Finally passed IES after two attempts — what actually worked for me

by Sofia R. 585 views3 replies
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Sofia R.OP
May 27, 2026

So I passed the IES exam last month on my second try and wanted to share what made the difference, because honestly the first time I had no idea what I was walking into. I'm a lighting designer with about four years of experience and figured my on-the-job knowledge would carry me. It did not. I failed by 11 points and was pretty devastated.

The second time around I gave myself 10 weeks and actually followed a real study plan. The biggest game-changer was working through an IES practice test every weekend and reviewing every wrong answer — not just checking the answer, but understanding the underlying principle. I also found a solid study guide that organized the NCQLP content outline by domain, which helped me stop randomly reviewing and start filling actual gaps. Photometry and the energy code sections were brutal for me personally.

Anyone else finding the calculations section harder than expected? I keep seeing people say it's mostly conceptual but there were definitely more math-heavy questions on my exam than I anticipated. Happy to share more tips if anyone's prepping right now.

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Sofia R.
May 28, 2026
Congrats on passing! I'm currently about five weeks out from my exam date and the calculations are killing me too. Specifically the illuminance/luminance conversions and inverse square law stuff. I've been doing practice questions daily but I feel like I need more timed exam simulations. Did you find the real exam's time pressure was worse than the practice tests, or about the same?
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Jordan L.
May 28, 2026
Two attempts is actually really common — I don't think people talk about that enough. The pass rate for first-timers isn't great. My exam tip that nobody told me: read the IESNA Lighting Handbook chapter summaries before you do anything else. I wasted three weeks on random YouTube videos before I got organized. A proper study guide that maps to the actual exam domains saved me at least a month of wasted effort.
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David K.
May 28, 2026
The math section trips everyone up. Seriously just drill the foot-candle to lux conversions until they're automatic — same with the coefficient of utilization problems. Once those feel mechanical you free up mental energy for the harder conceptual questions. Good luck to everyone sitting this year!

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