Clinical Trials Calendar 2026

A 2026 start date is a plan, not a fact

Every study on ClinicalTrials.gov has a start date, and each one is labelled either actual (it happened) or estimated (it's what the sponsor hopes). Most people never notice the label. It matters more than it looks.

On 28 September 2026 we counted every registered study, in any status, with a start date somewhere in 2026. Here's how those dates are holding up:

Look at January. 3,902 studies said they would start that month. Nine months later, 1,228 of them are still marked "not yet recruiting", and 1,465 still carry an estimated date rather than an actual one. That's more than a third of the month's studies with nothing confirmed. February, March and April look much the same.

The registry doesn't say why. Part of the gap can be a record that simply hasn't been updated yet, and part can be a study that really hasn't opened. From the outside you can't tell which, and that's exactly the problem if you're waiting on one. What the data does show is that only 72 of the January studies have been formally withdrawn. The rest are still listed, still undated, still "coming."

The further out you look, the softer the numbers get. Every October, November and December date is an estimate by definition, and 3,616 of September's 4,007 studies hadn't confirmed a start as the month was ending.

Checking a start date yourself takes a minute

1. Open the study on ClinicalTrials.gov and find Study Start. If it says (Estimated) and the date is already in the past, treat it as unconfirmed.
2. Check Last Update Posted. A record nobody has touched for a year tells you more about the study than the start date does.
3. Scroll to the locations list. A site marked Recruiting is the only real signal that someone near you can actually enrol. The overall status can be ahead of or behind what individual sites are doing.

Counts from the ClinicalTrials.gov API v2, all statuses, 28 September 2026. The calendar below is different: it only shows studies from ClinicalMetric's own recruiting feed, grouped by the start date on their record.