diff --git a/prometheus_client/openmetrics/parser.py b/prometheus_client/openmetrics/parser.py
index 5ddcd26c..6df2afad 100644
--- a/prometheus_client/openmetrics/parser.py
+++ b/prometheus_client/openmetrics/parser.py
@@ -6,6 +6,7 @@
 
 from ..metrics_core import Metric, METRIC_LABEL_NAME_RE
 from ..samples import Exemplar, Sample, Timestamp
+from ..utils import floatToGoString
 
 try:
     import StringIO
@@ -371,7 +372,7 @@ def build_metric(name, documentation, typ, unit, samples):
                 allowed_names = {
                     'counter': ['_total', '_created'],
                     'summary': ['_count', '_sum', '', '_created'],
-                    'histogram': ['_count', '_sum', '_bucket', 'created'],
+                    'histogram': ['_count', '_sum', '_bucket', '_created'],
                     'gaugehistogram': ['_gcount', '_gsum', '_bucket'],
                     'info': ['_info'],
                 }.get(typ, [''])
@@ -402,10 +403,12 @@ def build_metric(name, documentation, typ, unit, samples):
             if typ == 'stateset' and name not in sample.labels:
                 raise ValueError("Stateset missing label: " + line)
             if (typ in ['histogram', 'gaugehistogram'] and name + '_bucket' == sample.name
-                    and float(sample.labels.get('le', -1)) < 0):
+                    and (float(sample.labels.get('le', -1)) < 0
+                         or sample.labels['le'] != floatToGoString(sample.labels['le']))):
                 raise ValueError("Invalid le label: " + line)
             if (typ == 'summary' and name == sample.name
-                    and not (0 <= float(sample.labels.get('quantile', -1)) <= 1)):
+                    and (not (0 <= float(sample.labels.get('quantile', -1)) <= 1)
+                         or sample.labels['quantile'] != floatToGoString(sample.labels['quantile']))):
                 raise ValueError("Invalid quantile label: " + line)
 
             g = tuple(sorted(_group_for_sample(sample, name, typ).items()))
diff --git a/prometheus_client/utils.py b/prometheus_client/utils.py
index 1b9c1733..4f0c5108 100644
--- a/prometheus_client/utils.py
+++ b/prometheus_client/utils.py
@@ -5,6 +5,7 @@
 
 
 def floatToGoString(d):
+    d = float(d)
     if d == INF:
         return '+Inf'
     elif d == MINUS_INF:
@@ -12,4 +13,11 @@ def floatToGoString(d):
     elif math.isnan(d):
         return 'NaN'
     else:
-        return repr(float(d))
+        s = repr(d)
+        dot = s.find('.')
+        # Go switches to exponents sooner than Python.
+        # We only need to care about positive values for le/quantile.
+        if d > 0 and dot > 6:
+            mantissa = '{}.{}{}'.format(s[0], s[1:dot], s[dot+1:]).rstrip('0.')
+            return '{}e+0{}'.format(mantissa, dot-1)
+        return s
diff --git a/tests/openmetrics/test_parser.py b/tests/openmetrics/test_parser.py
index 681cfe33..544a41c4 100644
--- a/tests/openmetrics/test_parser.py
+++ b/tests/openmetrics/test_parser.py
@@ -98,50 +98,50 @@ def test_summary_quantiles(self):
     def test_simple_histogram(self):
         families = text_string_to_metric_families("""# TYPE a histogram
 # HELP a help
-a_bucket{le="1"} 0
+a_bucket{le="1.0"} 0
 a_bucket{le="+Inf"} 3
 a_count 3
 a_sum 2
 # EOF
 """)
-        self.assertEqual([HistogramMetricFamily("a", "help", sum_value=2, buckets=[("1", 0.0), ("+Inf", 3.0)])], list(families))
+        self.assertEqual([HistogramMetricFamily("a", "help", sum_value=2, buckets=[("1.0", 0.0), ("+Inf", 3.0)])], list(families))
 
     def test_histogram_exemplars(self):
         families = text_string_to_metric_families("""# TYPE a histogram
 # HELP a help
-a_bucket{le="1"} 0 # {a="b"} 0.5
-a_bucket{le="2"} 2 # {a="c"} 0.5
+a_bucket{le="1.0"} 0 # {a="b"} 0.5
+a_bucket{le="2.0"} 2 # {a="c"} 0.5
 a_bucket{le="+Inf"} 3 # {a="1234567890123456789012345678901234567890123456789012345678"} 4 123
 # EOF
 """)
         hfm = HistogramMetricFamily("a", "help")
-        hfm.add_sample("a_bucket", {"le": "1"}, 0.0, None, Exemplar({"a": "b"}, 0.5))
-        hfm.add_sample("a_bucket", {"le": "2"}, 2.0, None, Exemplar({"a": "c"}, 0.5)),
+        hfm.add_sample("a_bucket", {"le": "1.0"}, 0.0, None, Exemplar({"a": "b"}, 0.5))
+        hfm.add_sample("a_bucket", {"le": "2.0"}, 2.0, None, Exemplar({"a": "c"}, 0.5)),
         hfm.add_sample("a_bucket", {"le": "+Inf"}, 3.0, None, Exemplar({"a": "1234567890123456789012345678901234567890123456789012345678"}, 4, Timestamp(123, 0)))
         self.assertEqual([hfm], list(families))
 
     def test_simple_gaugehistogram(self):
         families = text_string_to_metric_families("""# TYPE a gaugehistogram
 # HELP a help
-a_bucket{le="1"} 0
+a_bucket{le="1.0"} 0
 a_bucket{le="+Inf"} 3
 a_gcount 3
 a_gsum 2
 # EOF
 """)
-        self.assertEqual([GaugeHistogramMetricFamily("a", "help", gsum_value=2, buckets=[("1", 0.0), ("+Inf", 3.0)])], list(families))
+        self.assertEqual([GaugeHistogramMetricFamily("a", "help", gsum_value=2, buckets=[("1.0", 0.0), ("+Inf", 3.0)])], list(families))
 
     def test_gaugehistogram_exemplars(self):
         families = text_string_to_metric_families("""# TYPE a gaugehistogram
 # HELP a help
-a_bucket{le="1"} 0 123 # {a="b"} 0.5
-a_bucket{le="2"} 2 123 # {a="c"} 0.5
+a_bucket{le="1.0"} 0 123 # {a="b"} 0.5
+a_bucket{le="2.0"} 2 123 # {a="c"} 0.5
 a_bucket{le="+Inf"} 3 123 # {a="d"} 4 123
 # EOF
 """)
         hfm = GaugeHistogramMetricFamily("a", "help")
-        hfm.add_sample("a_bucket", {"le": "1"}, 0.0, Timestamp(123, 0), Exemplar({"a": "b"}, 0.5))
-        hfm.add_sample("a_bucket", {"le": "2"}, 2.0, Timestamp(123, 0), Exemplar({"a": "c"}, 0.5)),
+        hfm.add_sample("a_bucket", {"le": "1.0"}, 0.0, Timestamp(123, 0), Exemplar({"a": "b"}, 0.5))
+        hfm.add_sample("a_bucket", {"le": "2.0"}, 2.0, Timestamp(123, 0), Exemplar({"a": "c"}, 0.5)),
         hfm.add_sample("a_bucket", {"le": "+Inf"}, 3.0, Timestamp(123, 0), Exemplar({"a": "d"}, 4, Timestamp(123, 0)))
         self.assertEqual([hfm], list(families))
 
@@ -383,11 +383,11 @@ def test_timestamps(self):
     def test_roundtrip(self):
         text = """# HELP go_gc_duration_seconds A summary of the GC invocation durations.
 # TYPE go_gc_duration_seconds summary
-go_gc_duration_seconds{quantile="0"} 0.013300656000000001
+go_gc_duration_seconds{quantile="0.0"} 0.013300656000000001
 go_gc_duration_seconds{quantile="0.25"} 0.013638736
 go_gc_duration_seconds{quantile="0.5"} 0.013759906
 go_gc_duration_seconds{quantile="0.75"} 0.013962066
-go_gc_duration_seconds{quantile="1"} 0.021383540000000003
+go_gc_duration_seconds{quantile="1.0"} 0.021383540000000003
 go_gc_duration_seconds_sum 56.12904785
 go_gc_duration_seconds_count 7476.0
 # HELP go_goroutines Number of goroutines that currently exist.
@@ -405,7 +405,7 @@ def test_roundtrip(self):
 process_cpu_seconds_total 29323.4
 # HELP process_virtual_memory_bytes Virtual memory size in bytes.
 # TYPE process_virtual_memory_bytes gauge
-process_virtual_memory_bytes 2478268416.0
+process_virtual_memory_bytes 2.478268416e+09
 # HELP prometheus_build_info A metric with a constant '1' value labeled by version, revision, and branch from which Prometheus was built.
 # TYPE prometheus_build_info gauge
 prometheus_build_info{branch="HEAD",revision="ef176e5",version="0.16.0rc1"} 1.0
@@ -413,12 +413,28 @@ def test_roundtrip(self):
 # TYPE prometheus_local_storage_chunk_ops counter
 prometheus_local_storage_chunk_ops_total{type="clone"} 28.0
 prometheus_local_storage_chunk_ops_total{type="create"} 997844.0
-prometheus_local_storage_chunk_ops_total{type="drop"} 1345758.0
+prometheus_local_storage_chunk_ops_total{type="drop"} 1.345758e+06
 prometheus_local_storage_chunk_ops_total{type="load"} 1641.0
 prometheus_local_storage_chunk_ops_total{type="persist"} 981408.0
 prometheus_local_storage_chunk_ops_total{type="pin"} 32662.0
 prometheus_local_storage_chunk_ops_total{type="transcode"} 980180.0
 prometheus_local_storage_chunk_ops_total{type="unpin"} 32662.0
+# HELP foo histogram Testing histogram buckets
+# TYPE foo histogram
+foo_bucket{le="0.0"} 0.0
+foo_bucket{le="1e-05"} 0.0
+foo_bucket{le="0.0001"} 0.0
+foo_bucket{le="0.1"} 8.0
+foo_bucket{le="1.0"} 10.0
+foo_bucket{le="10.0"} 17.0
+foo_bucket{le="100000.0"} 17.0
+foo_bucket{le="1e+06"} 17.0
+foo_bucket{le="1.55555555555552e+06"} 17.0
+foo_bucket{le="1e+23"} 17.0
+foo_bucket{le="+Inf"} 17.0
+foo_count 17.0
+foo_sum 324789.3
+foo_created 1.520430000123e+09
 # EOF
 """
         families = list(text_string_to_metric_families(text))
@@ -522,6 +538,7 @@ def test_invalid_input(self):
                 ('# TYPE a summary\na{quantile="foo"} 0\n# EOF\n'),
                 ('# TYPE a summary\na{quantile="1.01"} 0\n# EOF\n'),
                 ('# TYPE a summary\na{quantile="NaN"} 0\n# EOF\n'),
+                ('# TYPE a summary\na{quantile="1"} 0\n# EOF\n'),
                 ('# TYPE a histogram\na_bucket 0\n# EOF\n'),
                 ('# TYPE a gaugehistogram\na_bucket 0\n# EOF\n'),
                 ('# TYPE a stateset\na 0\n# EOF\n'),
@@ -538,6 +555,12 @@ def test_invalid_input(self):
                 ('# TYPE a gaugehistogram\na_gsum 1\n# EOF\n'),
                 ('# TYPE a histogram\na_count 1\na_bucket{le="+Inf"} 0\n# EOF\n'),
                 ('# TYPE a histogram\na_bucket{le="+Inf"} 0\na_count 1\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="1"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="9.999999999999999e+22"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="1.5555555555555201e+06"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="1e-04"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="1e+05"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
+                ('# TYPE a histogram\na_bucket{le="+INF"} 0\n# EOF\n'),
                 ('# TYPE a histogram\na_bucket{le="2"} 0\na_bucket{le="1"} 0\na_bucket{le="+Inf"} 0\n# EOF\n'),
                 ('# TYPE a histogram\na_bucket{le="1"} 1\na_bucket{le="2"} 1\na_bucket{le="+Inf"} 0\n# EOF\n'),
                 # Bad grouping or ordering.
diff --git a/tests/test_parser.py b/tests/test_parser.py
index b5b26355..94c8f6e8 100644
--- a/tests/test_parser.py
+++ b/tests/test_parser.py
@@ -305,7 +305,7 @@ def test_roundtrip(self):
 process_cpu_seconds_total 29323.4
 # HELP process_virtual_memory_bytes Virtual memory size in bytes.
 # TYPE process_virtual_memory_bytes gauge
-process_virtual_memory_bytes 2478268416.0
+process_virtual_memory_bytes 2.478268416e+09
 # HELP prometheus_build_info A metric with a constant '1' value labeled by version, revision, and branch from which Prometheus was built.
 # TYPE prometheus_build_info gauge
 prometheus_build_info{branch="HEAD",revision="ef176e5",version="0.16.0rc1"} 1.0
@@ -313,7 +313,7 @@ def test_roundtrip(self):
 # TYPE prometheus_local_storage_chunk_ops_total counter
 prometheus_local_storage_chunk_ops_total{type="clone"} 28.0
 prometheus_local_storage_chunk_ops_total{type="create"} 997844.0
-prometheus_local_storage_chunk_ops_total{type="drop"} 1345758.0
+prometheus_local_storage_chunk_ops_total{type="drop"} 1.345758e+06
 prometheus_local_storage_chunk_ops_total{type="load"} 1641.0
 prometheus_local_storage_chunk_ops_total{type="persist"} 981408.0
 prometheus_local_storage_chunk_ops_total{type="pin"} 32662.0