Burette vs Pipette

Burettes and pipettes are both long glass tubes for measuring liquids accurately, and both appear in every titration. It’s easy to mix them up at first. The key difference: a pipette delivers one fixed volume of liquid very accurately, while a burette delivers a variable volume and tells you exactly how much has come out. In a titration, the pipette measures what goes into the flask at the start; the burette measures how much is needed to react with it.

Quick comparison

Feature	Burette	Pipette (volumetric)
What it does	delivers any volume up to its capacity, measured by difference	delivers one fixed volume
Typical sizes	25 cm³ or 50 cm³	10.00, 20.00, 25.00 or 50.00 cm³
Markings	graduated scale, usually every 0.1 cm³, reading from 0 at the top	a single calibration mark on the upper stem
Control	a tap (stopcock) at the bottom allows dropwise addition	liquid drawn up with a pipette filler; released all at once
Typical uncertainty	about ±0.05 cm³ per reading, ±0.10 cm³ per titre	about ±0.03–0.06 cm³ for a 25 cm³ pipette (class-dependent)
Held in	a clamp and stand, vertically	the hand, during use
Role in titration	adds the titrant and measures the titre	measures the fixed volume of analyte into the flask

What a pipette does

A volumetric pipette (bulb pipette) has a bulge in the middle and a single ring near the top. When filled exactly to the ring and allowed to drain, it delivers one specific volume, such as 25.00 cm³, very accurately.

How to use it

1. Rinse the pipette with a little of the solution to be measured (not water), so that the solution isn’t diluted by drops left inside.
2. Using a pipette filler (never your mouth), draw the solution up above the mark.
3. Let the liquid fall slowly until the bottom of the meniscus sits exactly on the mark, reading at eye level.
4. Let it drain into the conical flask with the tip touching the inside of the flask.
5. Don’t blow out the last drop left in the tip; the pipette is calibrated to allow for it (unless it’s marked as a “blow-out” pipette).

Graduated pipettes

A graduated (measuring) pipette has a scale and can deliver varying volumes, like a small burette without a tap. It’s more flexible but less accurate than a volumetric pipette. Micropipettes with disposable tips deliver microlitre volumes in biology and analytical labs.

What a burette does

A burette is a long graduated tube with a tap at the bottom. It’s filled with the titrant and read before and after adding liquid. The difference between the readings is the volume delivered.

How to use it

1. Rinse with a little of the titrant, then fill (using a small funnel, which you then remove).
2. Run a little liquid through the tap to fill the tip and remove air bubbles.
3. Record the initial reading at eye level, from the bottom of the meniscus, to two decimal places (the second being 0 or 5).
4. Add titrant to the flask, swirling, drop by drop near the end point.
5. Record the final reading. Titre = final − initial.

Note that burette scales read downwards from 0.00 at the top, the opposite of a measuring cylinder.

Why a titration needs both

In a typical acid–base titration:

• The pipette puts an exact, known volume (say 25.00 cm³) of the unknown into the flask.
• The burette adds the standard solution until the indicator changes, and measures exactly how much was needed.

Both volumes go into the calculation, so both must be accurate. See acid–base titration and titration calculations.

Worked example: uncertainty

A titration uses a 25.00 cm³ pipette (±0.06 cm³) and gives a titre of 22.40 cm³ from a burette (±0.05 cm³ per reading).

• Pipette percentage uncertainty: 0.06 ÷ 25.00 × 100 = 0.24%
• Burette: two readings, so ±0.10 cm³; percentage = 0.10 ÷ 22.40 × 100 = 0.45%

Both are small compared with a 50 cm³ measuring cylinder, whose uncertainty for 25 cm³ might be ±0.5 cm³ (2%). That’s why cylinders aren’t used for accurate titration volumes. See volumetric glassware tolerances and measurement uncertainty practice problems.

Common mistakes

Pipette:

• Rinsing with water instead of the solution (dilutes it).
• Reading the top of the meniscus.
• Blowing out the final drop.
• Letting air bubbles into the bulb, which gives too small a volume.

Burette:

• Leaving the funnel in the top (drips alter the reading).
• Not removing the air bubble from the tip; if it escapes during the titration, the titre appears too large.
• Reading from above or below eye level (parallax error).
• Recording readings to one decimal place instead of two.
• Adding titrant too quickly and overshooting the end point.

See titration errors and measuring volume accurately.

Which should I use?

You need to…	Use
Put exactly 25.00 cm³ of a solution into a flask	volumetric pipette
Add a solution gradually until something happens, and know how much you added	burette
Measure several different small volumes accurately (e.g. making a dilution series)	burette or graduated pipette
Measure an approximate volume quickly (e.g. 10 cm³ of acid to dissolve a solid)	measuring cylinder
Make up a solution to an exact total volume	volumetric flask

A short history

The burette was developed in France in the late eighteenth and early nineteenth centuries for testing the strength of bleach and other industrial chemicals, and Joseph Louis Gay-Lussac improved its design. The German chemist Karl Friedrich Mohr later introduced the tap-controlled burette and the volumetric pipette, much like the ones used today. Their accuracy made titration one of the most important quantitative methods in chemistry. See volumetric analysis.

Digital alternatives

Modern labs increasingly use digital burettes (a motorised or hand-cranked piston with a digital display) and automatic titrators, which deliver titrant in tiny, precisely controlled steps. They remove reading errors, but the principle is exactly the same: a variable, measured volume of titrant.

Care and cleaning

• Rinse both with distilled water after use and store the burette upside down or filled with distilled water, as your lab directs.
• Never use a brush or abrasive inside a pipette; scratches affect the volume.
• Don’t heat volumetric glassware; expansion can change its calibration.
• Check burette taps for leaks before use.

Key takeaways

• A pipette delivers one fixed volume very accurately; a burette delivers a variable volume measured by difference.
• In a titration, the pipette measures the analyte into the flask and the burette measures the titrant added.
• Rinse each with the solution it will contain, read the bottom of the meniscus at eye level, and record burette readings to two decimal places.
• A burette titre involves two readings, so its uncertainty is about ±0.10 cm³.
• Both are far more accurate than measuring cylinders for quantitative work.