How It Works
This planner works in 4 steps.
List the pipettes
Select or type each pipette's minimum and maximum volume.
Enter the dilution
Type the stock, target, and final volume, or a multi-step scheme.
Assign pipettes
The planner matches every transfer to the pipette that places it highest in range.
Read the adjusted plan
The planner returns pipette per step and suggests a scale-up or predilution for out-of-range steps.
The Formula
The formula checks each transfer against each pipette's range and picks the pipette with the highest fraction of nominal.
V_min ≤ V_transfer ≤ V_maxf = V_transfer / V_maxPipette with the largest f within range- V_transfer:
- Volume to move
- V_min / V_max:
- Pipette range limits
- f:
- Position in range (1.0 = nominal)
A 15 µL transfer fits a P20 (75% of nominal) and a P200 (7.5% of nominal, below the 20 µL minimum). The planner assigns the P20.
Conversion Table
The conversion table lists typical ranges for 6 single-channel pipette sizes and the upper band where they perform best.
| Pipette | Minimum | Maximum | 10% of nominal | Preferred band |
|---|---|---|---|---|
| P2 | 0.2 µL | 2 µL | 0.2 µL | 0.7 – 2 µL |
| P10 | 1 µL | 10 µL | 1 µL | 3.5 – 10 µL |
| P20 | 2 µL | 20 µL | 2 µL | 7 – 20 µL |
| P200 | 20 µL | 200 µL | 20 µL | 70 – 200 µL |
| P1000 | 100 µL | 1,000 µL | 100 µL | 350 – 1,000 µL |
| P5000 | 500 µL | 5,000 µL | 500 µL | 1,750 – 5,000 µL |
Ranges are typical. Use the manufacturer's stated range for each model.
What Is the Pipette Range Dilution Planner?
The Pipette Range Dilution Planner is a tool that designs a dilution so every transfer falls within the specified range of the pipettes on hand. The user enters each pipette's minimum and maximum volume, and the planner assigns a pipette to every step.
Air-displacement pipettes are least accurate at the low end of their range. ISO 8655-2 sets tighter error limits at nominal volume than at 10% of nominal. The planner prefers transfers in the upper part of a pipette's range and splits or restructures any step that falls outside every available range.
Common Uses
There are 5 main uses of this planner.
Protocol design
Developers write protocols that fit common pipette sets.
Teaching labs
Instructors design dilutions for P20, P200, and P1000 only.
Field kits
Field teams plan with the 1 or 2 pipettes they carry.
Accuracy improvement
Analysts move transfers away from the bottom of a range.
SOP writing
QA teams name the pipette for every SOP step.