diff --git a/p2pool/data.py b/p2pool/data.py
index e8fe347cc..40281e94b 100644
--- a/p2pool/data.py
+++ b/p2pool/data.py
@@ -12,6 +12,28 @@
 from p2pool.bitcoin import data as bitcoin_data, script, sha256
 from p2pool.util import math, forest, pack
 
+def deserialize_bignum(str_, len_):
+    result = 0L
+    for idx in xrange(len_//8):
+        limb, str_ = pack.IntType(64).unpack(str_[:8]), str_[8:]
+        result += limb << (idx * 64)
+    if len_ & 4:
+        limb, str_ = pack.IntType(32).unpack(str_[:4]), str_[4:]
+        result += limb << ((len_ & ~7) * 8)
+    if len_ & 2:
+        limb, str_ = pack.IntType(16).unpack(str_[:2]), str_[2:]
+        result += limb << ((len_ & ~3) * 8)
+    if len_ & 1:
+        limb, str_ = pack.IntType(8).unpack(str_[:1]), str_[1:]
+        result += limb << ((len_ & ~1) * 8)
+    return result
+def parse_bip0034(coinbase):
+    _, opdata = script.parse(coinbase).next()
+    bignum = deserialize_bignum(opdata, len(opdata))
+    if ord(opdata[-1]) & 0x80:
+        bignum = -bignum
+    return (bignum,)
+
 # hashlink
 
 hash_link_type = pack.ComposedType([
diff --git a/p2pool/web.py b/p2pool/web.py
index 7a6eff8f6..381cfd8e6 100644
--- a/p2pool/web.py
+++ b/p2pool/web.py
@@ -218,7 +218,7 @@ def decent_height():
     web_root.putChild('recent_blocks', WebInterface(lambda: [dict(
         ts=s.timestamp,
         hash='%064x' % s.header_hash,
-        number=pack.IntType(24).unpack(s.share_data['coinbase'][1:4]) if len(s.share_data['coinbase']) >= 4 else None,
+        number=p2pool_data.parse_bip0034(s.share_data['coinbase'])[0],
         share='%064x' % s.hash,
     ) for s in node.tracker.get_chain(node.best_share_var.value, min(node.tracker.get_height(node.best_share_var.value), 24*60*60//node.net.SHARE_PERIOD)) if s.pow_hash <= s.header['bits'].target]))
     web_root.putChild('uptime', WebInterface(lambda: time.time() - start_time))