube, because standard Type A plug-and-play LEDs only work on newer electronic T8 ballasts.

Should I retrofit old 8-foot fluorescent tubes or replace the whole fixture?

In almost all garages and shops, replacing an old 8-foot T12 fixture with a 4-foot or 8-foot integrated LED shop light is faster, safer, and costs roughly the same as two 8-foot LED retrofit tubes plus new FA8 sockets.

What color temperature replaces Cool White (F40CW / F32T8/841) tubes?

Choose 4000K (Neutral/Cool White) to match classic `4100K` commercial Cool White tubes in offices, kitchens, and basements. Choose 5000K (Daylight) for garages, woodshops, and mechanic bays where crisp contrast helps spot small parts and fluid leaks.

References & Verification Standards: