A familiar wattage is not a brightness measurement. Modern LED lamps can produce the same light output while using very different amounts of power, so the useful comparison begins with lumens.
Start with the job the light must do
For a replacement lamp, look at the lumen value of the lamp you already like. For a new room plan, estimate the useful light needed at the task surface and then decide how several fixtures will share that work.
Read efficiency separately
Lumens per watt is an efficiency ratio. It can help compare energy use, but it does not describe beam shape, glare, color quality, dimming behavior or how much light reaches the work surface.
Use a practical checklist
- Match the fixture base and electrical rating.
- Choose a suitable lumen range.
- Check color temperature and color rendering.
- Confirm dimmer compatibility when applicable.
- Review beam angle and shielding.
Treat lumen calculations as planning estimates. Permanent wiring and uncertain electrical faults belong with a licensed professional.