Free Laser Calculators for Engravers & Cutters
Estimate engraving time before you hit start, calculate kerf compensation for precision cuts, and convert between speed, power, and DPI units. These interactive tools work with any LightBurn-compatible laser including xTool, OMTech, Sculpfun, Atomstack, and all GRBL-based machines.
Estimated engraving time
5m 34s
Line interval
0.1 mm
Total number of lines
1,001
line_interval = 25.4 / 254 = 0.1 mm
lines = 100 / 0.1 = 1001
time = 1001 x (100 / 300) x 1 = 333.7s
How to Use These Calculators
Engraving Time Estimator
Enter your engraving area dimensions, speed, and DPI to get an estimated engraving time. This calculation assumes raster (line-by-line) scanning, which is the standard mode for image and fill engraving in LightBurn. Actual times may be slightly longer due to acceleration, deceleration, and overscan at each line end.
Kerf Compensation Calculator
Measure the kerf width of your laser by cutting a straight line and measuring the gap with calipers. Enter that value along with your desired final dimensions. The calculator provides adjusted dimensions for both outer cuts (where the part is the material left behind) and inner cuts (where the part is the hole). Apply these offsets in LightBurn under Edit > Settings > Kerf Offset.
Power & Speed Converter
Quickly convert between mm/s, mm/min, in/s, and in/min speed units used by different laser controllers. Calculate actual wattage output from a power percentage, and convert between DPI and line interval values. This is especially useful when following settings guides that use different units than your software.
Frequently Asked Questions
- How do I calculate laser engraving time?
- Engraving time depends on your area size, speed, and DPI. First calculate the line interval (25.4 / DPI in mm), then the number of lines (height / line interval), and multiply by the time per line (width / speed). Our calculator above does this automatically — enter your dimensions, speed, and DPI to get an instant estimate.
- What is kerf width and why does it matter?
- Kerf is the width of material removed by the laser beam during cutting. A typical diode laser kerf is 0.1-0.3 mm, while CO2 lasers can be 0.1-0.4 mm. If you need precise dimensions (for example, interlocking parts or inlays), you must compensate for kerf by adjusting your cut path outward for external cuts and inward for internal cuts.
- How do I convert mm/s to mm/min?
- Multiply mm/s by 60 to get mm/min. For example, 100 mm/s = 6,000 mm/min. Some controllers and software (like LightBurn) use mm/s by default, while others use mm/min or in/min. Use our Power & Speed Converter tab above for instant conversions between all four common speed units.
- What power percentage should I use for engraving?
- For diode lasers (5-20W), typical engraving power is 30-80% depending on the material. Wood engraving usually works well at 40-60% power with 300-500 mm/s speed. Darker materials need less power. Always run test squares on scrap material first, adjusting power in 10% increments to find the best setting for your specific laser and material combination.
- How does DPI affect engraving time?
- Higher DPI means more lines per inch, which directly increases engraving time. Doubling the DPI roughly doubles the engraving time because twice as many lines need to be scanned. 254 DPI (0.1 mm line interval) is a good default for most engraving. Use 150 DPI for fast drafts and 318-508 DPI for photo engraving where fine detail matters.
Need help with laser settings?
Tell our AI assistant your machine model, material, and what you want to do. It will recommend exact power, speed, and DPI settings.
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