Calculator Form
Use direct measurements, endpoint coordinates, or full time-series tracking data. The form uses three columns on large screens, two on medium screens, and one on mobile.
Formula Used
Basic speed: Speed = Distance ÷ Time
Net displacement: Displacement = √[(x₂ − x₁)² + (y₂ − y₁)²]
Tracked path length: Path Length = Sum of all segment distances across the trajectory.
Average path speed: Average Path Speed = Total Path Length ÷ Total Time
Net speed: Net Speed = Net Displacement ÷ Total Time
Directionality ratio: Directionality = Net Displacement ÷ Total Path Length
Replicate CV: CV = (Standard Deviation ÷ Mean) × 100
Directionality values near 1 indicate straighter movement. Lower values suggest meandering or exploratory migration.
How to Use This Calculator
- Select the calculation mode that matches your experiment.
- Choose the input distance and time units.
- Enter image scale if your measurements are in pixels.
- Provide direct values, endpoint coordinates, or a full tracking sequence.
- Optionally add replicate speeds for summary statistics.
- Press the calculate button to show results above the form.
- Review the chart, summary table, and interval metrics.
- Download the results as CSV or PDF for reporting.
Example Data Table
Example tracked cell positions for a single experiment using minutes and micrometers.
| Time (min) | X (µm) | Y (µm) | Comment |
|---|---|---|---|
| 0 | 0 | 0 | Initial position |
| 10 | 18 | 6 | Early directional shift |
| 20 | 39 | 15 | Persistent forward movement |
| 30 | 63 | 28 | Highest interval displacement |
| 40 | 79 | 39 | Continued migration |
Frequently Asked Questions
1. What does this calculator measure?
It measures cell migration speed using direct distances, endpoint displacement, or multi-point trajectories. It also reports net displacement, directionality, interval speeds, and replicate summary statistics when provided.
2. When should I use tracked path mode?
Use tracked path mode when you have time-lapse coordinates from microscopy software. It gives a more complete picture because it captures turning behavior, total path length, and interval-by-interval speed changes.
3. What is directionality ratio?
Directionality compares straight-line displacement to total traveled path. A value close to 1 means straighter motion, while lower values indicate a more wandering or exploratory trajectory.
4. Can I use pixel coordinates?
Yes. Select pixels as the distance unit and enter the microscope calibration as micrometers per pixel. The calculator converts pixel movement into physical distance before computing speed.
5. Why are path speed and net speed different?
Path speed uses the full traveled distance. Net speed uses only the straight displacement from first to last point. They differ when cells change direction during movement.
6. What should I enter for replicate speeds?
Enter one numeric speed per line using the currently selected output speed unit. The calculator summarizes mean, median, standard deviation, range, and coefficient of variation.
7. Is this useful for wound healing assays?
Yes. It is useful for wound healing and single-cell tracking studies, especially when you convert image coordinates into physical units and compare replicate migration speeds across conditions.
8. Does this replace full image analysis software?
No. It is a reporting and calculation tool. Use dedicated image analysis software for segmentation and tracking, then bring the measured distances or coordinates here for fast interpretation.