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Start My PlanYes — capable photometric software is free. DIALux EVO costs nothing, Visual from Acuity Brands has a free edition, and most fixture manufacturers will run a free layout for you. All of them compute real foot-candle numbers. The catch is the gap between a calculation and a permit-ready plan: that takes verified IES files, knowledge of the governing standards, and a format your plan reviewer accepts. Here is what the free tools do well, where they stop, and the point where hiring a specialist is the cheaper path.
If you are a contractor or owner weighing whether to self-serve, this is the honest version — including when DIY is genuinely fine.
Free and low-cost photometric tools
Three kinds of free options exist, and they are good at different things. None of them is the limiting factor in a permit submittal — the expertise around them is.
DIALux EVO (free)
Free from DIAL GmbH in Germany, funded by manufacturer catalog partnerships rather than user licenses. It models interior and exterior sites, places fixtures from 190+ manufacturer plugins, and calculates point-by-point illuminance grids. It is strongest at interior design and photorealistic 3D visualization. For how it stacks up against the paid US standard, see our DIALux EVO vs. AGi32 comparison.
Visual (free edition)
Visual, from Acuity Brands, offers a free lighting-design tool that handles interior and exterior calculations and quick area or roadway layouts. It is approachable and fast for a straightforward lot. Like any manufacturer-backed tool, its built-in catalog leans toward the sponsor's products, so cross-manufacturer optimization is limited.
Manufacturer layout services (free)
Most LED manufacturers and distributors will produce a free photometric layout when you request one. It is a sales tool — every fixture in it is a product they sell — which is reasonable when you are buying those fixtures anyway. The trade-offs, including where these layouts fall short for stricter jurisdictions, are covered in free vs. professional photometric plans.
For contrast, the paid standard for US exterior permit work is AGi32 (roughly $133/month, with a 14-day trial). It is not free, but its report format is what most US reviewers have read for decades — which is part of why permit-grade work tends to run through it.
What free tools can and can't do
A free tool calculates the same physics a paid one does. The difference shows up in everything that surrounds the calculation — the inputs, the compliance framing, and the format. Here is the honest split.
| What review depends on | Free DIY tool | Permit-grade plan |
|---|---|---|
| IES file accuracy | Only as good as the files you load — generic data skews results | Built from verified, fixture-specific IES files |
| Code compliance | You supply the standards knowledge | RP-8-25 and local code mapped in a compliance summary |
| Property-line trespass | Possible, if you set it up correctly | Documented at every boundary |
| Reviewer-ready format | Generic output; may need reformatting | Formatted to jurisdictional submittal expectations |
| Accountability | Yours | The designer's professional responsibility |
The DIY reality check
The software is the easy part. You can download DIALux EVO today and place fixtures by this afternoon. The expertise is the hard part, and it is the part that clears plan review.
Knowing which IES standard applies to your project, what uniformity ratio your reviewer expects, what light-loss factor to use for outdoor LEDs in your climate, how to document a Title 24 or dark-sky jurisdiction, and what grid spacing satisfies your specific plan reviewer — none of that comes with the download. A free tool computes the numbers. It does not know which numbers matter or how to present them. If you want to see what the output actually contains, understanding IES files is the place to start.
When to hand it to a specialist
DIY is genuinely fine for a quick internal sanity check, a single-fixture comparison, or a low-stakes layout in a jurisdiction with minimal submittal requirements. Hand it out when the project is headed for plan review, when the jurisdiction layers dark-sky or energy-code requirements, or when an idle crew makes a rejected submittal expensive.
That is the line our photometric plan service is built for: a permit-ready package — verified IES, a code-cited compliance summary, and a reviewer-ready format — modeled manufacturer-agnostic and delivered in 48 hours. If your site is already headed into plan check, request a quote and we'll confirm scope and a fixed fee, usually the same day.
Frequently asked questions
Is there free photometric software?
Yes. DIALux EVO is fully free, Visual from Acuity Brands offers a free edition, and most fixture manufacturers will run a free photometric layout when you ask. All of them compute real point-by-point foot-candle values. What they don't supply is the standards knowledge and reviewer-ready formatting that make a calculation into a permit submittal.
Can I make a permit-ready photometric plan with free software?
Technically yes, but permit-readiness is less about the software and more about what goes into it: verified IES files for the actual fixtures, knowledge of the governing code, property-line trespass documentation, and an output format your reviewer accepts. Free tools calculate accurately; clearing plan review takes the expertise around the calculation.
Is DIALux EVO good enough for a permit?
Its calculations are accurate. The open question for US exterior permits is the output format — most plan reviewers are used to AGi32-style reports, so a DIALux submittal may need reformatting to match jurisdictional expectations. For interior-only projects, DIALux output is widely accepted.
Do I need to buy software to get a photometric plan?
No. You can commission a photometric plan from a design service without owning any software. You provide the site plan and project details; the designer handles the modeling, calculations, and compliance documentation with their licensed tools and returns a permit-ready package.
Comparing tools because a permit is on the horizon? Skip the learning curve — request a quote and we'll produce the reviewer-ready plan for you.