diff --git a/src/PhpSpreadsheet/Calculation/Financial.php b/src/PhpSpreadsheet/Calculation/Financial.php
index 3cb6d40a52..401e9f1bfb 100644
--- a/src/PhpSpreadsheet/Calculation/Financial.php
+++ b/src/PhpSpreadsheet/Calculation/Financial.php
@@ -1873,43 +1873,55 @@ public static function PV($rate = 0, $nper = 0, $pmt = 0, $fv = 0, $type = 0)
      */
     public static function RATE($nper, $pmt, $pv, $fv = 0.0, $type = 0, $guess = 0.1)
     {
-        $nper = (int) Functions::flattenSingleValue($nper);
+        $nper = Functions::flattenSingleValue($nper);
         $pmt = Functions::flattenSingleValue($pmt);
         $pv = Functions::flattenSingleValue($pv);
         $fv = ($fv === null) ? 0.0 : Functions::flattenSingleValue($fv);
         $type = ($type === null) ? 0 : (int) Functions::flattenSingleValue($type);
         $guess = ($guess === null) ? 0.1 : Functions::flattenSingleValue($guess);
+        $maxIter = 0;
 
+        $epsilon = self::FINANCIAL_PRECISION;
         $rate = $guess;
-        if (abs($rate) < self::FINANCIAL_PRECISION) {
-            $y = $pv * (1 + $nper * $rate) + $pmt * (1 + $rate * $type) * $nper + $fv;
-        } else {
-            $f = exp($nper * log(1 + $rate));
-            $y = $pv * $f + $pmt * (1 / $rate + $type) * ($f - 1) + $fv;
-        }
-        $y0 = $pv + $pmt * $nper + $fv;
-        $y1 = $pv * $f + $pmt * (1 / $rate + $type) * ($f - 1) + $fv;
-
-        // find root by secant method
-        $i = $x0 = 0.0;
-        $x1 = $rate;
-        while ((abs($y0 - $y1) > self::FINANCIAL_PRECISION) && ($i < self::FINANCIAL_MAX_ITERATIONS)) {
-            $rate = ($y1 * $x0 - $y0 * $x1) / ($y1 - $y0);
-            $x0 = $x1;
-            $x1 = $rate;
-            if (($nper * abs($pmt)) > ($pv - $fv)) {
-                $x1 = abs($x1);
-            }
-            if (abs($rate) < self::FINANCIAL_PRECISION) {
-                $y = $pv * (1 + $nper * $rate) + $pmt * (1 + $rate * $type) * $nper + $fv;
+        $found = false;
+        $geoSeries = $geoSeriesPrime = 0.0;
+        $term = $termPrime = 0.0;
+        $rateNew = 0.0;
+        $isInteger = false;
+
+        if ($nper === (int) round($nper)) {
+            $isInteger = true;
+        }
+
+        while (!$found && ++$maxIter <= self::FINANCIAL_MAX_ITERATIONS) {
+            if ($isInteger) {
+                $powNMinus1 = pow(1 + $rate, $nper - 1);
+                $powN = $powNMinus1 * (1 + $rate);
             } else {
-                $f = exp($nper * log(1 + $rate));
-                $y = $pv * $f + $pmt * (1 / $rate + $type) * ($f - 1) + $fv;
+                $powNMinus1 = pow(1 + $rate, $nper);
+                $powN = pow(1 + $rate, $nper);
             }
 
-            $y0 = $y1;
-            $y1 = $y;
-            ++$i;
+            if ($rate == 0) {
+                $geoSeries = $nper;
+                $geoSeriesPrime = $nper * (($nper - 1) / 2.0);
+            } else {
+                $geoSeries = ($powN - 1) / $rate;
+                $geoSeriesPrime = $nper * $powNMinus1 / $rate - ($geoSeries / $rate);
+            }
+            $term = $fv + $pv * $powN + $pmt * $geoSeries;
+            $termPrime = $pv * $nper * $powNMinus1 + $pmt * $geoSeriesPrime;
+            if (abs($term) < $epsilon) {
+                $found = true;
+            } else {
+                if ($termPrime == 0) { //will catch root which is at an extreme
+                    $rateNew = $rate + 1.1 * $epsilon;
+                } else {
+                    $rateNew = $rate - $term / $termPrime;
+                }
+            }
+            $found = abs($rateNew - $rate) < $epsilon;
+            $rate = $rateNew;
         }
 
         return $rate;
diff --git a/tests/PhpSpreadsheetTests/Calculation/FinancialTest.php b/tests/PhpSpreadsheetTests/Calculation/FinancialTest.php
index d9103896cb..345a9e32f8 100644
--- a/tests/PhpSpreadsheetTests/Calculation/FinancialTest.php
+++ b/tests/PhpSpreadsheetTests/Calculation/FinancialTest.php
@@ -518,7 +518,7 @@ public function providerPV()
      */
     public function testRATE($expectedResult, ...$args)
     {
-        $this->markTestIncomplete('TODO: This test should be fixed');
+//        $this->markTestIncomplete('TODO: This test should be fixed');
 
         $result = Financial::RATE(...$args);
         self::assertEquals($expectedResult, $result, null, 1E-8);
diff --git a/tests/data/Calculation/Financial/RATE.php b/tests/data/Calculation/Financial/RATE.php
index 20f5397afc..cc183566a3 100644
--- a/tests/data/Calculation/Financial/RATE.php
+++ b/tests/data/Calculation/Financial/RATE.php
@@ -28,7 +28,13 @@
         5000,
     ],
     [
-        0.016550119066711999,
+        0.017929869399484,
+        24.99,
+        -250,
+        5000
+    ],
+    [
+        0.01513084390231,
         24,
         -250,
         5000,