Django DecimalField generating "quantize result has too many digits for current context" error on save
decimal, django, django-models, python
Solution
The problem is that all the right-of-the-decimal `decimal_places` are consumed by every instance, regardless of whether you have non-zero digits there, leaving only `(max_digits - decimal_places)` digits for left-of-the-decimal.
So for `DecimalField(max_digits=2,decimal_places=2)`, there's room for zero digits to the left of the decimal, and "1.5" won't fit. And for `DecimalField(max_digits=11,decimal_places=8)`, there's room for only three digits to the left of the decimal, and "1005.7" won't fit.
Expand your `max_digits` and the values will work.
Problem
I've got a model like: ``` class ModelWithDecimal(models.Model): value = models.DecimalField(max_digits=2,decimal_places=2) ``` ...yet when I try... ``` obj = ModelWithDecimal(value="1.5") obj.save() ``` I get a `quantize result has too many digits for current context` error during the save. Shouldn't that be OK - it's less than 2 digits, and less than 2 digits after the decimal-point? The same error happens with a model: ``` class ModelWithDecimal(models.Model): value = models.DecimalField(max_digits=11,decimal_places=8) ``` ...and attempted instance... ``` obj = ModelWithDecimal(value="1005.7") obj.save() ``` Again, seems it should work: only 4 total digits (less than 11), and only 1 after decimal (less than 8). What's wrong?