diff --git a/libs/report/committers/src/lib/committers-monthly.spec.ts b/libs/report/committers/src/lib/committers-monthly.spec.ts
new file mode 100644
index 0000000..8bf56c2
--- /dev/null
+++ b/libs/report/committers/src/lib/committers-monthly.spec.ts
@@ -0,0 +1,94 @@
+import { parseMonthly } from './parse-monthly';
+
+describe('parseMonthly', () => {
+  const sampleCommits = [
+    {
+      date: new Date('2023-01-15T12:00:00Z'),
+      committer: 'Marco',
+      commitHash: 'abc123',
+    },
+    {
+      date: new Date('2023-01-20T12:00:00Z'),
+      committer: 'Marco',
+      commitHash: 'def456',
+    },
+    {
+      date: new Date('2023-02-10T12:00:00Z'),
+      committer: 'George',
+      commitHash: 'ghi789',
+    },
+    {
+      date: new Date('2023-02-15T12:00:00Z'),
+      committer: 'Marco',
+      commitHash: 'jkl012',
+    },
+  ];
+
+  it('should group commits by month and count them per committer', () => {
+    const start = new Date('2023-01-01T00:00:00Z');
+    const end = new Date('2023-03-01T00:00:00Z');
+    const result = parseMonthly(start, end, sampleCommits);
+
+    expect(result).toEqual([
+      {
+        month: 'January 2023',
+        start,
+        end,
+        committers: {
+          Marco: 2,
+        },
+      },
+      {
+        month: 'February 2023',
+        start,
+        end,
+        committers: {
+          George: 1,
+          Marco: 1,
+        },
+      },
+    ]);
+  });
+
+  it('should return an empty array if there are no commits', () => {
+    const result = parseMonthly(
+      new Date('2023-01-01T00:00:00Z'),
+      new Date('2023-03-01T00:00:00Z'),
+      []
+    );
+    expect(result).toEqual([]);
+  });
+
+  it('should handle date ranges with no commits in certain months', () => {
+    const commits = [
+      {
+        date: new Date('2023-03-10T12:00:00Z'),
+        committer: 'Greg',
+        commitHash: 'mno345',
+      },
+    ];
+    const start = new Date('2023-01-01T00:00:00Z');
+    const end = new Date('2023-04-01T00:00:00Z');
+    const result = parseMonthly(start, end, commits);
+
+    expect(result).toEqual([
+      {
+        month: 'March 2023',
+        start,
+        end,
+        committers: {
+          Greg: 1,
+        },
+      },
+    ]);
+  });
+
+  it('should handle an empty date range', () => {
+    const result = parseMonthly(
+      new Date('2023-01-01T00:00:00Z'),
+      new Date('2023-01-01T00:00:00Z'),
+      sampleCommits
+    );
+    expect(result).toEqual([]);
+  });
+});
diff --git a/libs/report/committers/src/lib/committers.ts b/libs/report/committers/src/lib/committers.ts
index 71f00d8..5f6462d 100644
--- a/libs/report/committers/src/lib/committers.ts
+++ b/libs/report/committers/src/lib/committers.ts
@@ -6,6 +6,11 @@ import { parseGitLogEntries } from './parse-git-log-entries';
 import { getCommitterCounts } from './get-committer-counts';
 import { ArgumentsCamelCase, CommandBuilder, CommandModule } from 'yargs';
 import { CommitterCount } from './types';
+import {
+  outputMonthlyCommitters,
+  outputMonthlyCommittersJson,
+  parseMonthly,
+} from './parse-monthly';
 
 interface Options {
   beforeDate: string;
@@ -13,6 +18,7 @@ interface Options {
   exclude: string[];
   json: boolean;
   directory: string;
+  monthly: boolean;
 }
 
 export const reportCommittersCommand: CommandModule<object, Options> = {
@@ -50,6 +56,13 @@ export const reportCommittersCommand: CommandModule<object, Options> = {
       required: false,
       string: true,
     },
+    monthly: {
+      alias: 'm',
+      boolean: true,
+      describe: 'Break down by calendar month, rather than by committer.',
+      required: false,
+      default: false,
+    },
   } as CommandBuilder<unknown, Options>,
   handler: run,
 };
@@ -80,6 +93,17 @@ async function run(args: ArgumentsCamelCase<Options>): Promise<void> {
     return;
   }
   const entries = parseGitLogEntries(rawEntries);
+
+  if (args.monthly) {
+    const monthly = parseMonthly(afterDate, beforeDate, entries);
+    if (args.json) {
+      outputMonthlyCommittersJson(monthly);
+      return;
+    }
+    outputMonthlyCommitters(monthly);
+    return;
+  }
+
   const committerCounts = getCommitterCounts(entries);
   if (args.json) {
     outputCommittersJson(committerCounts);
diff --git a/libs/report/committers/src/lib/parse-monthly.ts b/libs/report/committers/src/lib/parse-monthly.ts
index a6de2ae..23e59af 100644
--- a/libs/report/committers/src/lib/parse-monthly.ts
+++ b/libs/report/committers/src/lib/parse-monthly.ts
@@ -1,24 +1,13 @@
-import {
-  eachMonthOfInterval,
-  format,
-  isWithinInterval,
-  max,
-  min,
-} from 'date-fns';
-import { MonthlyData } from './types';
+import { eachMonthOfInterval, format, isWithinInterval } from 'date-fns';
+import { Commit, MonthlyData } from './types';
 
-export function parseMonthly(
-  startDate: Date,
-  endDate: Date,
-  entries: { commitHash: string; committer: string; date: string }[]
-) {
+export function parseMonthly(startDate: Date, endDate: Date, entries: Commit[]) {
   const monthly: MonthlyData[] = [];
-  const dates = [startDate, endDate];
-  const ival = {
-    start: min(dates),
-    end: max(dates),
-  };
-  const range = eachMonthOfInterval(ival);
+  const range = eachMonthOfInterval({
+    start: startDate,
+    end: endDate,
+  });
+
   for (const idxr in range) {
     const idx = parseInt(idxr);
     if (idx + 1 >= range.length) {
@@ -26,19 +15,15 @@ export function parseMonthly(
     }
     const [start, end] = [range[idx], range[idx + 1]];
     const month: MonthlyData = {
-      name: format(start, 'LLLL yyyy'),
-      start,
-      end,
+      month: format(start, 'LLLL yyyy'),
+      start: startDate,
+      end: endDate,
       committers: {},
     };
 
     for (const rec of entries) {
-      if (isWithinInterval(new Date(rec.date), { start, end })) {
-        month.committers[rec.committer] = month.committers[rec.committer] || [];
-        month.committers[rec.committer].push({
-          hash: rec.commitHash,
-          date: rec.date,
-        });
+      if (isWithinInterval(rec.date, { start, end })) {
+        month.committers[rec.committer] = (month.committers[rec.committer] || 0) + 1;
       }
     }
 
@@ -48,3 +33,20 @@ export function parseMonthly(
   }
   return monthly;
 }
+
+function monthlyDataHumanReadable(data: MonthlyData) {
+  return {
+    ...data,
+    start: format(data.start, 'yyyy-MM-dd'),
+    end: format(data.end, 'yyyy-MM-dd'),
+  };
+}
+
+export function outputMonthlyCommitters(commits: MonthlyData[]) {
+  const mapped = commits.map((c) => monthlyDataHumanReadable(c));
+  console.table(mapped);
+}
+
+export function outputMonthlyCommittersJson(commits: MonthlyData[]) {
+  console.log(JSON.stringify(commits, null, 2));
+}
diff --git a/libs/report/committers/src/lib/types.ts b/libs/report/committers/src/lib/types.ts
index ac69cd5..18ab597 100644
--- a/libs/report/committers/src/lib/types.ts
+++ b/libs/report/committers/src/lib/types.ts
@@ -9,10 +9,10 @@ export type CommitterCount = {
 };
 
 export type MonthlyData = {
-  name: string;
+  month: string;
   start: Date;
   end: Date;
-  committers: Record<string, { hash: string; date: string }[]>;
+  committers: Record<string, number>;
 };
 
 export type SortedCommitterInfo = {