ICCA recorded more than 11,000 international association meetings in 2024. Browse their names and you will find congresses, conferences, symposia, conventions, summits and annual meetings, often for events of almost identical size. Ex Ordo, a software provider that manages abstract submissions for conferences and symposia, states plainly that “there is no universal definition of a symposium or a conference”. Choosing a label therefore means deciding what expectations to set.
That choice shapes decisions made by people beyond your organising team. A researcher decides whether to submit a single paper or a full panel. A sponsor decides whether there will be an exhibition floor. And a head of department, reading the invitation in a member’s inbox, decides whether the trip is worth approving. Each uses the event name to judge what to expect from the programme. This guide sets out what each term usually promises, compares them in one table, and helps you choose the label that matches the event you are actually planning.
Conference, congress, symposium, convention: the short answer
A conference is a multi-session meeting on a broad theme, usually with parallel tracks and individual submissions. A congress is a large, often international conference of an association or scientific society, typically held annually or every few years and rotating between cities. A symposium is a smaller, single-topic meeting where invited experts present and discuss, often as grouped panels. A convention is a large membership gathering, common in North America, that combines sessions, business meetings and an exhibition.
As a rule of thumb, the label tells people more about the programme and opportunities to meet than about attendance numbers.
The comparison table
Most guides compare two of these terms at a time. In practice, programme committees weigh all four at once, so here they are side by side. The figures are typical ranges observed in association and academic events, not formal thresholds; no standards body sets them.
| Criterion | Conference | Congress | Symposium | Convention |
|---|---|---|---|---|
| Typical size | 100 to 2,000 | 500 to 10,000 or more | 30 to 300 | 1,000 to 50,000 or more |
| Duration | 1 to 3 days | 3 to 5 days | Half a day to 2 days | 3 to 5 days |
| Who it is for | Professionals across a field, often open registration | Members of an association or society plus international guests | Specialists in one narrow topic, often invited | Members of an association or industry, plus exhibitors |
| Programme logic | Plenary plus parallel tracks on related themes | Plenary, many parallel sessions, posters, satellite symposia | One room, one topic, presentations followed by discussion | General sessions, education tracks, business meetings, exhibition |
| Call for papers | Open call, individual abstracts reviewed one by one | Open call at scale, with a scientific committee and abstract book | Often invited, or grouped panel submissions reviewed together | Calls for session proposals rather than research papers |
| Networking and meeting share | Medium: breaks, receptions, some scheduled meetings | Medium to high: exhibition, society meetings, side events | High per person: small group, long discussion | High: exhibition floor, delegations, business meetings |
| Typical rhythm | Annual or one-off | Annual, biennial or triennial, rotating venue | One-off, or embedded in a larger event | Annual, often in the same few cities |
Two rows are particularly useful: programme structure and the call for papers. Together, they tell you more than size alone. A 200-person event with an open call and three parallel tracks is a conference, even if it is small. A 600-person event with one room and invited speakers on one question behaves like a symposium, whatever it says on the badge.
How the event name shapes expectations
The event name helps prospective attendees understand how the programme works. If it suggests something different from what you offer, even interested participants may arrive with the wrong expectations.
Picture a medical society that calls its new one-day meeting a symposium, then opens it to everyone and runs three parallel rooms. Senior specialists arrive expecting a focused discussion with peers. They find a crowded foyer and 15-minute slots. Some may decide not to return, even if the event was well run, because the programme did not match their expectations.
The reverse happens too. An engineering association renames its annual meeting a convention to sound bigger. Exhibitors now expect an exhibition hall and ask for floor plans. Members expect a trade show atmosphere. The programme committee spends the spring explaining that there is no hall. The new name has created months of avoidable clarification.
The same logic reaches the person who approves the trip. A congress invitation signals international peers, a scientific programme and a rotating host city, which is easy to justify as professional development. A symposium invitation signals depth on one topic, which works when the topic matches the member’s job exactly. A label that fits the programme makes that approval easier.
The four terms in more detail
Here is what each term commonly means in practice.
What is a conference?
A conference is the broadest of the four labels. It covers one field or theme and splits it into sessions, often in parallel tracks so attendees can build their own path. Contributions usually arrive through an open call for papers or speakers, and each abstract is reviewed on its own merit. Business conferences, academic conferences and member conferences all use the word, which is exactly why it is the safest default when nothing else fits. If you are building the timetable for one, our guide to planning a conference agenda that leaves time for networking covers the session grid in detail.
What is a congress?
In Europe and in international science, a congress is the flagship meeting of an association or society. It is large, scientific in tone, and usually rotates between host cities on an annual or multi-year cycle. ICCA, the International Congress and Convention Association, only counts a meeting if it rotates between at least three countries, attracts at least 50 participants on site and takes place at a regular frequency. Most congresses meet those criteria comfortably. Typical ingredients are plenary lectures, dozens of parallel sessions, poster sessions, satellite symposia funded by industry, an exhibition and the society’s own business meetings.
What is a symposium?
The word comes from the Greek symposion, a drinking party where guests talked philosophy late into the night. Today, the term refers to a focused exchange of specialist knowledge. A symposium focuses on one narrow topic, gathers a small group of experts and leaves real time for discussion after each presentation. Ex Ordo describes the defining structural difference well: conference papers are submitted and reviewed individually, while symposium papers are often submitted as a group and accepted or rejected together. Symposia can stand alone or sit inside a larger congress as one session type.
What is a convention?
Convention is the North American counterpart of the European congress, with a stronger commercial and membership flavour. Professional associations and industries hold annual conventions that combine education sessions, general assemblies, award ceremonies and large exhibitions. Delegations, often from local chapters, are a defining feature. Outside the United States, the word appears mainly in venue names (“convention centre”) and in the trade’s own vocabulary.
Related formats: summit, seminar and workshop
Three related labels often join the mix. A summit promises senior, invitation-led attendance and a few big topics. A seminar is a teaching format with one or two trainers and a fixed learning goal. A workshop produces a defined output, such as a draft or a decision, in a small working group. If your programme contains small discussion formats inside a larger event, our guide to running a roundtable discussion at a B2B conference shows how table size and seating change the result.
How big are these events really?
Size is the criterion people reach for first, so it helps to see what the data says. The answer is less dramatic than the word “congress” suggests.
International association meetings
Most congresses are mid-sized
ICCA’s 2024 data shows that most international association meetings have between 150 and 999 participants. In other words, a typical “international congress” is the size of a mid-sized conference. If you are planning a 400-person event, size alone will not decide the label for you. The programme structure is the more useful guide.
Regional usage: congress, convention and the German Tagung
The same event can carry different names depending on where it is held and who organises it. Language habits explain a lot of the confusion.
In continental Europe and in medicine, “congress” is the standard word for a society’s main scientific meeting. In the United States, the same event is more likely to be an “annual meeting” or a “convention”, while “congress” sounds political. In the United Kingdom, “conference” is the everyday default for almost everything. In German-speaking countries, a fourth word enters the mix: “Tagung”, which describes a professional meeting of a defined group, often members of one association, and is usually smaller and less formal than a Kongress.
For international audiences this matters. If you run an association event in Vienna with delegates from North America and Asia, the English title should match what your target audience searches for and what their employers recognise. “Annual Congress” reads well in Europe. “Annual Meeting” may travel better in the United States. When in doubt, add a descriptive subtitle that states the programme logic in plain words.
Which label fits your format? A decision guide
The comparison table describes typical events. The decision guide below works the other way round: you start with your format and arrive at the label. Answer the five questions in order.
Decision guide
Five questions that pick the right label
- Question 1 How many people, how many rooms? One room and under 300 people points to a symposium. Several parallel rooms point to a conference or congress.
- Question 2 Who attends? Members of one society meeting internationally suggests a congress. A broad professional audience suggests a conference. Members plus exhibitors suggests a convention.
- Question 3 How is the programme built? One question discussed in depth is a symposium. Many related themes in tracks are a conference or congress.
- Question 4 How does content enter? Invited experts or grouped panels fit a symposium. An open call with individual abstract review fits a conference or congress. Session proposals fit a convention.
- Question 5 How much of the event is meetings? If exhibition and business meetings carry the event, convention fits. If scheduled peer meetings are central, say so in the subtitle, whatever the label.
Mixed answers are normal. A congress with an embedded symposium is a common and perfectly coherent structure. The test is whether each part of the event keeps the promise its own label makes.
If you run several formats across the year, the label question becomes a portfolio question. Our guide to association event management shows how the annual meeting, the congress and regional days can work as one programme, with each event given a clear job. And once your format involves an open call at scale, the tooling changes: the guide to conference management software explains why the submission and review round is the real dividing line between systems.
Where networking fits in each format
The last row of the comparison table is the one most organisers underrate. Alongside the sessions, the people attendees can meet often help justify the trip. Those approving travel may also want to know which useful contacts resulted.
Each format handles that differently. At a symposium, networking happens almost by itself: 60 specialists sharing one room have plenty of opportunities to talk. At a congress with 4,000 delegates, the opposite is true. The colleague working on exactly the same problem may sit three halls away for four days. Without a clear meeting structure, even a large event can offer surprisingly few relevant encounters per person.
That is where scheduled one-to-one meetings change the economics of a large event. Converve lets organisers set rules in a configurable meeting matrix: which member groups, specialties, regions or exhibitor categories may meet whom, and in which time slots. The logic stays transparent and under the programme committee’s control. For associations, our solution for associations shows how this works alongside a congress or annual meeting.
The label sets the expectation. The meeting structure delivers it.
Frequently Asked Questions
What is a symposium?
A symposium is a meeting focused on one narrow topic, where a small group of experts present and then discuss their work. Symposia usually last half a day to two days, take place in a single room and often use invited speakers or grouped panel submissions. They can stand alone or run as a session inside a larger congress.
What is the difference between a symposium and a conference?
A conference covers a broad field with many sessions, often in parallel tracks, and reviews each submitted abstract individually. A symposium covers one topic in one room and often accepts papers as a group. Ex Ordo, which manages submissions for both formats, describes this submission logic as the core structural difference (Ex Ordo, 2026).
What is the difference between a conference and a convention?
A convention is typically larger and more commercial. It brings together members of an association or industry for sessions, business meetings and a sizeable exhibition. A conference is primarily about content and discussion. The word convention is mostly used in North America.
Is a congress bigger than a conference?
Usually, but not by definition. A congress is typically the main international meeting of an association or society, rotating between host cities. ICCA data for 2024 shows that most international association meetings have 150 to 999 participants (ICCA GlobeWatch 2024), so many congresses are no bigger than a mid-sized conference.
What is a summit?
A summit is an event that promises senior attendance and a small number of big topics, usually with invited participants and a high share of discussion. The word signals level rather than format, so it works best when the guest list genuinely supports it.
Conclusion: name the programme you are actually running
Conference, congress, symposium and convention are not size categories. They set expectations about how the programme is developed, who speaks, who attends and how people meet. A label that matches your format helps attract suitable contributions, sponsors and delegates. A name chosen mainly for its impact may require repeated explanations.
Start with the five questions in the decision guide, check the result against the comparison table and write a subtitle that states the format in plain words. Then make sure the meeting structure delivers what the label promises, especially at large events where the right people will not find each other by chance. Want to see how scheduled meetings work at congresses and association events? Get in touch with Converve.
