diff --git a/README.md b/README.md
index 79d553bf..76011e8a 100644
--- a/README.md
+++ b/README.md
@@ -138,6 +138,7 @@ The input's file paths and directory structure will be preserved in the [`dag-pb
 - `dirBuilder` (object): the options for the directory builder
   - `hamt` (object): the options for the HAMT sharded directory builder
     - bits (positive integer, defaults to `8`): the number of bits at each bucket of the HAMT
+- `progress` (function): a function that will be called with the byte length of chunks as a file is added to ipfs.
 
 ### Exporter
 
diff --git a/package.json b/package.json
index 843791d2..433303dd 100644
--- a/package.json
+++ b/package.json
@@ -51,6 +51,7 @@
     "pull-generate": "^2.2.0",
     "pull-zip": "^2.0.1",
     "rimraf": "^2.6.1",
+    "sinon": "^3.2.1",
     "split": "^1.0.1"
   },
   "dependencies": {
@@ -91,4 +92,4 @@
     "jbenet <juan@benet.ai>",
     "nginnever <ginneversource@gmail.com>"
   ]
-}
\ No newline at end of file
+}
diff --git a/src/builder/builder.js b/src/builder/builder.js
index c9647bce..1a5852f8 100644
--- a/src/builder/builder.js
+++ b/src/builder/builder.js
@@ -93,7 +93,12 @@ module.exports = function (createChunker, ipldResolver, createReducer, _options)
     pull(
       file.content,
       createChunker(options.chunkerOptions),
-      pull.map(chunk => new Buffer(chunk)),
+      pull.map(chunk => {
+        if (options.progress && typeof options.progress === 'function') {
+          options.progress(chunk.byteLength)
+        }
+        return new Buffer(chunk)
+      }),
       pull.map(buffer => new UnixFS('file', buffer)),
       pull.asyncMap((fileNode, callback) => {
         DAGNode.create(fileNode.marshal(), [], options.hashAlg, (err, node) => {
diff --git a/test/test-importer.js b/test/test-importer.js
index 4fedead2..3e40cc64 100644
--- a/test/test-importer.js
+++ b/test/test-importer.js
@@ -7,6 +7,7 @@ const extend = require('deep-extend')
 const chai = require('chai')
 chai.use(require('dirty-chai'))
 const expect = chai.expect
+const sinon = require('sinon')
 const BlockService = require('ipfs-block-service')
 const pull = require('pull-stream')
 const mh = require('multihashes')
@@ -417,6 +418,23 @@ module.exports = (repo) => {
           }
         }
       })
+
+      it('will call an optional progress function', (done) => {
+        options.progress = sinon.spy()
+
+        pull(
+          pull.values([{
+            path: '1.2MiB.txt',
+            content: pull.values([bigFile])
+          }]),
+          importer(ipldResolver, options),
+          pull.collect(() => {
+            expect(options.progress.called).to.equal(true)
+            expect(options.progress.args[0][0]).to.equal(1024)
+            done()
+          })
+        )
+      })
     })
   })
 }