Leopard Gecko Heat Lamp Wattage by Tank Size

Leopard gecko heat lamp wattage depends on the tank, the room and the lamp height. There is no single number. Most setups start at 40 to 75 watts on a dimming thermostat.

Then you adjust until the warm spot reads about 28 to 32 C (82 to 90 F). The only wattage from a welfare body is 60 to 100 W for a guarded lamp. The tank size table below is common keeper practice, not a sourced rule.

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Why There Is No Single Wattage

Watts measure the power a bulb draws, and nearly all of it ends up as heat. The temperature your gecko feels depends on bulb distance, heat loss and room temperature. Two keepers using the same 60 W bulb can get a 10 degree difference in the warm spot.

That is why the target is a temperature, not a wattage. Wild Eublepharis macularius live in dry deserts and arid grasslands. By day they shelter under rocks or in burrows, according to Animal Diversity Web.

They absorb heat through their bellies, so a warm floor matters more than warm air.

Temperatures the Lamp Has to Reach

Veterinary sources agree on the shape of the gradient but not on exact numbers. The table lists what each source gives for an adult in a vivarium.

A practical target is 28 to 32 C on the floor at the warm spot. The far end should sit near 24 to 26 C. This page only covers how the lamp gets you there.

Leopard Gecko Heat Lamp Wattage by Tank Size

The RSPCA gives 60 to 100 W for a guarded ceramic or basking lamp on a 60 cm vivarium. No authority publishes a figure per tank size. The values below are common keeper practice.

They assume a basking bulb in a dome on top of the enclosure, in a room at about 20 to 22 C (68 to 72 F).

Tank dimensions are nominal and differ between makers, so measure your own. Start at the lower figure, then work upward only if the warm spot stays under target. A dimmer lets you own a stronger bulb and run it softly.

That is safer than a bulb that always runs at full output.

Size alone does not decide the pick, because a taller tank has a longer distance from lamp to floor. Wide, shallow tanks need less wattage than tall ones of the same volume. If you are still choosing an enclosure, the leopard gecko housing guide covers the options.

What Changes the Answer

Room temperature

A room at 16 C needs far more wattage than one at 24 C. The RSPCA says supplementary heat is needed when the room drops below 18 C (64 F). In a cool room, move up one step in the table.

Add a night source on its own thermostat if the enclosure drops under about 20 C.

Mesh top versus solid top

A mesh lid lets heat rise out and away, so a bulb above mesh feels weaker on the floor. A partly covered or solid top holds heat in, and the same bulb can overshoot. Merck, writing about reptiles generally, calls cutting ventilation to hold heat “ill advised”.

Adjust the wattage instead of sealing the lid.

Lamp height

Heat falls off quickly with distance. Lowering a bulb by a few inches raises the floor temperature far more than adding 10 W. Raising the bulb is the first fix when the warm spot is too hot.

Bulb type

A basking bulb gives light and heat, so it only runs by day. A ceramic heat emitter gives heat without light and can stay on at night. It has its own guide.

Merck notes that light bulbs cannot provide night heat in reptiles generally, because the animals need darkness.

Start Low and Dim with a Thermostat

Begin with the starting figure from the table and watch the probe for several hours before you change anything. Veterinary sources all call for a thermostat on every heat source. Merck says reptile heaters should be thermostat controlled and screened from the animals.

The RSPCA says to fit a thermostat with every heat source.

A thermostat with a probe lets the lamp be lighter and steadier. A dimming thermostat with a probe lowers the bulb output instead of switching it hard on and off. That suits a basking lamp.

Set the probe on the floor surface under the lamp, not in mid air.

For thermostat types compared, see the thermostat roundup.

The RSPCA also warns that thermostats are not always accurate, so confirm the number with a second thermometer. Never trust the dial alone. A failed unit can leave a lamp at full power and cook the floor beneath it.

A good first day looks like this:

1. Fit the bulb in a ceramic or heat rated fixture with a guard.
2. Set the dimmer so the probe reads 30 C (86 F).
3. Check the surface with a separate thermometer after two hours.
4. Adjust in small steps and wait before checking again.
5. Only add the gecko when readings stay steady for a full day.

A bulb that cannot reach 28 C at full power is too weak or too far away. Step up one row in the table or lower the fixture.

Measuring the Warm Spot

Measure at the surface where the gecko lies, because it takes heat through its belly. The RSPCA suggests checking daily with a digital or infrared thermometer. An infrared temperature gun gives an instant surface reading, and a digital probe gives a steady one.

Take readings at the warm spot, the middle and the cool end. Repeat them an hour after the lights come on. Note the highest and lowest values over a few days.

For more on tools, see the measurement gear guide.

Surface readings from an infrared gun can differ by a degree or two between substrates and finishes. Use the same spot and the same method each day so trends are clear.

Signs the Bulb Is Too Strong or Too Weak

The 35 C ceiling in the table is a keeper rule of thumb: it sits 3 degrees above the highest warm spot any veterinary source lists, which is the RVC figure of 32 C.

Behavior tells you when numbers are off, but read the thermometer first. A gecko that avoids the warm side all day or rests with its mouth open is probably too hot. One that sits under the lamp for hours and looks sluggish may be too cold.

Merck lists poor heat provision as a husbandry cause of nutritional secondary hyperparathyroidism in reptiles. It also says unfavorable temperature raises respiratory infection risk. That is reason enough to measure.

Persistent signs of illness call for a reptile veterinarian.

Placement and Safety

Merck links reptile burns to unscreened incandescent lights, and it says “hot rocks” frequently cause burns. The lamp must have a guard or sit outside the enclosure. The gecko must have no way to touch the bulb.

This species climbs, so keep decor away from the bulb.

Use a dome or fixture rated for the bulb wattage, and never exceed its limit. A basking bulb in a ceramic socket dome is the usual pairing. Keep cords, curtains and bedding well away from the hot parts of the fixture.

Check the fixture and plug monthly for scorching or loose sockets. Replace a bulb that flickers or darkens. For the equipment overview, see the leopard gecko heating and lighting guide.

For product picks, see best heat lamps for leopard geckos.

Frequently Asked Questions

What leopard gecko heat lamp wattage suits a 20 gallon tank?

A 40 W basking bulb is a common keeper starting point, run through a thermostat. Move to 50 or 60 W only if the floor under it stays below 28 C (82 F). A guard is needed in every case.

Is a 100 watt bulb too much for a leopard gecko?

It can be, in a small or low tank, because the floor can pass 35 C (95 F) quickly. In a 4 x 2 x 2 ft vivarium it is the top end, matching the RSPCA range of 60 to 100 W. On a dimmer it can run well below full power.

Should the heat lamp stay on all night?

Not usually. The RSPCA says heat is off at night unless the room is under 18 C (64 F), and the Royal Veterinary College says to stay above about 20 C. If the room is cooler, use a night source without light, on its own thermostat.

Can I use a heat lamp and a heat mat together?

Some vets use a mat as the main source and a bulb only if needed. Liverpool Veterinary Science lists a heat mat side at 30 to 35 C. If you combine them, put each on its own thermostat and check the warm side.

How far should the bulb sit above the floor?

There is no sourced distance, so set it by measurement. Place the bulb where the floor reads 28 to 32 C. Keep it high enough that the gecko cannot reach it.

How often should I replace the bulb?

Replace it when it fails, flickers or dims. Check the warm spot after each swap, since a new bulb may run hotter than the old one.