diff --git a/components/mucus.js b/components/mucus.js
index f2d643d855b51fd3bfe55cb0d3725a6e96b53816..4c75148f330085a82dc04918c8889f25c1c60a9f 100644
--- a/components/mucus.js
+++ b/components/mucus.js
@@ -12,6 +12,7 @@ import {
   mucusFeeling as feelingLabels,
   mucusTexture as textureLabels
 } from '../labels/labels'
+import computeSensiplanValue from '../lib/sensiplan-mucus'
 
 export default class Mucus extends Component {
   constructor(props) {
@@ -137,11 +138,11 @@ export default class Mucus extends Component {
                 saveMucus(this.cycleDay, {
                   feeling: this.state.currentFeelingValue,
                   texture: this.state.currentTextureValue,
+                  computedValue: computeSensiplanValue(this.state.currentFeelingValue, this.state.currentTextureValue),
                   exclude: this.state.exclude
                 })
                 this.showView('dayView')
               }}
-              // FIXME: find out how disabled works when 2 values need to be checked
               disabled={ this.state.currentFeelingValue === -1 || this.state.currentTextureValue === -1 }
               title="Save">
             </Button>
diff --git a/lib/sensiplan-mucus.js b/lib/sensiplan-mucus.js
new file mode 100644
index 0000000000000000000000000000000000000000..27e1590eb59f9799012f4a841973d90f0107d2a6
--- /dev/null
+++ b/lib/sensiplan-mucus.js
@@ -0,0 +1,16 @@
+export default function (feeling, texture) {
+  const feelingMapping = {
+    0: 0,
+    1: 1,
+    2: 2,
+    3: 4
+  }
+  const textureMapping = {
+    0: 0,
+    1: 3,
+    2: 4
+  }
+  const nfpFeelingValue = feelingMapping[feeling]
+  const nfpTextureValue = textureMapping[texture]
+  return Math.max(nfpFeelingValue, nfpTextureValue)
+}
diff --git a/test/sensiplan-mucus.spec.js b/test/sensiplan-mucus.spec.js
new file mode 100644
index 0000000000000000000000000000000000000000..feb4e93df4b441dceaeed0a2e1505a7830bd183a
--- /dev/null
+++ b/test/sensiplan-mucus.spec.js
@@ -0,0 +1,80 @@
+import chai from 'chai'
+import dirtyChai from 'dirty-chai'
+
+const expect = chai.expect
+chai.use(dirtyChai)
+
+import getSensiplanMucus from '../lib/sensiplan-mucus'
+
+describe.only('getSensiplanMucus', () => {
+
+  describe('results in t for:', () => {
+    it('dry feeling and no texture', function () {
+      const sensiplanValue = getSensiplanMucus(0, 0)
+      expect(sensiplanValue).to.eql(0)
+    })
+  })
+
+  describe('results in Ø for:', () => {
+    it('no feeling and no texture', function () {
+      const sensiplanValue = getSensiplanMucus(1, 0)
+      expect(sensiplanValue).to.eql(1)
+    })
+  })
+
+  describe('results in f for:', () => {
+    it('wet feeling and no texture', function () {
+      const sensiplanValue = getSensiplanMucus(2, 0)
+      expect(sensiplanValue).to.eql(2)
+    })
+  })
+
+  describe('results in S for:', () => {
+    it('dry feeling and creamy texture', function () {
+      const sensiplanValue = getSensiplanMucus(0, 1)
+      expect(sensiplanValue).to.eql(3)
+    })
+
+    it('no feeling and creamy texture', function () {
+      const sensiplanValue = getSensiplanMucus(1, 1)
+      expect(sensiplanValue).to.eql(3)
+    })
+
+    it('wet feeling and creamy texture', function () {
+      const sensiplanValue = getSensiplanMucus(2, 1)
+      expect(sensiplanValue).to.eql(3)
+    })
+  })
+
+  describe('results in +S for:', () => {
+    it('dry feeling and egg white texture', function () {
+      const sensiplanValue = getSensiplanMucus(0, 2)
+      expect(sensiplanValue).to.eql(4)
+    })
+
+    it('no feeling and egg white texture', function () {
+      const sensiplanValue = getSensiplanMucus(1, 2)
+      expect(sensiplanValue).to.eql(4)
+    })
+
+    it('wet feeling and egg white texture', function () {
+      const sensiplanValue = getSensiplanMucus(2, 2)
+      expect(sensiplanValue).to.eql(4)
+    })
+
+    it('slippery feeling and egg white texture', function () {
+      const sensiplanValue = getSensiplanMucus(3, 2)
+      expect(sensiplanValue).to.eql(4)
+    })
+
+    it('slippery feeling and creamy texture', function () {
+      const sensiplanValue = getSensiplanMucus(3, 1)
+      expect(sensiplanValue).to.eql(4)
+    })
+
+    it('slippery feeling and no texture', function () {
+      const sensiplanValue = getSensiplanMucus(3, 0)
+      expect(sensiplanValue).to.eql(4)
+    })
+  })
+})