Microscopy & measurement · SL/HL
Field-of-view density
Estimate number per area of a circular field of view.
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Number formats & units
Use decimal dots in datasets. Single values also accept decimal commas and scientific notation such as 1.2e-3 or 1.2 × 10⁻³.
Calculated locally. No account or input upload.
Result & working
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Interpretation & assumptions
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Formula & example
The relationship
What the variables mean
| Symbol | Meaning |
|---|---|
| Field-of-view diameter. | |
| count | Objects fully counted under a stated counting rule. |
Worked example
- Number counted
- 36
- Field-of-view diameter
- 0.50
- Diameter unit
- mm
- Density output
- per mm²
183.3465 mm⁻²
Follow the example steps
- Diameter = 500 µm
- Area = π(d/2)² = π(500/2)² = 196349.5 µm²
- density = count/area = 36/196349.5 = 0.0001833465 µm⁻²
- Convert: 0.0001833465 µm⁻² × 10⁶ = 183.3465 mm⁻²
Common mistakes
Use the radius, not the diameter, in circular area.
Incorrect approach
d = 2 mm, N = 20: A = π × 2² mm²
Correct approach
r = 1 mm: N/A = 20/π ≈ 6.366 mm⁻²
More checks before you submit
- A single field may be unrepresentative.
- Use a consistent edge-counting rule to avoid double counting.
Method notes
Repeat across multiple independent fields and calculate a mean if estimating tissue density.