diff --git a/hledger-lib/Hledger/Data/Journal.hs b/hledger-lib/Hledger/Data/Journal.hs
index 5f25f53f8..94d551bc0 100644
--- a/hledger-lib/Hledger/Data/Journal.hs
+++ b/hledger-lib/Hledger/Data/Journal.hs
@@ -585,7 +585,9 @@ checkBalanceAssertion _ _ = Right ()
 
 checkBalanceAssertionCommodity :: Posting -> Amount -> MixedAmount -> Either String ()
 checkBalanceAssertionCommodity p assertedamt actualbal
-  | isReallyZeroAmount diff = Right ()
+  -- this effectively compares the actual balance rounded to display precision (I believe),
+  -- with the asserted balance as written. See examples in balance assertions manual.
+  | isZeroAmount diff = Right ()
   | True              = Left err
     where
       assertedcomm = acommodity assertedamt
diff --git a/hledger-lib/hledger_journal.m4.md b/hledger-lib/hledger_journal.m4.md
index 7f63f0e65..93e6a4884 100644
--- a/hledger-lib/hledger_journal.m4.md
+++ b/hledger-lib/hledger_journal.m4.md
@@ -466,6 +466,34 @@ Balance assertions are checked against all postings, both real and
 [virtual](#virtual-postings). They are not affected by the `--real/-R`
 flag or `real:` query.
 
+### Assertions and precision
+
+The calculated account balance is rounded to display precision before checking.
+Eg: here the calculated balance is $1.006. The commodity directive causes
+users, and balance assertions, to see this rounded to two decimal places, ie $1.01,
+so this assertion passes:
+```journal
+commodity $1000.00
+
+2019/01/01
+    (a)             $0.006
+
+2019/01/02
+    (a)             $1.00  = $1.01
+```
+
+The asserted balance is not rounded to display precision. So this assertion fails:
+```journal
+commodity $1000.00
+
+2019/01/01
+    (a)             $0.006
+
+2019/01/02
+    (a)             $1.00  = $1.007
+# calculated: $1.01
+# asserted:   $1.007 (difference: +$0.001)
+```
 
 ## Balance Assignments
 
diff --git a/tests/journal/balance-assertions.test b/tests/journal/balance-assertions.test
index e247f668e..5b52d86a4 100755
--- a/tests/journal/balance-assertions.test
+++ b/tests/journal/balance-assertions.test
@@ -365,3 +365,35 @@ hledger -f- stats
 >>>
 >>>2 /unexpected '@'/
 >>>=1
+
+# 21. The calculated balance is rounded to display precision before checking.
+# Here the calculated balance is $1.005 but users, and balance assertions,
+# see it as $1.00 (because the commodity directive set display precision to 2).
+hledger -f- stats
+<<<
+commodity $1000.00
+
+2019/01/01
+    (a)             $0.006
+
+2019/01/02
+    (a)             $1.00  = $1.01
+
+>>> /Transactions/
+>>>2
+>>>=0
+
+# 22. The asserted balance is not rounded to display precision.
+hledger -f- stats
+<<<
+commodity $1000.00
+
+2019/01/01
+    (a)             $0.006
+
+2019/01/02
+    (a)             $1.00  = $1.007
+
+>>>
+>>>2 /difference: \+\$0\.001/
+>>>=1