What is the difference between a pipette and a burette?
A pipette transfers a measured volume of liquid from one container to another, while a burette delivers a variable, controlled volume through a stopcock, usually drop by drop, and is used mainly for titrations. In short, a pipette is for moving a set amount, and a burette is for measuring how much liquid was needed to reach a result.
How each instrument works
A pipette is a narrow glass or plastic tube. You draw liquid into it by suction, a bulb or a pipette filler, hold it with a fingertip or valve, and then release the liquid into the receiving vessel. Some pipettes are made for one fixed volume, others are graduated so you can choose a volume.
A burette is a long, uniform glass tube with a graduated scale, normally 25 or 50 ml in capacity, and a stopcock or valve at the bottom. It is clamped upright on a stand and filled from the top. You open the stopcock to let liquid run into a flask below, and you read the level before and after. The difference between the two readings is the delivered volume.
Main differences at a glance
| Feature | Pipette | Burette |
|---|---|---|
| Main purpose | Transferring a measured volume | Delivering a variable volume, mainly in titration |
| Volume | Fixed (volumetric) or chosen from a scale (graduated) | Any volume within the scale, read as a difference |
| Control | Fingertip, valve or filler | Stopcock, allowing single drops |
| Typical capacity | 0.1 to 100 ml | 10, 25 or 50 ml |
| Position in use | Held by hand, vertical | Clamped on a stand |
| Reading | One mark or a scale | Two readings, start and end |
Accuracy and reading technique
Both instruments are calibrated at a stated temperature, usually 20 degrees Celsius, and both are read at the bottom of the meniscus with the eye level with the liquid surface. A class A volumetric pipette has a very small tolerance, often a few hundredths of a millilitre for a 10 ml size. A class A 50 ml burette is typically accurate to about 0.05 ml, which matters because the end point of a titration is judged from tiny volume changes.
The burette is not more precise than every pipette. It earns its place because it lets you add liquid in very small steps and stop at exactly the right moment, something a pipette cannot do.
When to use which
- Use a pipette to measure out a sample, such as 25 ml of an unknown solution, into a conical flask.
- Use a burette to add the titrant until an indicator changes colour or an instrument signals the end point.
- Use a graduated pipette when you need several different volumes and moderate accuracy is enough.
- Use a volumetric pipette when you need one volume repeated with the best accuracy.
In a typical titration the two work together: the pipette places an exact volume of sample in the flask, and the burette adds reagent until the reaction is complete.
Common mistakes
With burettes, the usual errors are leaving an air bubble in the tip, forgetting to fill the space below the stopcock, and reading from the top of the meniscus. With pipettes, people often blow out the last drop of a pipette that is not designed for it, or touch the tip to the wrong surface. Always rinse with a small amount of the liquid you will measure, and check that glassware is clean enough for water to drain in an even film.
Česta pitanja
Can a pipette replace a burette in a titration?
Not properly. A pipette cannot add small increments at will, so you would overshoot the end point or need many repeated transfers. A burette is built for this job.
Is a burette more accurate than a pipette?
Not necessarily. A volumetric pipette is usually more accurate for a single fixed volume. A burette is better because it is adjustable and lets you stop at a precise point.
What does the stopcock do?
It opens and closes the outlet so liquid runs out at a controlled rate, from a steady stream down to single drops.
Choosing droppers for your product
Dropper pipettes on a product bottle are a different tool from laboratory pipettes. They are not calibrated to deliver a certified volume. They are built to dispense liquid by drops or small squeezes, with a glass pipette, a rubber or TPE teat and a collar that screws onto a DIN18 bottle. Packaging.si assembles these droppers in Slovenia and supplies matching amber glass bottles from 5 to 100 ml.
