GeckoCalc

Leopard Gecko Thermostat Setting Guide

💡 Quick Rule: Set the thermostat to 91–92°F so the warm-side floor surface reads 90–95°F. Keep the cool end at 75–80°F — and never run any heat mat without a thermostat.

🌡️ The Exact Temperatures

Leopard geckos need a thermal gradient — a warm end to digest food and a cool end to cool down. Here are the four numbers that matter, and the cheap tool that verifies each one:

MeasurementTargetCheck With
Warm-side floor surface90–95°F (32–35°C)Infrared thermometer (temp gun)
Cool-side ambient75–80°F (24–27°C)Digital thermometer on the cool wall
Night temperatureDown to 68°F (20°C) is safeNo heat needed in most rooms
Humid hide70–80% humidity insideDamp substrate, not a misted tank

🔧 What Type of Thermostat?

Two families dominate the hobby, and both keep your gecko safe — they just work differently:

  • On/off thermostats switch the mat fully on until the probe hits the target, then fully off. Simple and cheap; the surface temperature gently waves a few degrees around your setting.
  • Pulse proportional & dimming thermostats feed the mat just enough power to hold the target steady. More precise, quieter on the electronics, and the better pick if you might upgrade to a deep heat projector later.

🎯 Where the Probe Goes

The thermostat is only as accurate as its probe placement. Tape it flat on the glass floor, directly over the center of the mat, and let about half an inch of substrate cover it. That way the thermostat reads the exact surface your gecko lies on — nothing more, nothing less.

Where to place the thermostat probe — side view The heat mat sits under the tank on the outside of the glass. The thermostat probe goes on top of the glass floor, directly above the mat, under a thin layer of substrate and the warm hide. A red circle marks the probe position. Heat Mat — outside the glass Glass Thin substrate here Warm Hide Put the probe here! Thermostat
The probe rides on the glass above the mat — not in the air, not on the tank wall.

🦎 Building the Gradient

Your goal is a tank with two personalities: a warm end around 90–95°F where the mat, probe and warm hide live, and a cool end at 75–80°F with the water dish and humid hide. If both ends read the same, the mat is too big — check it with our heat mat size calculator.

Leopard gecko tank heat gradient — top view Half of the tank is the warm side at 90 to 95 degrees Fahrenheit with the heat mat and warm hide; the other half is the cool side at 75 to 80 degrees Fahrenheit with the cool hide and water dish. Warm Side 90–95°F Cool Side 75–80°F Heat Mat ≈ 1/3 of floor Warm Hide Cool Hide Water
A healthy gradient: one warm end, one cool end — with hides on both sides.

⚠️ Common Thermostat Mistakes

  • Running a mat without any thermostat. The single most dangerous mistake in the hobby — unregulated glass routinely exceeds 110°F.
  • Trusting the dial. Dial thermostats can be off by several degrees. Set with a thermometer, verify with a temp gun.
  • Probe on the outside of the glass under the mat. That measures the mat, not the surface your gecko touches. Always probe the floor surface above the mat.
  • One thermostat, two heat sources. A single channel can only regulate one mat. Two mats need two thermostats.
  • Hiding the probe under loose substrate. If the gecko digs the probe loose, readings crash. Tape it down flat and check it monthly.

❓ Frequently Asked Questions

What temperature should I set my leopard gecko thermostat to? ▾

Set it to 91–92°F (33°C). That keeps the floor surface directly above the mat at 90–95°F — the ideal basking zone — while the far end of the tank naturally settles into the 75–80°F cool range.

Do I need a thermostat for a low-wattage heat mat? ▾

Yes — every heat mat needs one, at any wattage. Even an 8 W mat climbs past 110°F without regulation. A thermostat is a $25–40 part that protects a pet that can live 20 years.

Where exactly does the probe go? ▾

Tape it flat against the glass floor, directly above the center of the mat, then cover it with about half an inch of substrate. Never leave the probe in open air or on the side glass — it will read the wrong temperature and the mat will overheat.

Can one thermostat control two heat mats? ▾

No. One thermostat channel per heat source. If you run two mats (or a mat plus a backup heater), each needs its own thermostat and its own probe, or neither is actually regulated.

Why does my mat feel barely warm when I touch the glass? ▾

That can be normal. A thermostat switches the mat off once the probe hits the target, so the surface often sits just under 92–95°F — warm, not hot, to a human hand. Trust a digital thermometer or infrared gun placed on the floor over the mat, not your palm.

🧭 Keep Setting Up

Calculator

Heat Mat Size Calculator →

Size the mat first, then set the thermostat that runs it.

 Calculator

Tank Size Calculator →

Check the minimum tank for your gecko's age.

 Guide

Lifespan & Care Guide →

Correct heat is step one — here's the next twenty years.