diff --git a/grammar.go b/grammar.go
index 3465375..0ee8893 100644
--- a/grammar.go
+++ b/grammar.go
@@ -35,6 +35,9 @@ func MergeGrammarData(lang string, data *GrammarData) {
 	maps.Copy(existing.Verbs, data.Verbs)
 	maps.Copy(existing.Nouns, data.Nouns)
 	maps.Copy(existing.Words, data.Words)
+	if data.Number != (NumberFormat{}) {
+		existing.Number = data.Number
+	}
 }
 
 // IrregularVerbs returns a copy of the irregular verb forms map.
diff --git a/loader.go b/loader.go
index 41c02df..31f98e4 100644
--- a/loader.go
+++ b/loader.go
@@ -222,6 +222,20 @@ func flattenWithGrammar(prefix string, data map[string]any, out map[string]Messa
 				continue
 			}
 
+			// Number formatting rules
+			if grammar != nil && fullKey == "gram.number" {
+				if thousands, ok := v["thousands"].(string); ok {
+					grammar.Number.ThousandsSep = thousands
+				}
+				if decimal, ok := v["decimal"].(string); ok {
+					grammar.Number.DecimalSep = decimal
+				}
+				if percent, ok := v["percent"].(string); ok {
+					grammar.Number.PercentFmt = percent
+				}
+				continue
+			}
+
 			// CLDR plural object
 			if isPluralObject(v) {
 				msg := Message{}
diff --git a/loader_test.go b/loader_test.go
index 2605f8a..1ce7f06 100644
--- a/loader_test.go
+++ b/loader_test.go
@@ -85,6 +85,17 @@ func TestFSLoaderLoad(t *testing.T) {
 		t.Errorf("punct.progress = %q, want '...'", grammar.Punct.ProgressSuffix)
 	}
 
+	// Number formatting from gram.number
+	if grammar.Number.ThousandsSep != "," {
+		t.Errorf("number.thousands = %q, want ','", grammar.Number.ThousandsSep)
+	}
+	if grammar.Number.DecimalSep != "." {
+		t.Errorf("number.decimal = %q, want '.'", grammar.Number.DecimalSep)
+	}
+	if grammar.Number.PercentFmt != "%s%%" {
+		t.Errorf("number.percent = %q, want '%%s%%%%'", grammar.Number.PercentFmt)
+	}
+
 	// Words from gram.word.*
 	if len(grammar.Words) == 0 {
 		t.Error("grammar has 0 words")
@@ -135,6 +146,11 @@ func TestFlattenWithGrammar(t *testing.T) {
 				"label":    ":",
 				"progress": "...",
 			},
+			"number": map[string]any{
+				"thousands": ",",
+				"decimal":   ".",
+				"percent":   "%s%%",
+			},
 			"article": map[string]any{
 				"indefinite": map[string]any{
 					"default": "a",
@@ -179,6 +195,11 @@ func TestFlattenWithGrammar(t *testing.T) {
 		t.Errorf("punct.label = %q, want ':'", grammar.Punct.LabelSuffix)
 	}
 
+	// Number formatting extracted
+	if grammar.Number.ThousandsSep != "," {
+		t.Errorf("number.thousands = %q, want ','", grammar.Number.ThousandsSep)
+	}
+
 	// Articles extracted
 	if grammar.Articles.IndefiniteDefault != "a" {
 		t.Errorf("article.indefinite.default = %q, want 'a'", grammar.Articles.IndefiniteDefault)
@@ -188,6 +209,9 @@ func TestFlattenWithGrammar(t *testing.T) {
 	if msg, ok := messages["prompt.yes"]; !ok || msg.Text != "y" {
 		t.Errorf("prompt.yes not flattened correctly, got %+v", messages["prompt.yes"])
 	}
+	if _, ok := messages["gram.number.thousands"]; ok {
+		t.Error("gram.number.thousands should not be flattened into messages")
+	}
 }
 
 func TestFlattenPluralObject(t *testing.T) {
diff --git a/numbers.go b/numbers.go
index b84a4ea..ecc4ece 100644
--- a/numbers.go
+++ b/numbers.go
@@ -9,15 +9,27 @@ import (
 
 func getNumberFormat() NumberFormat {
 	lang := currentLangForGrammar()
-	if idx := indexAny(lang, "-_"); idx > 0 {
-		lang = lang[:idx]
-	}
-	if fmt, ok := numberFormats[lang]; ok {
+	if fmt, ok := getLocaleNumberFormat(lang); ok {
 		return fmt
 	}
+	if idx := indexAny(lang, "-_"); idx > 0 {
+		if fmt, ok := getLocaleNumberFormat(lang[:idx]); ok {
+			return fmt
+		}
+	}
 	return numberFormats["en"]
 }
 
+func getLocaleNumberFormat(lang string) (NumberFormat, bool) {
+	if data := GetGrammarData(lang); data != nil && data.Number != (NumberFormat{}) {
+		return data.Number, true
+	}
+	if fmt, ok := numberFormats[lang]; ok {
+		return fmt, true
+	}
+	return NumberFormat{}, false
+}
+
 // FormatNumber formats an integer with locale-specific thousands separators.
 func FormatNumber(n int64) string {
 	return formatIntWithSep(n, getNumberFormat().ThousandsSep)
diff --git a/numbers_test.go b/numbers_test.go
index e86f86a..235b5b0 100644
--- a/numbers_test.go
+++ b/numbers_test.go
@@ -143,3 +143,25 @@ func TestFormatOrdinal(t *testing.T) {
 		}
 	}
 }
+
+func TestFormatNumberFromLocale(t *testing.T) {
+	svc, err := New()
+	if err != nil {
+		t.Fatalf("New() failed: %v", err)
+	}
+	SetDefault(svc)
+
+	if err := SetLanguage("fr"); err != nil {
+		t.Fatalf("SetLanguage(fr) failed: %v", err)
+	}
+
+	if got := FormatNumber(1234567); got != "1 234 567" {
+		t.Errorf("FormatNumber(fr) = %q, want %q", got, "1 234 567")
+	}
+	if got := FormatDecimal(1234.56); got != "1 234,56" {
+		t.Errorf("FormatDecimal(fr) = %q, want %q", got, "1 234,56")
+	}
+	if got := FormatPercent(0.85); got != "85 %" {
+		t.Errorf("FormatPercent(fr) = %q, want %q", got, "85 %")
+	}
+}
diff --git a/types.go b/types.go
index 13abb4b..dbe1c66 100644
--- a/types.go
+++ b/types.go
@@ -52,7 +52,7 @@ type TextDirection int
 
 const (
 	DirLTR TextDirection = iota // Left-to-right
-	DirRTL                     // Right-to-left
+	DirRTL                      // Right-to-left
 )
 
 // PluralCategory represents CLDR plural categories.
@@ -193,6 +193,7 @@ type GrammarData struct {
 	Words    map[string]string    // base word translations
 	Punct    PunctuationRules     // language-specific punctuation
 	Signals  SignalData           // disambiguation signal word lists
+	Number   NumberFormat         // locale-specific number formatting
 }
 
 // VerbForms holds verb conjugations.
@@ -385,7 +386,7 @@ var irregularVerbs = map[string]VerbForms{
 	"rebel": {Past: "rebelled", Gerund: "rebelling"}, "excel": {Past: "excelled", Gerund: "excelling"},
 	"cancel": {Past: "cancelled", Gerund: "cancelling"}, "travel": {Past: "travelled", Gerund: "travelling"},
 	"label": {Past: "labelled", Gerund: "labelling"}, "model": {Past: "modelled", Gerund: "modelling"},
-	"level": {Past: "levelled", Gerund: "levelling"},
+	"level":       {Past: "levelled", Gerund: "levelling"},
 	"format":      {Past: "formatted", Gerund: "formatting"},
 	"analyse":     {Past: "analysed", Gerund: "analysing"},
 	"organise":    {Past: "organised", Gerund: "organising"},