Logo of the Physikalisch-Technische Bundesanstalt

Easy Read Information

PTB stands for “Physikalisch-Technische Bundesanstalt”. These German words mean “physical-technical federal institute”.

Physics studies the properties of matter and radiation.

Physics researchers are called “physicists”.

They try to understand nature through experiments.

They need a lot of technical equipment for these experiments.

That is why researchers often have to build complex instruments and machines.

A federal institute is a large institution.

It handles tasks that are important for all citizens.

PTB is called a “research institute” because people do research at PTB.

PTB has a large site with a lot of buildings.

There is a large PTB site in Braunschweig.

There is also a small PTB site in Berlin.

The number of people who work at PTB in Braunschweig is 1500.

The number of people who work at PTB in Berlin is 400.

PTB deals with measuring.

Almost everyone has a measurement device on hand: a clock.

A clock measures time.

We have many measurement devices in our daily lives.

We use them to measure weight, length and temperature, for example.

People at PTB know everything about measuring.

Tasks of PTB


PTB’s task is to measure things accurately.

PTB’s task is to research everything about measuring.

PTB’s task is written down in a law.

The most famous measurement devices of PTB are its atomic clocks.

They are at PTB in Braunschweig.

Atomic clocks are the most accurate clocks in the world.

PTB researchers are making them even more accurate.

PTB also tests measurement devices for industry.

PTB also tests many everyday devices.

PTB doesn’t test every single device, just one of each kind.

The difficult word for that is “prototype”. A prototype is the first version of a product.

PTB tests prototypes of fuel pumps, supermarket scales, electricity meters and many other measurement devices.

If they measure well enough, PTB gives them a good report. The report is called a “certificate”.

PTB works together with researchers from all over the world.

That is why everyone in the world uses the same measurement units.

One meter in Germany is thus exactly the same length as a one meter in Japan.

PTB also supports development.

It helps other countries that want to have their own PTB.

PTB has been doing all these tasks for over 125 years.



Measurement in our daily lives

Imagine that you are lying in bed. Now you are just waking up.

Your alarm clock woke you up.

It is a radio alarm clock.

It gets the time from PTB’s atomic clocks.

You get out of bed. You are still tired.

You would like to make a pot of coffee.

You pour water into the coffee machine.

You measured the right amount of water before that.

Your coffee is brewing now. You want to get dressed.

Is your thin sweater warm enough for today? You take a look at the thermometer.

It shows the temperature.

Every measurement device measures things in measurement units.

For example, time is measured using a clock.

The unit is called “second”.

Temperatures are measured using a thermometer.

The unit is called “degree Celsius”.

We often don’t notice the measurements at all.

A water meter, for example, measures how much water we use.

An electricity meter measures how much electricity we use.

And a gas meter measures how much gas a heating system uses.

PTB makes sure that measurement devices measure accurately and reliably.

Otherwise it would be a mess.


All the parts of a machine need to fit together perfectly.

But parts often come from different factories all over the world.

That is why manufacturers must measure them regularly.

The measurements tell them if every screw fits perfectly. They make sure there are no mistakes.

But measurement devices can also make mistakes.

That is why PTB tests these types of measuring devices.

Here’s another example: Our computers and mobile phones are getting better and better.

Chips are built into the inside of computers and mobile phones.

The chips are made up of tiny parts.

They need to be assembled very accurately.

Measurement devices make sure that everything fits.

PTB, on the other hand, tests the measurement devices.

Without PTB there would be no accurate measuring.

PTB makes sure that measuring is more and more accurate.

That is why PTB is a research institute.

[Translate to English:] Navigation

The logo of the Physikalisch-Technische Bundesanstalt.

The logo is in the same place on every PTB page.
Clicking on the logo takes you to the start page.

The internet page has 5 sections:

  1. the header
  2. the main menu
  3. the page menu
  4. the page content


The header is at the top of the page.The header contains the logo and accessibility settings.

Main menu

In the main menu, all pages of the website are listed.If you click on the name of a page, the page is shown.The main menu has 6 sections.The sections of the main menu are:

  • Research & Development
  • Metrological Services
  • International Affairs
  • Press & What's New
  • About us & Careers
  • Structure & Divisions

Page menu
The page menu is on the left-hand side.
In the page menu are the sub-pages of a page.

Page content

The information of the page is in the main section of the website.
For example, news or information about scientists can be found here.

The footer is at the bottom of the web page.
The footer contains links from the main menu.
In the footer are pictures and links from other research institutions.
The PTB cooperates with these research institutions.


PTB is always there when you use a radio clock.

PTB will also be there next time you put fruit on a scale.

Please come visit us on Open Day.

Just ask when the next Open Day is.

Or ask us if you can join a group of visitors.

Secretariat of Press and Information Office

Karin Conring

Phone: (0531) 592-3006
Fax: (0531) 592-3008

Email: karin.conring(at)ptb.de


Bundesallee 100
38116 Braunschweig

Animated Video: Units in Everyday Life