Best Lux Meters for Indoor Lighting

For repeatable readings on a desk or workbench, our pick is the Extech LT300: its separate sensor can sit on the work surface while you read the display elsewhere. Choose the REED R1630 for compact room checks and app logging, or the HIOKI FT3424 for its low-light range and more fully documented sensor response. These recommendations come from manufacturer documents, without physical testing.

Quick picks

Compare specifications and all conditions

Extech LT300

Our pick for

Repeatable desk and bench checks

Sensor arrangement

Separate sensor; cable extends to 61 cm

Lux coverage; finest display step

Up to 400,000 lux; 0.01 lux on the 40 lux range

All specifications

Recording

Hold, MIN/MAX and relative mode

REED R1630

Our pick for

Compact checks and app logging

Sensor arrangement

One-piece handheld

Lux coverage; finest display step

0–100,000 lux; finest listed step 0.1 lux

All specifications

Recording

Timed logging through Smart Series App

HIOKI FT3424

Our pick for

Low-light checks and sensor documentation

Sensor arrangement

Docked sensor; optional L9820 cable separates it

Lux coverage; finest display step

0–200,000 lux; 0.01 lux on the 20 lux range

All specifications

Recording

Memory for 99 values; USB transfer

Full comparison table ↔

Swipe to compare. Row labels stay visible.

Meter	Our pick for	Sensor arrangement	Lux coverage; finest display step	Recording
Extech LT300	Repeatable desk and bench checks	Separate sensor; cable extends to 61 cm	Up to 400,000 lux; 0.01 lux on the 40 lux range	Hold, MIN/MAX and relative mode
REED R1630	Compact checks and app logging	One-piece handheld	0–100,000 lux; finest listed step 0.1 lux	Timed logging through Smart Series App
HIOKI FT3424	Low-light checks and sensor documentation	Docked sensor; optional L9820 cable separates it	0–200,000 lux; 0.01 lux on the 20 lux range	Memory for 99 values; USB transfer

Meter	Our pick for	Sensor arrangement	Lux coverage; finest display step	Recording
Extech LT300	Repeatable desk and bench checks	Separate sensor; cable extends to 61 cm	Up to 400,000 lux; 0.01 lux on the 40 lux range	Hold, MIN/MAX and relative mode
REED R1630	Compact checks and app logging	One-piece handheld	0–100,000 lux; finest listed step 0.1 lux	Timed logging through Smart Series App
HIOKI FT3424	Low-light checks and sensor documentation	Docked sensor; optional L9820 cable separates it	0–200,000 lux; 0.01 lux on the 20 lux range	Memory for 99 values; USB transfer

These are display steps, not accuracy guarantees. The LT300 and R1630 also display footcandles; the FT3424's documented display unit is lux.

Best for desk and workbench checks: Extech LT300

Choose the LT300 when sensor placement matters more than fitting everything in one hand. Its datasheet specifies a coiled sensor cable extending from 30.5 to 61 cm; the manual says the sensor is permanently attached. You can place the sensor on a desk or tabletop under overhead lighting and keep the display in view.

Manual range selection lets you choose the range with the finest usable resolution. Relative mode displays the difference from a stored reference, while MIN/MAX retains extremes. Record ordinary readings in the worksheet below; MIN/MAX retention is not a timestamped lighting log.

Order the right package: the standard LT300 includes a battery, sensor cover, protective holster and soft case. The datasheet identifies LT300-NIST as the version with calibration traceable to NIST; do not assume that paperwork accompanies the standard model.

Trade-offs: the cable gives limited reach, and the full accuracy formula includes a range-dependent term. The official datasheet and manual also disagree on dimensions and weight; confirm those details if carrying size matters. We do not select one document's figures as definitive.

See the LT300 and package options at Extech

Best compact option with app logging: REED R1630

The R1630 suits a room-to-room survey when you want a compact instrument with its own display. REED's product page lists a magnetic back, tripod mount and data hold. Its display works without a mobile device; timestamped logging requires the Smart Series App for iOS or Android.

With the app, REED specifies selectable sampling intervals from 1 to 120 seconds and PDF or Excel export. That makes it our choice here for recording changes over time, provided you are willing to keep a mobile device in the workflow. Ask REED for quantified spectral and cosine-response information before choosing it for LED acceptance measurements.

Variants: the standalone R1630 includes batteries. The datasheet lists R1630-KIT with an R1500 tripod and CA-05A medium soft carrying case, and R1630-NIST as the calibration option. Check the certificate's scope before ordering.

Replacing an R1930? REED now marks the R1930 discontinued and identifies the R1630 as its direct replacement. This is not simply a renamed meter: the older model's manual lists 1 lux as its finest lux step, versus 0.1 lux for the R1630.

See the R1630 at REED

Best for low-light work and sensor documentation: HIOKI FT3424

Choose the FT3424 when you need to understand the sensor's limits as well as record a reading. HIOKI's product page explicitly lists LED compatibility, DIN Class B and JIS general AA classification. Its lowest range is 20 lux with 0.01 lux steps; the meter stores up to 99 readings for later USB transfer.

Timer hold lets you move away before capturing a reading, reducing the operator's shadows and reflections. For a separate sensor and display, order the optional L9820 connection cable. A remote-sensor setup is not included merely because the head can undock.

FT3424 or FT3425? HIOKI's family brochure says the measurement specifications are shared and identifies Bluetooth as the FT3425's addition. Choose the FT3425 if wireless transfer is the reason to upgrade; choose the FT3424 for the documented low-light ranges and USB workflow.

Trade-offs: HIOKI's manual distinguishes linearity from its full-scale verification tolerance. Its classification and fine display do not justify calling it universally accurate to the smallest displayed digit. We use the English/Japanese revision 10 linked on HIOKI's product page.

See the FT3424 and accessories at HIOKI

How we choose

We compared official product pages, manuals and datasheets, read November 2, 2026. We prioritized usable sensor placement, range-specific accuracy, spectral and angular documentation, recording and calibration options. The R1930 was removed from the proposed shortlist after checking its status. Recommendations describe suitability on paper; no independent readings or popularity ranking are claimed. Our selection method and measurement policy explain the approach.

Buying guide: read the surface, range and sensor specification

Lux, footcandles and a useful target

Lux describes light arriving at a surface. A lumen per square metre is a lux; a lumen per square foot is a footcandle. To convert, 1 footcandle ≈ 10.76 lux; multiply footcandles by that factor, or divide lux by it. The underlying conversion is in NIST's units table.

Choose a target for the actual task. CCOHS's lighting guidance gives these examples:

Treat these as guidance, not a universal compliance threshold. CCOHS separately considers glare, contrast and shadows: a satisfactory lux number does not settle those questions.

Compact sensor or remote sensor?

A compact meter is our preference for a quick handheld survey. For a repeated desk measurement, we prefer placing the sensor and then reading without moving it. The LT300 supports tabletop placement; the FT3424 offers timer hold and optional sensor separation.

• Yes: Choose the R1630 when a compact meter and app records suit the job
• Yes: Choose the LT300 when a separate sensor and readable display position matter
• Partly: Choose the FT3424 for separation only after adding the optional L9820 cable

Resolution is not accuracy

The LT300 manual specifies ±(5% of reading + 0.5% of full scale). Calculated example: a 500 lux reading on its 4000 lux range has a stated tolerance of ±45 lux: 25 lux from the reading term plus 20 lux from the range term. This illustrates the published formula, not an observed error; use the lowest range that accommodates the reading.

For HIOKI, the manual increases the linearity allowance above 3000 lux and adds a digit term below one-third of a range. Do not rank these meters by the percentage headline alone: the quantities and conditions differ.

LEDs: ask what the sensor response means

Spectral response describes how a meter weights different wavelengths; cosine response concerns light arriving at different angles. NIST defines f1′ as mismatch from the CIE visual-response function. HIOKI quantifies this and angular response; Extech documents correction, while REED's cited specifications leave those quantities unstated.

An LED label cannot supply the uncertainty for every lamp. NIST's calibration guidance explains that spectral mismatch errors arise when the measured source differs from the calibration source. For an acceptance report, ask the calibration provider about your source spectrum and measurement range.

Lux also cannot supply an unknown grow light's PPFD through one universal multiplier: Apogee's conversion tables vary by light source. Assess glare separately and request the lamp's color-quality data when that is part of the decision.

Make a repeatable indoor-lighting record

Use this suggested worksheet for comparisons. It records conditions as well as readings; the blank rows are not sample measurements.

1. 1

   Define the task surface

   Mark the sensor position, height and orientation where the work happens.

2. 2

   Record the lighting state

   Note lamps, dimmer setting, blinds, daylight and time before each comparison.

3. 3

   Prepare the meter

   Follow its manual, including cap removal and any specified zero adjustment; choose the appropriate range.

4. 4

   Capture and repeat

   Let the reading stabilize, record it, then repeat at the same marked locations after the change.

The LT300 manual permits tabletop placement for overhead lighting. HIOKI instructs users to zero with the cap attached, then uncover the sensor and read after stabilization. Avoid adding your own shadow during an installation comparison; for a task-use assessment, CCOHS says the worker should sit in the normal working position. Record which setup you used.

Session: date/time ___; meter and calibration reference ___; lamps/dimmer ___; daylight/blinds ___; task ___; operator position ___.

Keep the same locations and lighting conditions when comparing a change; document any exceptions. For the R1630, also record the app sampling interval. For HIOKI, keep a location list alongside the stored readings.

Calibration: REED's manual says factory calibration is part of manufacture and a certificate is a separate service. Extech offers LT300-NIST, while HIOKI recommends calibration every 2 years. Ask for the certificate's measurement points, uncertainty and relevant source conditions; zero adjustment is not a substitute for that record.

If the next question is electrical use rather than illumination, continue to our plug-in watt meter guide. For another room-condition survey, see our sound level meter guide.

Verdict

Get the Extech LT300 for a separate tabletop sensor and deliberate range selection, the REED R1630 for compact checks with optional app logging, or the HIOKI FT3424 for low-light ranges and quantified sensor documentation. Choose the form factor first, then check the accuracy conditions and certificate requirements. Keep the measurement setup with the result.