diff --git a/src/cpmBucketManager.js b/src/cpmBucketManager.js
index 0061d35f483..c2250838bcb 100644
--- a/src/cpmBucketManager.js
+++ b/src/cpmBucketManager.js
@@ -100,7 +100,7 @@ function getCpmStringValue(cpm, config, granularityMultiplier) {
     }
   });
   if (bucket) {
-    cpmStr = getCpmTarget(cpm, bucket.increment, bucket.precision, granularityMultiplier);
+    cpmStr = getCpmTarget(cpm, bucket, granularityMultiplier);
   }
   return cpmStr;
 }
@@ -118,12 +118,17 @@ function isValidPriceConfig(config) {
   return isValid;
 }
 
-function getCpmTarget(cpm, increment, precision, granularityMultiplier) {
-  if (typeof precision === 'undefined') {
-    precision = _defaultPrecision;
-  }
-  let bucketSize = 1 / (increment * granularityMultiplier);
-  return (Math.floor(cpm * bucketSize) / bucketSize).toFixed(precision);
+function getCpmTarget(cpm, bucket, granularityMultiplier) {
+  const precision = typeof bucket.precision !== 'undefined' ? bucket.precision : _defaultPrecision;
+  const increment = bucket.increment * granularityMultiplier;
+  const bucketMin = bucket.min * granularityMultiplier;
+
+  // start increments at the bucket min and then add bucket min back to arrive at the correct rounding
+  let cpmTarget = ((Math.floor((cpm - bucketMin) / increment)) * increment) + bucketMin;
+  // force to 10 decimal places to deal with imprecise decimal/binary conversions
+  //    (for example 0.1 * 3 = 0.30000000000000004)
+  cpmTarget = Number(cpmTarget.toFixed(10));
+  return cpmTarget.toFixed(precision);
 }
 
 export { getPriceBucketString, isValidPriceConfig };
diff --git a/test/spec/cpmBucketManager_spec.js b/test/spec/cpmBucketManager_spec.js
index e5e2d03c66c..3d56299ebfd 100644
--- a/test/spec/cpmBucketManager_spec.js
+++ b/test/spec/cpmBucketManager_spec.js
@@ -35,6 +35,29 @@ describe('cpmBucketManager', () => {
     expect(JSON.stringify(output)).to.deep.equal(expected);
   });
 
+  it('gets the correct custom bucket strings with irregular increment', () => {
+    let cpm = 14.50908;
+    let customConfig = {
+      'buckets': [{
+        'precision': 4,
+        'min': 0,
+        'max': 4,
+        'increment': 0.01,
+      },
+      {
+        'precision': 4,
+        'min': 4,
+        'max': 18,
+        'increment': 0.3,
+        'cap': true
+      }
+      ]
+    };
+    let expected = '{"low":"5.00","med":"14.50","high":"14.50","auto":"14.50","dense":"14.50","custom":"14.5000"}';
+    let output = getPriceBucketString(cpm, customConfig);
+    expect(JSON.stringify(output)).to.deep.equal(expected);
+  });
+
   it('gets the correct custom bucket strings in non-USD currency', () => {
     let cpm = 16.50908 * 110.49;
     let customConfig = {