diff --git a/src/Buffer.test.ts b/src/Buffer.test.ts
index 6f417f8e..5a43a5fe 100644
--- a/src/Buffer.test.ts
+++ b/src/Buffer.test.ts
@@ -5,10 +5,11 @@
 
 import { assert } from 'chai';
 import { ITerminal } from './Types';
-import { Buffer, DEFAULT_ATTR } from './Buffer';
+import { Buffer, DEFAULT_ATTR, CHAR_DATA_CHAR_INDEX } from './Buffer';
 import { CircularList } from './common/CircularList';
 import { MockTerminal } from './utils/TestUtils.test';
 import { BufferLine } from './BufferLine';
+import { Terminal } from './Terminal';
 
 const INIT_COLS = 80;
 const INIT_ROWS = 24;
@@ -347,4 +348,153 @@ describe('Buffer', () => {
       assert.equal(str3, '😁a');
     });
   });
+  describe('stringIndexToBufferIndex', function(): void {
+    beforeEach(function(): void {
+      terminal = new Terminal({rows: 5, cols: 10});
+      const oldWrite: any = terminal.write.bind(terminal);
+      terminal.write = (s: string): void => {
+        oldWrite(s);
+        (terminal as any)._innerWrite();
+      }
+    });
+    function wholeString(terminal: ITerminal, range : {first: number, last: number}): string {
+      let result = '';
+      for (let i = range.first; i <= range.last; ++i) {
+        result += terminal.buffer.translateBufferLineToString(i, i == range.last);
+      }
+      return result;
+    }
+    it('multiline ascii', function(): void {
+      const input = 'This is ASCII text spanning multiple lines.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      for (let i = 0; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([(i/terminal.cols) | 0, i % terminal.cols], bufferIndex);
+      }
+    });
+    it('combining e\u0301 in a sentence', function(): void {
+      const input = 'Sitting in the cafe\u0301 drinking coffee.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      for (let i = 0; i < 19; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([(i/terminal.cols) | 0, i % terminal.cols], bufferIndex);
+      }
+      // string index 18 & 19 point to combining char e\u0301 ---> same buffer Index
+      assert.deepEqual(
+        terminal.buffer.stringIndexToBufferIndex(0, 18),
+        terminal.buffer.stringIndexToBufferIndex(0, 19));
+      // after the combining char every string index has an offset of -1
+      for (let i = 19; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i - 1)/terminal.cols) | 0, (i - 1) % terminal.cols], bufferIndex);
+      }
+    });
+    it('multiline combining e\u0301', function(): void {
+      const input = 'e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301e\u0301';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      // every buffer cell index contains 2 string indices 
+      for (let i = 0; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i >> 1)/terminal.cols) | 0, (i >> 1) % terminal.cols], bufferIndex);
+      }
+    });
+    it('surrogate char in a sentence', function(): void {
+      const input = 'The 𝄞 is a clef widely used in modern notation.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      for (let i = 0; i < 5; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([(i/terminal.cols) | 0, i % terminal.cols], bufferIndex);
+      }
+      // string index 4 & 5 point to surrogate char 𝄞 ---> same buffer Index
+      assert.deepEqual(
+        terminal.buffer.stringIndexToBufferIndex(0, 4),
+        terminal.buffer.stringIndexToBufferIndex(0, 5));
+      // after the combining char every string index has an offset of -1
+      for (let i = 5; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i - 1)/terminal.cols) | 0, (i - 1) % terminal.cols], bufferIndex);
+      }
+    });
+    it('multiline surrogate char', function(): void {
+      const input = '𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞𝄞';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      // every buffer cell index contains 2 string indices 
+      for (let i = 0; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i >> 1)/terminal.cols) | 0, (i >> 1) % terminal.cols], bufferIndex);
+      }
+    });
+    it('surrogate char with combining', function(): void {
+      // eye of Ra with acute accent - string length of 3
+      const input = '𓂀\u0301 - the eye hiroglyph with an acute accent.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      // index 0..2 should map to 0
+      assert.deepEqual([0, 0], terminal.buffer.stringIndexToBufferIndex(0, 1));
+      assert.deepEqual([0, 0], terminal.buffer.stringIndexToBufferIndex(0, 2));
+      for (let i = 2; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i - 2)/terminal.cols) | 0, (i - 2) % terminal.cols], bufferIndex);
+      }
+    });
+    it('multiline surrogate with combining', function(): void {
+      const input = '𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301𓂀\u0301';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      // every buffer cell index contains 3 string indices 
+      for (let i = 0; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([(((i / 3) | 0) /terminal.cols) | 0, ((i / 3) | 0) % terminal.cols], bufferIndex);
+      }
+    });
+    it('fullwidth chars', function(): void {
+      const input = 'These １２３ are some fat numbers.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      for (let i = 0; i < 6; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([(i/terminal.cols) | 0, i % terminal.cols], bufferIndex);
+      }
+      // string index 6, 7, 8 take 2 cells
+      assert.deepEqual([0, 8], terminal.buffer.stringIndexToBufferIndex(0, 7));
+      assert.deepEqual([1, 0], terminal.buffer.stringIndexToBufferIndex(0, 8));
+      // rest of the string has offset of +3
+      for (let i = 9; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i + 3)/terminal.cols) | 0, (i + 3) % terminal.cols], bufferIndex);
+      }
+    });
+    it('multiline fullwidth chars', function(): void {
+      const input = '１２３４５６７８９０１２３４５６７８９０';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      for (let i = 9; i < input.length; ++i) {
+        const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, i);
+        assert.deepEqual([((i << 1)/terminal.cols) | 0, (i << 1) % terminal.cols], bufferIndex);
+      }
+    });
+    it('fullwidth combining with emoji - match emoji cell', function(): void {
+      const input = 'Lots of ￥\u0301 make me 😃.';
+      terminal.write(input);
+      const s = wholeString(terminal, terminal.buffer.getWrappedRangeForLine(0));
+      assert.equal(input, s);
+      const stringIndex = s.match(/😃/).index;
+      const bufferIndex = terminal.buffer.stringIndexToBufferIndex(0, stringIndex);
+      assert(terminal.buffer.lines.get(bufferIndex[0]).get(bufferIndex[1])[CHAR_DATA_CHAR_INDEX], '😃');
+    });
+  });
 });
diff --git a/src/Buffer.ts b/src/Buffer.ts
index 9487be4a..cb7d3b87 100644
--- a/src/Buffer.ts
+++ b/src/Buffer.ts
@@ -194,6 +194,26 @@ export class Buffer implements IBuffer {
     this.scrollBottom = newRows - 1;
   }
 
+  public stringIndexToBufferIndex(lineIndex: number, stringIndex: number): number[] {
+    if (!stringIndex) {
+      return [lineIndex, 0];
+    }
+    while (stringIndex) {
+      let line = this.lines.get(lineIndex);
+      if (!line) {
+        [-1, -1];
+      }
+      for (let i = 0; i < line.length; ++i) {
+        stringIndex -= line.get(i)[CHAR_DATA_CHAR_INDEX].length;
+        if (stringIndex < 0) {
+          return [lineIndex, i];
+        }
+      }
+      lineIndex++;
+    }
+    return [lineIndex, 0];
+  }
+
   /**
    * Translates a buffer line to a string, with optional start and end columns.
    * Wide characters will count as two columns in the resulting string. This
diff --git a/src/Types.ts b/src/Types.ts
index df3f1a79..820a8b89 100644
--- a/src/Types.ts
+++ b/src/Types.ts
@@ -282,6 +282,7 @@ export interface IBuffer {
   getWrappedRangeForLine(y: number): { first: number, last: number };
   nextStop(x?: number): number;
   prevStop(x?: number): number;
+  stringIndexToBufferIndex(lineIndex: number, stringIndex: number): number[];
 }
 
 export interface IBufferSet extends IEventEmitter {