OSHA does not set one single brightness number that every office has to follow. Instead, it requires that workplaces be adequately lit for safety.
In general, typical office tasks like reading, typing, and computer work are expected to have around 30 to 50 foot candles of light. That’s enough for most desk work without being overly intense.
OSHA is especially focused on safety. Exit routes must have enough illumination so people can safely leave in an emergency. There are minimum requirements for that, including at least one foot candle along exit paths.
Beyond specific numbers, the bigger point is visibility. If lighting is so poor that it increases the risk of trips, falls, or mistakes, that becomes a problem.
It’s also worth noting that OSHA standards are minimums. Many offices aim higher to improve comfort and productivity.
So the rule isn’t about making offices bright. It’s about making sure people can work and move around safely.