Aquariums, reptiles and equipment care · Guide + calculator

How Often To Replace UVB Bulb
without the guesswork.

Reptile UVB Bulb Decay Replacement Calculator — Track an exact lamp-label date while letting faults, UV meter readings and enclosure changes override the calendar. Includes a practical guide and embedded calculator. Inputs stay in your browser.

Reference toolReptile UVB Bulb Decay Replacement CalculatorTrack an exact lamp-label date while letting faults, UV meter readings and enclosure changes override the calendar. Inputs stay in your browser.
Reference calculation
Inputs

Enter your details.

Your inputs are processed locally and are not uploaded to CalcSpan.

Section 1

Core details

Start with the information that defines this calculation.

Tue, Oct 21, 2025
Fri, Aug 21, 2026
Use custom unless the lamp is the exact named product line.
The Zoo Med preset is documented for 10–12 hours per day; CalcSpan does not scale UV output linearly.
Section 2

Review and confirm

Check the remaining facts before calculating.

Plain-date semantics · start date is not counted unless the result explicitly says inclusive.

Your result
Next label replacement: Oct 21, 2026

The calendar follows the exact selected manufacturer label or a custom interval. A physical fault, low measured UV or enclosure-layout change overrides a date-only reminder.

Lamp scheduleZoo Med ReptiSun T8 5.0 · 12 months
First usedOct 21, 2025
Checked onAug 21, 2026
Daily operation11 hours
Lamp / fixture conditionOperating normally
Enclosure setupNo entered layout change
UV meter checkNot enteredVisible light is not a proxy for UVB output
Label replacement dateOct 21, 2026
Oct 21, 2026Replace or verify the UVB lamp per its label
Calendar options

Add to calendar

Choose a calendar service, then confirm the event. Downloading an .ics file does not add it until you open or import it.

Read before relying

Context matters.

  • Do not use one lamp model's lifespan, distance chart or UV percentage for a different product; choose custom when the exact preset does not match.
  • Mesh, reflectors, fixture type, distance and lamp orientation change the UV delivered at the animal's basking site.
  • Use a reptile veterinarian or current species care plan for the target UV Index, and follow electrical-safety and mercury-lamp disposal instructions.
Rule set 2.0.0

Sources & scope

Verified

This page shows the source trail, jurisdiction and review date alongside the result. Always confirm time-sensitive rules with the linked authority.

JurisdictionProduct-specific reptile lighting — selected manufacturer label or custom label interval
Review date2027-02-21
PrivacyNo input upload
Questions answered

What to know before using the result.

Can I choose a 12-month preset for any UVB lamp?

No. The presets apply only to the exact named product lines. Choose custom and copy the current product-label interval for any other lamp.

Why can a UV meter override the date?

The animal receives UV at the basking site, not at the bulb. A below-target reading can reflect lamp output, distance, mesh, fixture or orientation and needs investigation now.

Does visible brightness show that UVB is still adequate?

No. A lamp can still look bright while UV output has changed; use the product label and, when appropriate, a suitable meter and species care plan.