Optical density at 600 nm to million cells per milliliter
Type a value in OD600 to get it in 10⁶ cells/mL instantly.
That's 2× as dense as a culture in mid-log phase, while a culture in stationary phase is 2.5× denser. A 10 mL culture at that density holds about 8×10⁹ cells.
What it means
How dense is that culture?
Conversion factors are rules of thumb for a 1 cm path length. They differ between spectrophotometers, strains and growth phases, so calibrate your own.
The math
How to convert OD600 to 10⁶ cells/mL
Optical density is a proxy, scaled by the organism: cells/mL = OD600 × cells per mL at OD 1. The figures below use the organism selected above.
Example: 1 OD600 = 800 10⁶ cells/mL.
The table below is for E. coli (8 × 10⁸ per mL at OD 1).
Every unit
Your density in every unit
Tables
OD600 to 10⁶ cells/mL conversion table
| OD600 | 10⁶ cells/mL |
|---|---|
| 10,000 OD600 | 8,000,000 10⁶ cells/mL |
| 100,000 OD600 | 80,000,000 10⁶ cells/mL |
| 1,000,000 OD600 | 800,000,000 10⁶ cells/mL |
| 5,000,000 OD600 | 4×10⁹ 10⁶ cells/mL |
| 10,000,000 OD600 | 8×10⁹ 10⁶ cells/mL |
| 50,000,000 OD600 | 4×10¹⁰ 10⁶ cells/mL |
| 100,000,000 OD600 | 8×10¹⁰ 10⁶ cells/mL |
| 500,000,000 OD600 | 4×10¹¹ 10⁶ cells/mL |
| 1×10⁹ OD600 | 8×10¹¹ 10⁶ cells/mL |
10⁶ cells/mL to OD600 conversion table
| 10⁶ cells/mL | OD600 |
|---|---|
| 10,000 10⁶ cells/mL | 12.5 OD600 |
| 100,000 10⁶ cells/mL | 125 OD600 |
| 1,000,000 10⁶ cells/mL | 1,250 OD600 |
| 5,000,000 10⁶ cells/mL | 6,250 OD600 |
| 10,000,000 10⁶ cells/mL | 12,500 OD600 |
| 50,000,000 10⁶ cells/mL | 62,500 OD600 |
| 100,000,000 10⁶ cells/mL | 125,000 OD600 |
| 500,000,000 10⁶ cells/mL | 625,000 OD600 |
| 1×10⁹ 10⁶ cells/mL | 1,250,000 OD600 |
Quick answers
Quick answers
- How many 10⁶ cells/mL is 1 OD600?
- 1 OD600 is 800 10⁶ cells/mL.
- How many 10⁶ cells/mL is 10 OD600?
- 10 OD600 is 8,000 10⁶ cells/mL.
The units
About these units
Optical density at 600 nm (OD600)
What the spectrophotometer reads. A proxy for cell number, not a count.
Million cells per milliliter (10⁶ cells/mL)
How mammalian cell culture is usually counted.
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