CONSORT flow diagram generator
Type the numbers from your randomised trial (assessed for eligibility, excluded with reasons, randomised, then for each arm allocated, received the intervention, discontinued, lost to follow-up and analysed) and the generator draws the CONSORT flow diagram with the four stages (enrolment, allocation, follow-up, analysis) as you type. It checks that the counts add up, follows the box wording of the CONSORT 2025 template (or CONSORT 2010), handles two or three arms, and exports an editable SVG, a 300 or 600 dpi PNG and plain text.
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At a glance
| Template | CONSORT 2025 flow diagram (Hopewell et al., BMJ 2025, doi:10.1136/bmj-2024-081123); CONSORT 2010 wording as an option (doi:10.1136/bmj.c332) |
|---|---|
| Stages | Enrolment, allocation, follow-up, analysis |
| Arms | Two or three, named |
| Checks | Excluded + randomised = assessed; arms = randomised; received + not received = allocated; reasons = their box; analysed against allocated |
| Output | Editable SVG, PNG at 300 or 600 dpi with the DPI recorded, plain text |
| Runs in | Your web browser; nothing is uploaded |
| Price | Free, no account needed |
What it does
How to use the CONSORT flow diagram generator
- Enter enrolmentType how many people were assessed for eligibility, how many were excluded and why (not meeting the inclusion criteria, declined, other reasons) and how many were randomised.
- Fill in each armName each arm and enter allocated, received and did-not-receive counts, then the discontinuations and losses to follow-up, and the numbers analysed and excluded from analysis, with one reason per line as “reason: n”.
- Check and exportFix anything the checks flag, then download the SVG (editable in Illustrator, Inkscape or PowerPoint), a PNG at 300 or 600 dpi, or the text.
How it works
The diagram follows the flow diagram of the CONSORT 2025 statement, which replaced CONSORT 2010 and asks, for each group, for the numbers randomly assigned, receiving the intended intervention and analysed for the primary outcome (item 22a), and for losses and exclusions after randomisation with reasons (item 22b). It has four stages:
- Enrolment. Everyone assessed for eligibility; those excluded before randomisation, split into not meeting inclusion criteria, declined to participate and other reasons; and the number randomised. Assessed = excluded + randomised.
- Allocation. For each arm, the number allocated, how many received the allocated intervention and how many did not, with reasons. Allocated = received + did not receive, and the arms add up to the number randomised.
- Follow-up. For each arm, participants who discontinued the intervention and those lost to follow-up for the primary outcome, each with reasons. Someone who stops treatment but still attends the outcome assessment is discontinued, not lost.
- Analysis. For each arm, the number analysed for the primary outcome and the number excluded from the analysis, with reasons. Without imputation, analysed = allocated − lost to follow-up − excluded from analysis; with imputation or an intention-to-treat analysis of everyone randomised, analysed can equal allocated.
CONSORT 2010 used the same boxes with “Lost to follow-up” and “Analysed”; the template menu switches the wording. Counts left blank are drawn as “(n = )”, as in the official template, and a blank total is filled with the sum of its listed reasons. The checks warn but never block, because some designs (imputation, crossover, re-randomisation) legitimately break the simple sums.
Sources: Hopewell S, Chan AW, Collins GS, et al. CONSORT 2025 statement: updated guideline for reporting randomised trials. BMJ 2025;389:e081123, doi:10.1136/bmj-2024-081123. Schulz KF, Altman DG, Moher D. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ 2010;340:c332, doi:10.1136/bmj.c332.
Worked example: a two-arm CONSORT flow diagram
The generator’s example: a two-arm trial of an intervention against a comparator.
- Enrolment. 412 people were assessed for eligibility; 172 were excluded (118 did not meet the inclusion criteria, 41 declined, 13 for other reasons: 118 + 41 + 13 = 172), so 412 − 172 = 240 were randomised.
- Allocation. 120 were allocated to each arm (120 + 120 = 240). In the intervention arm 117 received it and 3 did not (2 withdrew consent before treatment, 1 became ineligible): 117 + 3 = 120. In the comparator arm 119 received it and 1 did not.
- Follow-up. Intervention: 6 discontinued the intervention (4 adverse events, 2 by choice) and 5 were lost to follow-up for the primary outcome (3 moved away, 2 missed the final visit). Comparator: 4 discontinued and 7 were lost (4 withdrew consent, 3 could not be contacted).
- Analysis. Intervention: 120 − 5 lost − 1 excluded (no baseline measurement) = 114 analysed. Comparator: 120 − 7 lost − 0 excluded = 113 analysed. The 6 and 4 who discontinued are still analysed, because their primary outcome was measured.
| Check | Intervention | Comparator |
|---|---|---|
| Allocated = received + did not receive | 120 = 117 + 3 | 120 = 119 + 1 |
| Analysed = allocated − lost − excluded | 114 = 120 − 5 − 1 | 113 = 120 − 7 − 0 |
| Reasons add up to their box | 4 + 2 = 6; 3 + 2 = 5 | 3 + 1 = 4; 4 + 3 = 7 |
Overall: assessed 412 = excluded 172 + randomised 240, and the arms 120 + 120 = 240 randomised.
Frequently asked questions
What is a CONSORT diagram?
A CONSORT diagram (CONSORT flow diagram) shows how participants moved through a randomised trial: how many were assessed for eligibility, excluded and randomised, then for each arm how many were allocated, received the intervention, discontinued or were lost to follow-up, and were analysed, with reasons at every step. It is part of the CONSORT reporting guideline for randomised trials.
Is a CONSORT flow diagram required?
Most medical journals that endorse CONSORT (including The BMJ, JAMA, The Lancet and the ICMJE journals) expect one in every report of a randomised trial: CONSORT 2025 item 22a asks for the participant flow, including a flow diagram. Check your journal’s instructions; many also ask for the completed CONSORT checklist.
How do I make a CONSORT flow diagram?
Collect the counts from your screening log and trial database, enter them stage by stage (enrolment, allocation, follow-up, analysis) with the reasons for each exclusion and loss, check that the numbers add up, and export the diagram as SVG or as a PNG at the resolution the journal asks for (300 dpi, or 600 dpi for line art).
What changed in the CONSORT 2025 flow diagram?
CONSORT 2025 replaced CONSORT 2010, and its flow diagram makes the primary outcome explicit: the follow-up box reports participants lost to follow-up for the primary outcome and the analysis box reports those analysed for the primary outcome. The stages and the enrolment and allocation boxes are as before. Use the template menu to switch to the 2010 wording if your journal still asks for it.
What is the difference between lost to follow-up and discontinued intervention?
Discontinued means the participant stopped the intervention (for example because of an adverse event) but may still have been assessed. Lost to follow-up means the primary outcome could not be measured (moved away, could not be contacted, withdrew consent). Only losses to follow-up and exclusions reduce the number analysed.
Should the number analysed equal the number randomised?
In an intention-to-treat analysis with imputation of missing outcomes, yes. Without imputation, analysed = allocated − lost to follow-up − excluded from analysis, and the diagram should show why each participant is missing. The generator flags arms where neither sum holds.
Can I make a CONSORT diagram for a three-arm trial?
Yes: choose 3 arms and name each one. Each arm gets its own allocation, follow-up and analysis boxes, aligned in columns, with the stage labels on the left. For cluster, crossover or factorial trials, adapt the boxes as the relevant CONSORT extension describes.
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