diff --git a/CHANGELOG.md b/CHANGELOG.md
index 08932ec..67316fa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 All notable changes to `ssl-certificate` will be documented in this file
 
+## 1.19.0 - 2020-03-21
+
+- add lifespan in days
+
 ## 1.18.0 - 2020-03-18
 
 - get details from a certificate from string (#123) 
diff --git a/README.md b/README.md
index 62a38d4..ed21560 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,9 @@ $certificate = SslCertificate::createFromString($certificateData);
 
 $certificate->getIssuer(); // returns "Let's Encrypt Authority X3"
 $certificate->isValid(); // returns true if the certificate is currently valid
-$certificate->expirationDate(); // returns an instance of Carbon
+$certificate->validFromDate(); // returns a Carbon instance Carbon
+$certificate->expirationDate(); // returns a Carbon instance Carbon
+$certificate->lifespanInDays(); // return the amount of days between  validFromDate and expirationDate
 $certificate->expirationDate()->diffInDays(); // returns an int
 $certificate->getSignatureAlgorithm(); // returns a string
 $certificate->getOrganization(); // returns the organization name when available
diff --git a/src/SslCertificate.php b/src/SslCertificate.php
index 9e89c56..5f34bcd 100644
--- a/src/SslCertificate.php
+++ b/src/SslCertificate.php
@@ -134,6 +134,11 @@ public function expirationDate(): Carbon
         return Carbon::createFromTimestampUTC($this->rawCertificateFields['validTo_time_t']);
     }
 
+    public function lifespanInDays(): int
+    {
+        return $this->validFromDate()->diffInDays($this->expirationDate());
+    }
+
     public function isExpired(): bool
     {
         return $this->expirationDate()->isPast();
diff --git a/tests/SslCertificateTest.php b/tests/SslCertificateTest.php
index e167bdc..778cd18 100644
--- a/tests/SslCertificateTest.php
+++ b/tests/SslCertificateTest.php
@@ -79,6 +79,12 @@ public function it_can_determine_the_expiration_date()
         $this->assertSame('2016-08-17 16:50:00', $this->certificate->expirationDate()->format('Y-m-d H:i:s'));
     }
 
+    /** @test */
+    public function it_can_determine_the_lifespan_in_days()
+    {
+        $this->assertEquals(90, $this->certificate->lifespanInDays());
+    }
+
     /** @test */
     public function it_can_determine_if_the_certificate_is_valid()
     {