diff --git a/README.md b/README.md
index 1bf403b..b897f34 100644
--- a/README.md
+++ b/README.md
@@ -44,6 +44,10 @@ Base URL: http://stats.filspark.com/
 
   http://stats.filspark.com/participants/monthly
 
+- `GET /participants/accumulative/daily?from=<day>&to=<day>`
+
+  http://stats.filspark.com/participants/accumulative/daily
+
 - `GET /participants/change-rates?from=<day>&to=<day>`
 
   http://stats.filspark.com/participants/change-rates
diff --git a/stats/lib/platform-routes.js b/stats/lib/platform-routes.js
index 3bb17a0..574240e 100644
--- a/stats/lib/platform-routes.js
+++ b/stats/lib/platform-routes.js
@@ -7,7 +7,8 @@ import {
   fetchTopEarningParticipants,
   fetchParticipantsWithTopMeasurements,
   fetchDailyStationMeasurementCounts,
-  fetchParticipantsSummary
+  fetchParticipantsSummary,
+  fetchAccumulativeDailyParticipantCount
 } from './platform-stats-fetchers.js'
 
 const createRespondWithFetchFn = (pathname, searchParams, res) => (pgPool, fetchFn) => {
@@ -40,6 +41,8 @@ export const handlePlatformRoutes = async (req, res, pgPools) => {
     await respond(pgPools.stats, fetchTopEarningParticipants)
   } else if (req.method === 'GET' && url === '/participants/summary') {
     await respondWithParticipantsSummary(res, pgPools)
+  } else if (req.method === 'GET' && url === '/participants/accumulative/daily') {
+    await respond(pgPools.evaluate, fetchAccumulativeDailyParticipantCount)
   } else if (req.method === 'GET' && url === '/transfers/daily') {
     await respond(pgPools.stats, fetchDailyRewardTransfers)
   } else {
diff --git a/stats/lib/platform-stats-fetchers.js b/stats/lib/platform-stats-fetchers.js
index 5d77456..30c96ec 100644
--- a/stats/lib/platform-stats-fetchers.js
+++ b/stats/lib/platform-stats-fetchers.js
@@ -98,6 +98,33 @@ export const fetchDailyRewardTransfers = async (pgPool, filter) => {
   return Object.values(days)
 }
 
+/**
+ * @param {Queryable} pgPool
+ * @param {import('./typings.js').DateRangeFilter} filter
+ */
+export const fetchAccumulativeDailyParticipantCount = async (pgPool, filter) => {
+  const { rows } = await pgPool.query(`
+    WITH first_appearance AS (
+      SELECT participant_id, MIN(day) as day
+      FROM daily_participants
+      GROUP BY participant_id
+    ),
+    cumulative_participants AS (
+      SELECT
+        day,
+        COUNT(participant_id) OVER (ORDER BY day) AS cumulative_participants
+      FROM first_appearance
+    )
+    SELECT
+        DISTINCT(day::TEXT),
+        cumulative_participants::INT as participants
+    FROM cumulative_participants
+    WHERE day >= $1 AND day <= $2
+    ORDER BY day
+  `, [filter.from, filter.to])
+  return rows
+}
+
 /**
  * @param {Queryable} pgPool
  * @param {import('./typings.js').DateRangeFilter} filter
diff --git a/stats/test/platform-routes.test.js b/stats/test/platform-routes.test.js
index c7c37af..bf38a74 100644
--- a/stats/test/platform-routes.test.js
+++ b/stats/test/platform-routes.test.js
@@ -395,6 +395,57 @@ describe('Platform Routes HTTP request handler', () => {
       )
     })
   })
+
+  describe('GET /participants/accumulative/daily', () => {
+    it('counts accumulative daily participants', async () => {
+      // 3 new participants, out of range
+      await givenDailyParticipants(
+        pgPools.evaluate,
+        '1999-01-01',
+        ['0x10', '0x20', '0x30']
+      )
+      // 3 new participants, 1 old participant -> 6
+      await givenDailyParticipants(
+        pgPools.evaluate,
+        '2000-01-01',
+        ['0x1', '0x2', '0x3', '0x10']
+      )
+      // 0 new participants, 2 old participants
+      await givenDailyParticipants(
+        pgPools.evaluate,
+        '2000-01-02',
+        ['0x1', '0x2']
+      )
+      // 1 new participant, 1 old participant -> 7
+      await givenDailyParticipants(
+        pgPools.evaluate,
+        '2000-01-03',
+        ['0x1', '0x4']
+      )
+      // 1 new participant, out of range
+      await givenDailyParticipants(
+        pgPools.evaluate,
+        '2000-01-04',
+        ['0x5']
+      )
+
+      const res = await fetch(
+        new URL('/participants/accumulative/daily?from=2000-01-01&to=2000-01-03', baseUrl), {
+          redirect: 'manual'
+        }
+      )
+      await assertResponseStatus(res, 200)
+      const daily = await res.json()
+      assert.deepStrictEqual(daily, [
+        { day: '2000-01-01', participants: 6 },
+        { day: '2000-01-03', participants: 7 }
+      ])
+      assert.strictEqual(
+        res.headers.get('cache-control'),
+        'public, max-age=31536000, immutable'
+      )
+    })
+  })
 })
 
 const givenDailyMeasurementsSummary = async (pgPoolEvaluate, summaryData) => {