diff --git a/lib/estimators/TSR.js b/lib/estimators/TSR.js
index 88a0f39..465323f 100644
--- a/lib/estimators/TSR.js
+++ b/lib/estimators/TSR.js
@@ -57,7 +57,7 @@ module.exports = function (domain, range) {
   // Denominator i.e. determinant
   // It is zero iff domain[i] = domain[j] for every i and j in [0, n).
   // In other words, iff all the domain points are the same or there is only one domain point.
-  const det = N * a2 + N * b2 - a1 * a1 - b1 * b1
+  const det = N * a2 - a1 * a1 + N * b2 - b1 * b1
 
   if (Math.abs(det) < TOLERANCE) {
     // The domain points are the same.
diff --git a/test/estimators/TSR.test.js b/test/estimators/TSR.test.js
index 7e66f4a..7fd0335 100644
--- a/test/estimators/TSR.test.js
+++ b/test/estimators/TSR.test.js
@@ -96,4 +96,17 @@ module.exports = (ts) => {
 
     t.end()
   })
+
+  ts.test(title + 'avoids precision errors', (t) => {
+    const dom = [{ x: 314.24933946532116, y: 807.8879779776474 }]
+    const ran = [{ x: 314.24933946532116, y: 824.4274168968749 }]
+
+    t.transformsEqual(
+      estimateTSR(dom, ran),
+      { a: 1, b: 0, x: ran[0].x - dom[0].x, y: ran[0].y - dom[0].y },
+      'simple translation, no scaling or rotation'
+    )
+
+    t.end()
+  })
 }