1diff --git a/DOCS.md b/DOCS.md
  2index 7725e02..62111bc 100644
  3--- a/DOCS.md
  4+++ b/DOCS.md
  5@@ -448,6 +448,17 @@
  6 @returns {number} 
  7 @constructor
  8 ```
  9+
 10+### SLN 
 11+
 12+```
 13+  Returns the straight-line depreciation of an asset for one period. The amount of the depreciation is constant during the depreciation period. 
 14+@param cost - The initial cost of the asset. 
 15+@param salvage - The value of an asset at the end of the depreciation. 
 16+@param life - The depreciation period determining the number of periods in the deprecation of the asset. 
 17+@returns {number} 
 18+@constructor
 19+```
 20 ## Info
 21 
 22 
 23diff --git a/TODO.md b/TODO.md
 24index d572dd7..1679a09 100644
 25--- a/TODO.md
 26+++ b/TODO.md
 27@@ -153,5 +153,4 @@ For example 64 tbs to a qt.
 28 * PV
 29 * RATE
 30 * RECEIVED
 31-* SLN
 32 * YIELD
 33diff --git a/dist/Formulas/AllFormulas.js b/dist/Formulas/AllFormulas.js
 34index 0b47e18..725c4e3 100644
 35--- a/dist/Formulas/AllFormulas.js
 36+++ b/dist/Formulas/AllFormulas.js
 37@@ -111,6 +111,7 @@ exports.DOLLARDE = Financial_1.DOLLARDE;
 38 exports.DOLLARFR = Financial_1.DOLLARFR;
 39 exports.EFFECT = Financial_1.EFFECT;
 40 exports.SYD = Financial_1.SYD;
 41+exports.SLN = Financial_1.SLN;
 42 var Statistical_1 = require("./Statistical");
 43 exports.AVERAGE = Statistical_1.AVERAGE;
 44 exports.AVERAGEA = Statistical_1.AVERAGEA;
 45diff --git a/dist/Formulas/Financial.js b/dist/Formulas/Financial.js
 46index ce37ff2..ff726c0 100644
 47--- a/dist/Formulas/Financial.js
 48+++ b/dist/Formulas/Financial.js
 49@@ -443,3 +443,23 @@ var SYD = function (cost, salvage, life, period) {
 50     return (cost - salvage) * (life - period + 1) * 2 / (life * (life + 1));
 51 };
 52 exports.SYD = SYD;
 53+/**
 54+ * Returns the straight-line depreciation of an asset for one period. The amount of the depreciation is constant during
 55+ * the depreciation period.
 56+ * @param cost - The initial cost of the asset.
 57+ * @param salvage - The value of an asset at the end of the depreciation.
 58+ * @param life - The depreciation period determining the number of periods in the deprecation of the asset.
 59+ * @returns {number}
 60+ * @constructor
 61+ */
 62+var SLN = function (cost, salvage, life) {
 63+    ArgsChecker_1.ArgsChecker.checkLength(arguments, 3, "SYD");
 64+    cost = TypeConverter_1.TypeConverter.firstValueAsNumber(cost);
 65+    salvage = TypeConverter_1.TypeConverter.firstValueAsNumber(salvage);
 66+    life = TypeConverter_1.TypeConverter.firstValueAsNumber(life);
 67+    if (life === 0) {
 68+        throw new Errors_1.DivZeroError("Function SLN parameter 3 cannot be zero.");
 69+    }
 70+    return (cost - salvage) / life;
 71+};
 72+exports.SLN = SLN;
 73diff --git a/src/Formulas/AllFormulas.ts b/src/Formulas/AllFormulas.ts
 74index a7fd134..a38810e 100644
 75--- a/src/Formulas/AllFormulas.ts
 76+++ b/src/Formulas/AllFormulas.ts
 77@@ -114,7 +114,8 @@ import {
 78   DOLLARDE,
 79   DOLLARFR,
 80   EFFECT,
 81-  SYD
 82+  SYD,
 83+  SLN
 84 } from "./Financial";
 85 import {
 86   AVERAGE,
 87@@ -367,5 +368,6 @@ export {
 88   KURT,
 89   INTERCEPT,
 90   FORECAST,
 91-  SYD
 92+  SYD,
 93+  SLN
 94 }
 95\ No newline at end of file
 96diff --git a/src/Formulas/Financial.ts b/src/Formulas/Financial.ts
 97index ec27be0..87b9f9f 100644
 98--- a/src/Formulas/Financial.ts
 99+++ b/src/Formulas/Financial.ts
100@@ -455,6 +455,28 @@ var SYD = function (cost, salvage, life, period) {
101   return (cost - salvage) * (life - period + 1) * 2 / (life * (life + 1));
102 };
103 
104+
105+/**
106+ * Returns the straight-line depreciation of an asset for one period. The amount of the depreciation is constant during
107+ * the depreciation period.
108+ * @param cost - The initial cost of the asset.
109+ * @param salvage - The value of an asset at the end of the depreciation.
110+ * @param life - The depreciation period determining the number of periods in the deprecation of the asset.
111+ * @returns {number}
112+ * @constructor
113+ */
114+var SLN = function (cost, salvage, life) {
115+  ArgsChecker.checkLength(arguments, 3, "SYD");
116+  cost = TypeConverter.firstValueAsNumber(cost);
117+  salvage = TypeConverter.firstValueAsNumber(salvage);
118+  life = TypeConverter.firstValueAsNumber(life);
119+  if (life === 0) {
120+    throw new DivZeroError("Function SLN parameter 3 cannot be zero.");
121+  }
122+  return (cost - salvage) / life;
123+};
124+
125+
126 export {
127   ACCRINT,
128   CUMPRINC,
129@@ -466,5 +488,6 @@ export {
130   DOLLARFR,
131   EFFECT,
132   PMT,
133-  SYD
134+  SYD,
135+  SLN
136 }
137\ No newline at end of file
138diff --git a/tests/Formulas/FinancialTest.ts b/tests/Formulas/FinancialTest.ts
139index a4f90cc..b4fce60 100644
140--- a/tests/Formulas/FinancialTest.ts
141+++ b/tests/Formulas/FinancialTest.ts
142@@ -9,7 +9,8 @@ import {
143   DOLLARFR,
144   EFFECT,
145   PMT,
146-  SYD
147+  SYD,
148+  SLN
149 } from "../../src/Formulas/Financial";
150 import {
151   DATE
152@@ -288,4 +289,20 @@ test("SYD", function() {
153   catchAndAssertEquals(function() {
154     SYD.apply(this, [10, 10, 10, 10, 10]);
155   }, ERRORS.NA_ERROR);
156-});
157\ No newline at end of file
158+});
159+
160+
161+test("SLN", function() {
162+  assertEquals(SLN(100, 22, 10), 7.80);
163+  assertEquals(SLN(22.99, 1, 1), 21.99);
164+  assertEquals(SLN(22.99, 1, -1), -21.99);
165+  catchAndAssertEquals(function() {
166+    SLN(39, 22, 0);
167+  }, ERRORS.DIV_ZERO_ERROR);
168+  catchAndAssertEquals(function() {
169+    SLN.apply(this, [10, 10]);
170+  }, ERRORS.NA_ERROR);
171+  catchAndAssertEquals(function() {
172+    SLN.apply(this, [10, 10, 10, 10]);
173+  }, ERRORS.NA_ERROR);
174+});
175diff --git a/tests/SheetFormulaTest.ts b/tests/SheetFormulaTest.ts
176index 301b23d..3fb0a7c 100644
177--- a/tests/SheetFormulaTest.ts
178+++ b/tests/SheetFormulaTest.ts
179@@ -727,6 +727,10 @@ test("Sheet SYD", function(){
180   assertFormulaEquals('=SYD(100, 22, 10, 3)', 11.345454545454546);
181 });
182 
183+test("Sheet SLN", function(){
184+  assertFormulaEquals('=SLN(100, 22, 10)', 7.80);
185+});
186+
187 
188 test("Sheet *", function(){
189   assertFormulaEquals('= 10 * 10', 100);