How to Choose a Pipette: Types, Calibration & Buying Guide

Choosing the right pipette comes down to four things: the volume you work at, the liquid you handle, how often you pipette, and the accuracy your results demand. Get those right and the instrument disappears into the background; get them wrong and the pipette quietly biases every measurement it touches. This guide walks through the pipette types, the air-versus-positive-displacement decision, calibration, and a clear four-question framework for choosing the right one.

It is written for Australian and New Zealand labs, with local buying and NATA-accredited calibration guidance throughout. Accuracy depends as much on the type and technique as on the model you buy. For solution preparation and volumetric accuracy more broadly, see our complete guide to laboratory glassware in Australia.

How to Choose the Right Pipette

Work through four questions in order:

These questions reference a few terms — air versus positive displacement, accuracy classes, and channel counts — that the rest of this guide unpacks in detail below. As a quick reference, here is how common scenarios map to a pipette type:

Which Pipette for Which Job

If you are unsure, our technical team will match the pipette to your application rather than sell you the most expensive option.

What Is a Pipette?

A pipette is a laboratory instrument used to measure and transfer a precise volume of liquid from one container to another. Volumes range from fractions of a microlitre in molecular biology to tens of millilitres in classical analytical chemistry. Unlike a beaker or measuring cylinder, which only estimate volume, a pipette is built to deliver a specified amount with a defined and certifiable accuracy.

Pipettes fall into two broad worlds. Mechanical (piston-operated) pipettes use a moving piston to draw and dispense liquid and are the workhorses of modern life science labs. Glass transfer pipettes rely on capillary action and gravity and remain the reference standard for high-accuracy volumetric work. Both have their place, and most labs run a mix of the two.

Types of Pipettes

There is no single "best" pipette. The right choice depends on the liquid, the volume, and how the result will be used.

Piston-Operated (Mechanical) Pipettes

These are the adjustable, hand-held pipettes used with disposable tips. They divide further by mechanism, operation, and channel count.

The Gilson PIPETMAN range is the most widely recognised example: PIPETMAN Classic and PIPETMAN L for manual air-displacement work, PIPETMAN M for electronic pipetting, and Microman E for positive displacement. For a model-by-model breakdown, see our Gilson PIPETMAN range selection guide.

Glass Transfer Pipettes

These have no moving parts and are filled using a pipette bulb or a macro pipette controller.

• Volumetric (one-mark) pipettes: deliver a single, highly accurate fixed volume. Manufactured to ISO 648 and available in Class A and Class B, where Class A carries the tightest tolerance and is the standard for analytical work.
• Graduated (Mohr and serological) pipettes: marked along their length to deliver a range of volumes, manufactured to ISO 835. Less accurate than volumetric but more flexible. Sterile serological pipettes are common in cell culture and media work.
• Capillary micropipettes: disposable glass or plastic capillaries for very small fixed volumes, such as Hirschmann minicaps and Microcaps glass micropipettes, used in haematology, microsampling, and reference measurement.
• Pasteur pipettes: simple glass or plastic droppers for non-quantitative transfer, where volume does not need to be measured at all.

Air Displacement vs Positive Displacement

This is the distinction most labs get wrong, and it directly affects accuracy.

The practical rule: use air displacement for everyday aqueous work, and switch to positive displacement whenever the liquid is thick, evaporates readily, or is much denser than water. Glycerol, DMSO, organic solvents, and concentrated protein solutions are common cases where an air-displacement pipette will silently under-deliver. If you regularly handle high-viscosity samples, our guide on viscosity and how it is measured explains why the air cushion behaves the way it does.

Manual vs Electronic Pipettes

Manual pipettes are reliable, affordable, and perfectly suited to routine work. Electronic pipettes add motorised aspiration and dispensing, which improves repeatability across long runs, reduces operator fatigue and the risk of repetitive strain injury, and enables modes like repeat-dispense, mixing, and serial dilution. For a high-throughput lab running the same protocol hundreds of times a day, an electronic model such as the PIPETMAN M electronic pipette often pays for itself in consistency and ergonomics alone.

Pipette Calibration: Why It Matters

Every piston-operated pipette drifts over time. Seals wear, springs fatigue, and a pipette dropped even once can fall out of specification without any visible damage. A pipette that is 5 percent out is still comfortable to use and looks perfectly normal, yet it will bias every result it touches.

Calibration is the process of verifying and adjusting a pipette against a traceable reference. The internationally accepted method is gravimetric: the pipette dispenses purified water onto a precision balance, and the measured mass is converted to volume using the density of water at the test temperature. ISO 8655 is the standard that governs piston-operated volumetric apparatus and defines the test procedure and the permissible error limits.

John Morris Group provides NATA-accredited pipette calibration (Accreditation No. 4283) through factory-trained engineers across Sydney, Brisbane, Melbourne, Perth, and Auckland. We also supply in-house verification systems such as the Artel PCS pipette calibration system and the Artel MVS multichannel verification system for labs that need to check liquid handling between scheduled calibrations. For the full picture on accreditation and service intervals, see our NATA pipette calibration guide.

As a general rule, calibrate every 3 to 6 months, and more often for high-use pipettes or critical applications. Your quality system, not convenience, should set the interval.

Pipetting Technique: Forward vs Reverse

Even a perfectly calibrated pipette will give poor results with the wrong technique. The two main approaches are:

• Forward pipetting: the standard method. Press to the first stop to aspirate, then to the second stop to fully expel. Suited to most aqueous solutions.
• Reverse pipetting: aspirate past the first stop, then dispense only to the first stop, leaving a small residual in the tip. This compensates for liquid clinging to the tip and is the correct method for viscous, foaming, or volatile liquids.

Pre-wetting the tip, holding the pipette vertically during aspiration, and matching the immersion depth to the volume all measurably improve accuracy. These small habits separate reproducible labs from ones that chase phantom variability.

Common Mistakes When Choosing or Using a Pipette

After 70 years of supplying Australian laboratories, we see the same avoidable errors again and again:

• Using an air-displacement pipette for viscous or volatile liquids. The air cushion makes the volume wrong before the sample even leaves the tip. Switch to positive displacement.
• Skipping calibration. A pipette that feels fine can be well outside its tolerance. Without a calibration schedule, you are guessing at your own accuracy.
• Pipetting at the extreme low end of the range. A 1000 microlitre pipette set to 20 microlitres is far less accurate than a 20 microlitre pipette. Match the pipette to the volume.
• Mismatched tips. Off-brand or poorly fitting tips break the air seal and ruin accuracy. Tip fit is part of the measurement system, not an accessory.
• Ignoring temperature. Cold or warm liquids, and a pipette straight from a cold room, shift the air cushion and the density of the sample.
• Buying on price alone. A cheap pipette with no local calibration or service support costs far more over its life in failed results and downtime.

Australian Standards and Compliance

For Australian laboratories, pipette accuracy is governed by several overlapping standards:

• ISO 8655: Piston-operated volumetric apparatus. Defines test methods and maximum permissible errors for mechanical pipettes.
• ISO 648: One-mark (volumetric) glass pipettes, including Class A and Class B tolerances.
• ISO 835: Graduated glass pipettes.
• ISO/IEC 17025: The basis for NATA accreditation, requiring traceable calibration of measuring equipment.
• TGA and GMP requirements: Pharmaceutical and medical-device laboratories must maintain documented calibration and verification of liquid-handling equipment.

Frequently Asked Questions

What is a pipette?
A pipette is a laboratory instrument used to measure and transfer a precise volume of liquid. Volumes range from fractions of a microlitre to tens of millilitres, and accuracy depends on the pipette type, its calibration status, and the operator's technique.

What is the difference between air displacement and positive displacement pipettes?
Air-displacement pipettes use an air cushion between the piston and the liquid and suit standard aqueous samples. Positive-displacement pipettes place the piston in direct contact with the liquid, eliminating the air gap, which makes them the correct choice for viscous, volatile, or dense liquids.

How often should a pipette be calibrated?
As a general rule, every 3 to 6 months, with more frequent calibration for high-use pipettes or critical and regulated applications. Under NATA accreditation, calibration must be traceable and documented. The interval should be set by your quality system.

What is a multichannel pipette used for?
A multichannel pipette dispenses into multiple wells at once, typically 8, 12, or 16 channels, and is used for microplate assays, ELISA, PCR setup, and other array-based work where speed and consistency across many samples matter.

What is the difference between forward and reverse pipetting?
Forward pipetting is the standard method for aqueous solutions. Reverse pipetting leaves a small residual in the tip and is used for viscous, foaming, or volatile liquids, where it gives better accuracy.

What is the difference between Class A and Class B volumetric pipettes?
Class A glass volumetric pipettes are manufactured to tighter tolerances and are the standard for analytical and regulated work. Class B pipettes have roughly double the permissible error and are suited to teaching and non-critical use.

How much does a pipette cost?
Pipette pricing depends on the type and volume range. Entry-level manual single-channel pipettes are the most affordable, electronic and multichannel models cost more, and glass volumetric pipettes are inexpensive but require a controller. Because price varies by model and quantity, the most accurate option is to request a current quote for the specific pipette and volume you need.

How much does pipette calibration cost in Australia?
The cost of NATA-accredited pipette calibration depends on the number of pipettes, channels, and turnaround required, and on whether the work is done on-site or in the lab. Request a quote for your fleet, and factor calibration into the total cost of ownership rather than the purchase price alone.

How do I choose between pipette brands?
Look past the badge at three things: the accuracy and repeatability specification against ISO 8655, the availability of local calibration and service support, and the fit for your sample type. A pipette with no local service or calibration costs more over its life in downtime and failed results, even if it is cheaper to buy. John Morris Group supplies Gilson, the recognised PIPETMAN range, backed by Australian service and NATA-accredited calibration.

Where can I buy pipettes in Australia?
John Morris Group supplies Gilson PIPETMAN, Microman, and multichannel pipettes, along with Cole-Parmer liquid handling, and provides NATA-accredited pipette calibration. Call 1300 501 555 or browse our laboratory supplies.