Free Online IES Viewer (No Signup)
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What Is an IES File?
An IES file (extension .ies) is the standardized text-based photometric data format published by the Illuminating Engineering Society of North America under specification LM-63. It describes how a luminaire distributes light in three dimensions — luminous intensity (candela) measured at a grid of vertical and horizontal angles — together with metadata such as total lumens, wattage, beam angle, lamp type, and physical dimensions.
Lighting designers, architects, and engineers use IES files to model real luminaires inside calculation tools like AGi32, DIALux, Visual, Relux, ElumTools, and our own CircadianLab. Almost every commercial luminaire manufacturer publishes IES files for download on their product pages.
How to View an IES File Online
- 1
Open your file
Click "Open an IES File" above, or drag and drop your .ies file onto the viewer area.
- 2
Inspect the photometric data
The viewer parses the file in your browser and renders the 2D polar plot, 3D goniometer surface, beam-analysis charts, iso-footcandle plot, and full specification table.
- 3
Download or use in CircadianLab
Re-download the file unchanged, or open it inside CircadianLab to run room-level EML, illuminance, and UGR calculations.
Features
2D Polar Plot
C0–C180 and C90–C270 plane intensity curves on a single chart with candela ring labels.
3D Goniometer Surface
Interactive 3D surface — drag to orbit, scroll to zoom — color-graded by intensity.
Cone of Light
Beam diameter and center footcandles/lux at standard mounting heights (8/10/12/15 ft).
Zonal Lumen Distribution
Five-bin breakdown showing direct vs indirect output and downward distribution shape.
Iso-footcandle Plot
Floor-plane illuminance heatmap with selectable mount height and fc/lux units.
Full Specification Table
Manufacturer, lamp, test lab, lumens, peak candela, watts, efficacy, dimensions — every IES keyword.
No Upload Required
Files are parsed entirely in your browser. Nothing is sent to our servers.
Standards-Compliant
Reads IESNA LM-63 from 1986 through 2019. Supports Photometric Types A, B, and C with all symmetries.
Open in CircadianLab
Take the same file straight into our free EML, illuminance, and UGR calculator.
Supported File Formats
Most commercial luminaire manufacturers publish IES files in LM-63-2002 format. The viewer auto-detects the version.
Your Files Stay on Your Computer
IES files are parsed in your browser using JavaScript. Nothing is uploaded, stored, or shared. We may use standard site analytics, but the IES content itself never leaves your device.
Frequently Asked Questions
▶What is an IES file?
An IES file (.ies) is a standardized text-based photometric data file from the Illuminating Engineering Society. It describes how a luminaire distributes light in 3D using candela values measured at a grid of angles, plus metadata like lumens, wattage, beam angle, and lamp type.
▶Is my IES file uploaded to your server?
No. The file is parsed entirely in your browser. Nothing is sent to our servers and we never store or share your file contents.
▶What does the polar plot show?
The 2D polar plot shows luminous intensity in candela for the C0-180 (vertical) and C90-270 (horizontal) planes. Angles are measured from nadir (0° = straight down). The 3D goniometer surface shows the full distribution.
▶How is the beam angle calculated?
The beam angle is the full cone width where intensity drops to 50% of peak — the standard industry definition for downlights and accent fixtures.
▶What does the iso-footcandle plot represent?
The iso-footcandle plot shows floor-plane illuminance from a fixture mounted at a given height and aimed straight down. Contour lines mark equal illuminance levels in fc or lux. Computed via E = I(θ) · cos³(θ) / h².
▶Can I open this file in a lighting design tool?
Yes. IES is the universal photometric format. Use it in CircadianLab, AGi32, DIALux, Visual, Relux, ElumTools, or any major lighting calculation package.
IES is a registered trademark of the Illuminating Engineering Society. Innerscene is not affiliated with the IES.