CONSORT diagram generator for randomized trials

What a CONSORT flow diagram is

CONSORT (Consolidated Standards of Reporting Trials) is the reporting guideline for randomized trials. Its flow diagram shows how participants moved through each phase of a trial: how many were assessed for eligibility and excluded, how many were randomized to each group, how many received the allocated intervention, how many were lost to follow-up or discontinued, and how many were included in the analysis of the primary outcome. Readers use it to judge attrition and to check that the analysis matches the randomized groups.

• CONSORT 2025 was published on April 14, 2025, simultaneously in BMJ, JAMA, The Lancet, Nature Medicine, and PLOS Medicine. It updates CONSORT 2010 and comes with a 30-item checklist and a flow diagram template.
• The ICMJE Recommendations name CONSORT as the reporting guideline for randomized trials. Whether a flow diagram is mandatory is set by each journal, so check the instructions for authors of your target journal.
• The official template is drawn for a two-group trial. For three or four arms, add a parallel column per arm, as this consort flow diagram tool does.

What changed in the CONSORT 2025 flow diagram

Comparing the official 2010 and 2025 templates, the four stages (Enrollment, Allocation, Follow-Up, Analysis) and the order of the boxes are the same. The visible wording change is that follow-up and analysis now refer to the primary outcome: "Lost to follow-up" became "Lost to follow-up for primary outcome", and "Analysed" became "Analysed for primary outcome". This generator uses the 2025 labels, in US or UK spelling. If your journal still asks for the 2010 wording, edit the text in the exported SVG, which keeps every label as editable text.

How to fill in each box

• Assessed for eligibility: everyone screened against the eligibility criteria.
• Excluded: people screened but not randomized, split into not meeting inclusion criteria, declined to participate, and other reasons. The three counts should add up to the excluded total.
• Randomized: participants who were randomly assigned. It should equal assessed minus excluded.
• Allocated to intervention: everyone assigned to each arm, whether or not they received it. Arm totals should add up to the randomized count. Below it, record how many received the allocated intervention and how many did not, with reasons.
• Follow-up: participants lost to follow-up for the primary outcome and participants who discontinued the intervention, each with reasons. People who stop treatment can still attend outcome visits and be analyzed, so discontinuations are not automatically subtracted from the analysis box.
• Analysis: participants analyzed for the primary outcome in each arm, and those excluded from the analysis with reasons. When every allocated participant is accounted for, analyzed plus excluded from analysis equals allocated.

Common mistakes the checker catches

Most problems in a randomized controlled trial flow diagram are arithmetic slips and missing reasons. The tool checks both as you type and shows warnings instead of blocking the diagram, because real trials have legitimate complexities such as participants randomized in error or withdrawals of consent for data use.

• Numbers that do not add up: assessed minus excluded differs from randomized, arm totals differ from the randomized count, received plus did not receive differs from allocated, or reasons do not sum to their box total.
• Unaccounted participants: analyzed plus excluded from analysis does not equal the number allocated to the arm, or more people are analyzed than were allocated.
• Missing reasons: a nonzero count of exclusions, losses, discontinuations, or analysis exclusions with no reasons listed. The 2025 template asks for reasons in each of these boxes.
• Mixing up discontinued and lost to follow-up. Someone who stopped the intervention but completed the outcome assessment is not lost to follow-up.
• When a warning reflects a real feature of your trial, write an override note. Print it under the diagram, or keep it for your records and explain it in the manuscript.

CONSORT vs PRISMA flow diagrams

Both are flow diagrams, but they count different things. A CONSORT diagram follows people through one randomized trial. A PRISMA 2020 flow diagram follows information through a systematic review: the records identified, screened, included, and excluded, and the reasons for exclusion. If you are writing up a systematic review or meta-analysis of trials, you need a PRISMA diagram, not a CONSORT diagram. Use CONSORT when you report the results of the trial itself.

Export for your manuscript

The consort diagram template renders in a plain journal style: Arial text, thin black boxes, and black arrows, with an optional accent color for the side stage labels. Export an SVG to edit in a vector editor, or a PNG that is 2,400 pixels wide, which is 300 DPI across 8 inches (203 mm). Save the form as a JSON file to reopen it during revisions; a draft is also kept in this browser's local storage so a page refresh does not lose your counts. Everything in this consort diagram generator runs client-side, so you can prepare the figure for a blinded or unpublished trial without sending any counts to a server.