diff --git a/src/ast.fs b/src/ast.fs
index 4aef9518..a3d46782 100644
--- a/src/ast.fs
+++ b/src/ast.fs
@@ -43,7 +43,7 @@ let stringToJumpKeyword = function
 
 type Expr =
     | Int of int * string
-    | Float of float * string
+    | Float of decimal * string
     | Var of Ident
     | Op of string
     | FunCall of Expr * Expr list
diff --git a/src/parse.fs b/src/parse.fs
index 686d3cf8..845b810a 100644
--- a/src/parse.fs
+++ b/src/parse.fs
@@ -54,7 +54,7 @@ module private ParseImpl =
         let conv s =
             let ok, res = System.Int32.TryParse(s : string)
             if ok then Ast.Int (res, "")
-            else Ast.Float (try float s, "" with _ -> failwith ("invalid number: " + s))
+            else Ast.Float (try decimal s, "" with _ -> failwith ("invalid number: " + s))
         regex r .>> ws |>> conv
 
     let anyNumber =
diff --git a/src/printer.fs b/src/printer.fs
index 7fe78ec1..c36df0c8 100644
--- a/src/printer.fs
+++ b/src/printer.fs
@@ -3,6 +3,7 @@
 open System
 open Ast
 open Options.Globals
+open System.Text.RegularExpressions
 
 module private PrinterImpl =
 
@@ -46,13 +47,17 @@ module private PrinterImpl =
         List.map toS li |> String.concat ","
 
     let floatToS f =
-        let si = if f < 0. then "-" else ""
-        let test = out "%g" (abs f)
-        // display "3." instead of "3"
-        if fst (System.Int32.TryParse test) then (out "%g." f)
-        // display ".5" instead of "0.5"
-        else if test.[0] = '0' then si + (test.[1..])
-        else si + test
+        let si = if f < 0.M then "-" else ""
+        let f = abs (float f)
+        let str = f.ToString("g", System.Globalization.CultureInfo.InvariantCulture)
+        let str = if str.EndsWith(".0") then str.[0..str.Length-2] else str
+
+        if Regex.Match(str, "^\\d+$").Success then
+            si + str + "." // display "3." instead of "3"
+        elif str.[0] = '0' && str.Length > 2 then
+            si + (str.[1..]) // display ".5" instead of "0.5"
+        else
+            si + str
 
     let rec exprToS exp = exprToSLevel 0 exp
 
diff --git a/src/rewriter.fs b/src/rewriter.fs
index 45cde208..14e70fa5 100644
--- a/src/rewriter.fs
+++ b/src/rewriter.fs
@@ -71,7 +71,7 @@ let rec private simplifyExpr env = function
     | FunCall(Op ",", [e1; FunCall(Op ",", [e2; e3])]) ->
         FunCall(Op ",", [simplifyExpr env (FunCall(Op ",", [e1; e2])); e3])
 
-    | FunCall(Op "-", [x; Float (f, s)]) when f < 0. ->
+    | FunCall(Op "-", [x; Float (f, s)]) when f < 0.M ->
         FunCall(Op "+", [x; Float (-f, s)]) |> simplifyExpr env
     | FunCall(Op "-", [x; Int (i, s)]) when i < 0 ->
         FunCall(Op "+", [x; Int (-i, s)]) |> simplifyExpr env
@@ -92,15 +92,15 @@ let rec private simplifyExpr env = function
     | FunCall(Op "!=", [Float (i1,_); Float (i2,_)]) -> bool(i1 <> i2)
 
     // Stupid simplifications (they can be useful to simplify rewritten code)
-    | FunCall(Op "/", [e; Float (1.,_)]) -> e
-    | FunCall(Op "*", [e; Float (1.,_)]) -> e
-    | FunCall(Op "*", [Float (1.,_); e]) -> e
-    | FunCall(Op "*", [_; Float (0.,_) as e]) -> e
-    | FunCall(Op "*", [Float (0.,_) as e; _]) -> e
-    | FunCall(Op "+", [e; Float (0.,_)]) -> e
-    | FunCall(Op "+", [Float (0.,_); e]) -> e
-    | FunCall(Op "-", [e; Float (0.,_)]) -> e
-    | FunCall(Op "-", [Float (0.,_); e]) -> FunCall(Op "-", [e])
+    | FunCall(Op "/", [e; Float (1.M,_)]) -> e
+    | FunCall(Op "*", [e; Float (1.M,_)]) -> e
+    | FunCall(Op "*", [Float (1.M,_); e]) -> e
+    | FunCall(Op "*", [_; Float (0.M,_) as e]) -> e
+    | FunCall(Op "*", [Float (0.M,_) as e; _]) -> e
+    | FunCall(Op "+", [e; Float (0.M,_)]) -> e
+    | FunCall(Op "+", [Float (0.M,_); e]) -> e
+    | FunCall(Op "-", [e; Float (0.M,_)]) -> e
+    | FunCall(Op "-", [Float (0.M,_); e]) -> FunCall(Op "-", [e])
 
     // No simplification when numbers have different suffixes
     | FunCall(_, [Int (_, su1); Int (_, su2)]) as e when su1 <> su2 -> e
@@ -112,7 +112,7 @@ let rec private simplifyExpr env = function
     | FunCall(Op "/", [Int (i1, su); Int (i2, _)]) -> Int (i1 / i2, su)
     | FunCall(Op "%", [Int (i1, su); Int (i2, _)]) -> Int (i1 % i2, su)
 
-    | FunCall(Op "-", [Float (0.0,su)]) -> Float (0.0, su)
+    | FunCall(Op "-", [Float (0.M,su)]) -> Float (0.M, su)
     | FunCall(Op "-", [Float (f1,su)]) -> Float (-f1, su)
     | FunCall(Op "-", [Float (i1,su); Float (i2,_)]) -> Float (i1 - i2, su)
     | FunCall(Op "+", [Float (i1,su); Float (i2,_)]) -> Float (i1 + i2, su)
@@ -123,12 +123,12 @@ let rec private simplifyExpr env = function
         else div
 
     // iq's smoothstep trick: http://www.pouet.net/topic.php?which=6751&page=1#c295695
-    | FunCall(Var var, [Float (0.,_); Float (1.,_); _]) as e when var.Name = "smoothstep" -> e
+    | FunCall(Var var, [Float (0.M,_); Float (1.M,_); _]) as e when var.Name = "smoothstep" -> e
     | FunCall(Var var, [a; b; x]) when var.Name = "smoothstep" && options.smoothstepTrick ->
         let sub1 = FunCall(Op "-", [x; a])
         let sub2 = FunCall(Op "-", [b; a])
         let div  = FunCall(Op "/", [sub1; sub2]) |> mapExpr env
-        FunCall(Var (Ident "smoothstep"),  [Float (0.,""); Float (1.,""); div])
+        FunCall(Var (Ident "smoothstep"),  [Float (0.M,""); Float (1.M,""); div])
 
     | Dot(e, field) when options.canonicalFieldNames <> "" -> Dot(e, renameField field)
 
@@ -138,9 +138,9 @@ let rec private simplifyExpr env = function
         | _ -> e
 
     // pi is acos(-1), pi/2 is acos(0)
-    | Float(f, _) when f = 3.141592653589793 -> FunCall(Var (Ident "acos"), [Float (-1., "")])
-    | Float(f, _) when f = 6.283185307179586 -> FunCall(Op "*", [Float (2., ""); FunCall(Var (Ident "acos"), [Float (-1., "")])])
-    | Float(f, _) when f = 1.5707963267948966 -> FunCall(Var (Ident "acos"), [Float (0., "")])
+    | Float(f, _) when float f = 3.141592653589793 -> FunCall(Var (Ident "acos"), [Float (-1.M, "")])
+    | Float(f, _) when float f = 6.283185307179586 -> FunCall(Op "*", [Float (2.M, ""); FunCall(Var (Ident "acos"), [Float (-1.M, "")])])
+    | Float(f, _) when float f = 1.5707963267948966 -> FunCall(Var (Ident "acos"), [Float (0.M, "")])
 
     | e -> e
 
diff --git a/tests/commands.txt b/tests/commands.txt
index 6a16213c..4e5b890b 100644
--- a/tests/commands.txt
+++ b/tests/commands.txt
@@ -13,6 +13,7 @@
 --no-renaming --format c-array -o tests/unit/operators.expected tests/unit/operators.frag
 --no-renaming --format c-array -o tests/unit/minus-zero.expected tests/unit/minus-zero.frag
 --no-renaming --format indented -o tests/unit/inline.expected tests/unit/inline.frag
+--no-renaming --format c-array -o tests/unit/float.frag.expected tests/unit/float.frag
 
 # Partial renaming tests
 
diff --git a/tests/real/disco.expected b/tests/real/disco.expected
index e3249492..11716985 100644
--- a/tests/real/disco.expected
+++ b/tests/real/disco.expected
@@ -3,4 +3,3 @@
  */
 
 var disco_frag = `uniform vec2 resolution;uniform float time;uniform sampler2D tex0,tex1,tex2,tex3;vec4 s(vec2 px,float z){float l=3.1415,k=time*sign(z),x=px.x*320.*.0065*z,y=px.y*240.*.006*z,c=sqrt(x*x+y*y);if(c>1.)return vec4(0.);else{float u=-.4*sign(z)+sin(k*.05),v=sqrt(1.-x*x-y*y),q=y*sin(u)-v*cos(u);y=y*cos(u)+v*sin(u);v=acos(y);u=acos(x/sin(v))/(2.*l)*120.*sign(q)-k;v=v*60./l;q=cos(floor(v/l));c=pow(abs(cos(u)*sin(v)),.2)*.1/(q+sin(float(int((u+l/2.)/l))+k*.6+cos(q*25.)))*pow(1.-c,.9);vec4 res;if(c<0.)res=vec4(-c/2.*abs(cos(k*.1)),0.,-c*2.*abs(sin(k*.04)),1.);else res=vec4(c,c*2.,c*2.,1.);return res;}}void main(){vec2 p=-1.+2.*gl_FragCoord.xy/resolution.xy;vec4 c=vec4(0.);for(int i=80;i>0;i--)c+=s(p,1.-float(i)/80.)*(.008-float(i)*5e-05);vec4 d=s(p,1.);gl_FragColor=(d.w==0.?s(p,-.2)*.02:d)+sqrt(c);}`
-
diff --git a/tests/real/kinder_painter.expected b/tests/real/kinder_painter.expected
index 30352bf1..0c518bc6 100644
--- a/tests/real/kinder_painter.expected
+++ b/tests/real/kinder_painter.expected
@@ -152,8 +152,8 @@
    "vec4 ref;"
    "vec2 p=-1.+2.*gl_FragCoord.xy/resolution.xy;"
    "p*=vec2(resolution.x/resolution.y,1.);"
-   "fpar00[0]=vec4(1.2*sin(2.07342*time),0.,1.8*sin(2.45041*time+1.),1);"
-   "fpar00[1]=vec4(1.5*sin(1.94776*time+4.),sin(1.8221*time+1.9),1.8*sin(1.8221*time),1);"
+   "fpar00[0]=vec4(1.2*sin(2.073423*time),0.,1.8*sin(2.450409*time+1.),1);"
+   "fpar00[1]=vec4(1.5*sin(1.947761*time+4.),sin(1.822099*time+1.9),1.8*sin(1.822099*time),1);"
    "fpar00[2]=vec4(-1.2,0.,0.,.4);"
    "fpar00[3]=vec4(1.2,0.,0.,.4);"
    "fpar00[4]=vec4(0.,1.,0.,2.);"
@@ -183,4 +183,3 @@
    "col=mix(col,col2,.5-.5*ref.w);"
    "gl_FragColor=col;"
  "}",
-
diff --git a/tests/real/leizex.expected b/tests/real/leizex.expected
index 9ae8b84a..21be98b4 100644
--- a/tests/real/leizex.expected
+++ b/tests/real/leizex.expected
@@ -17,7 +17,7 @@ _leizex_frag:
 	db   'f=f*f*(3.-2.*f);'
 	db   'int n=ip.x+ip.y*57+113*ip.z+sem;'
 	db   'float res=mix(mix(mix(coolfFunc3d2(n+0),coolfFunc3d2(n+1),f.x),mix(coolfFunc3d2(n+57),coolfFunc3d2(n+58),f.x),f.y),mix(mix(coolfFunc3d2(n+113),coolfFunc3d2(n+114),f.x),mix(coolfFunc3d2(n+170),coolfFunc3d2(n+171),f.x),f.y),f.z);'
-	db   'return 1.-res*9.31323e-10;'
+	db   'return 1.-res*(1./1073741824.);'
 	db '}'
 	db 'vec2 celular(in vec3 x)'
 	db '{'
@@ -29,7 +29,7 @@ _leizex_frag:
 	db       'for(int i=-1;i<=1;i++)'
 	db         '{'
 	db           'int nn=ip.x+i+57*(ip.y+j)+113*(ip.z+k);'
-	db           'vec3 di=vec3(float(i),float(j),float(k))-f+vec3(coolfFunc3d2(nn),coolfFunc3d2(nn+1217),coolfFunc3d2(nn+2513))/2.14748e+09;'
+	db           'vec3 di=vec3(float(i),float(j),float(k))-f+vec3(coolfFunc3d2(nn),coolfFunc3d2(nn+1217),coolfFunc3d2(nn+2513))/2147483647.;'
 	db           'float d2=dot(di,di);'
 	db           'if(d2<dmin.x)'
 	db             'dmin.y=dmin.x,dmin.x=d2;'
@@ -67,7 +67,7 @@ _leizex_frag:
 	db   'float r2=s.x*s.x*.32+s.y*s.y;'
 	db   'vec2 d=s*(7.-sqrt(37.5-11.5*r2))/(r2+1.);'
 	db   'vec3 rayTar=vec3(0.,1.5,2.);'
-	db   'rayPos=rayTar+vec3(-sin(6.28319*ftime/20.),.75*cos(6.28319*ftime/20.+.5),-cos(6.28319*ftime/20.));'
+	db   'rayPos=rayTar+vec3(-sin(6.2831853*ftime/20.),.75*cos(6.2831853*ftime/20.+.5),-cos(6.2831853*ftime/20.));'
 	db   'rayTar+=.075*vec3(noise3f(vec3(2.*ftime,0.,.5),0),noise3f(vec3(2.*ftime,.1,.4),7),noise3f(vec3(2.*ftime,.2,.3),9));'
 	db   'float roll=.1*noise3f(vec3(2.*ftime,0.,0.),13);'
 	db   'vec3 up=vec3(0.,cos(roll),sin(roll)),dd=normalize(rayTar-rayPos),rr=normalize(cross(dd,up)),uu=normalize(cross(rr,dd));'
@@ -105,4 +105,3 @@ _leizex_frag:
 	db   'col*=.5+.5*(1.-p.x)*(1.+p.x);'
 	db   'gl_FragColor=vec4(col,1.);'
 	db '}', 0
-
diff --git a/tests/real/lunaquatic.frag.expected b/tests/real/lunaquatic.frag.expected
index 77fc5d22..9f32cf94 100644
--- a/tests/real/lunaquatic.frag.expected
+++ b/tests/real/lunaquatic.frag.expected
@@ -34,7 +34,7 @@ const char *lunaquatic_frag =
  "{"
    "int x=int(v.x*40.+v.y*6400.);"
    "x=x<<13^x;"
-   "return 1.-float(x*(x*x*15731+789221)+1376312589&2147483647)/1.07374e+09;"
+   "return 1.-float(x*(x*x*15731+789221)+1376312589&2147483647)/1073741824.;"
  "}"
  "float p(float z)"
  "{"
diff --git a/tests/real/oscars_chair.frag.expected b/tests/real/oscars_chair.frag.expected
index 6f2c562b..a494fd64 100644
--- a/tests/real/oscars_chair.frag.expected
+++ b/tests/real/oscars_chair.frag.expected
@@ -88,7 +88,7 @@ const char *oscars_chair_frag =
  "void main()"
  "{"
    "if(gl_TexCoord[0].y==0)"
-     "gl_FragColor.xyz=vec3(gl_TexCoord[0].xx,fract(sin(float((int(gl_FragCoord.x)*19349663^int(gl_FragCoord.y)*83492791)%38069))*43758.5));"
+     "gl_FragColor.xyz=vec3(gl_TexCoord[0].xx,fract(sin(float((int(gl_FragCoord.x)*19349663^int(gl_FragCoord.y)*83492791)%38069))*43758.545));"
    "else"
      " if(gl_TexCoord[0].y==1)"
        "{"
diff --git a/tests/real/the_real_party_is_in_your_pocket.frag.expected b/tests/real/the_real_party_is_in_your_pocket.frag.expected
index 94f1637a..45292f38 100644
--- a/tests/real/the_real_party_is_in_your_pocket.frag.expected
+++ b/tests/real/the_real_party_is_in_your_pocket.frag.expected
@@ -241,7 +241,7 @@ const char *the_real_party_is_in_your_pocket_frag =
  "float y;"
  "float m()"
  "{"
-   "return fract(sin(y++)*43758.5);"
+   "return fract(sin(y++)*43758.5453123);"
  "}"
  "vec3 h(vec3 l,vec3 v)"
  "{"
diff --git a/tests/real/yx_long_way_from_home.frag.expected b/tests/real/yx_long_way_from_home.frag.expected
index f149851f..7eaeae58 100644
--- a/tests/real/yx_long_way_from_home.frag.expected
+++ b/tests/real/yx_long_way_from_home.frag.expected
@@ -30,7 +30,7 @@ const char *yx_long_way_from_home_frag =
  "}"
  "vec2 s(const float v)"
  "{"
-   "return fract(sin(vec2(v,v+1.))*vec2(43758.5));"
+   "return fract(sin(vec2(v,v+1.))*vec2(43758.5453123));"
  "}"
  "int f;"
  "vec3 e(vec3 v)"
@@ -48,7 +48,7 @@ const char *yx_long_way_from_home_frag =
  "}"
  "float m(vec3 m)"
  "{"
-   "float x=1e+09;"
+   "float x=1000000000.;"
    "x=min(x,length(m-vec3(0,5,0))-2.5);"
    "vec3 i=m;"
    "i.x=abs(i.x-1.1)-.2;"
@@ -192,7 +192,7 @@ const char *yx_long_way_from_home_frag =
  "void main()"
  "{"
    "vec2 v=gl_FragCoord.xy/iResolution.xy-.5;"
-   "float y=iTime+(v.x+iResolution.x*v.y)*1.51269;"
+   "float y=iTime+(v.x+iResolution.x*v.y)*1.51269341231;"
    "i=s(y);"
    "v+=(i-.5)/iResolution.xy;"
    "v.x*=iResolution.x/iResolution.y;"
diff --git a/tests/unit/float.frag b/tests/unit/float.frag
index ca2e7137..8bba8ecc 100644
--- a/tests/unit/float.frag
+++ b/tests/unit/float.frag
@@ -1,3 +1,9 @@
+void precision() {
+  float a = 0.00000012345;
+  float b = 1.234567891234;
+  float c = 1234567.891234;
+}
+
 void main()
 {
 float f1 = 1.5;
@@ -10,8 +16,5 @@ float f7 = 2E-9;
 float f8 = 2E+6;
 float f9 = 2e10;
 
-float n = 1. / (f1 + f2 + f3 + f4 + f5);
-float o = 1. / (f6 * f8 * f7 * f9);
-
-gl_FragColor=vec4(n,o,n,0.);
+gl_FragColor=vec4(0.);
 }
diff --git a/tests/unit/float.frag.expected b/tests/unit/float.frag.expected
index 745c7441..a00da982 100644
--- a/tests/unit/float.frag.expected
+++ b/tests/unit/float.frag.expected
@@ -1,14 +1,14 @@
 /* File generated with Shader Minifier 1.1.6
  * http://www.ctrl-alt-test.fr
  */
-#ifndef FLOAT_FRAG_EXPECTED_
-# define FLOAT_FRAG_EXPECTED_
 
-const char *float_frag =
+// tests/unit/float.frag
+"void precision()"
+ "{"
+   "float a=1.2345e-07,b=1.234567891234,c=1234567.891234;"
+ "}"
  "void main()"
  "{"
-   "float e=1.5,r=3e-07,o=.42,a=0.,l=0.,g=-.002,i=2e-09,v=2e+06,c=2e+10,d=1./(e+r+o+a+l),f=1./(g*v*i*c);"
-   "gl_FragColor=vec4(d,f,d,0.);"
- "}";
-
-#endif // FLOAT_FRAG_EXPECTED_
+   "float f1=1.5,f2=3e-07,f3=.42,f4=0.,f5=0.,f6=-.002,f7=2e-09,f8=2000000.,f9=20000000000.;"
+   "gl_FragColor=vec4(0.);"
+ "}",
diff --git a/tests/unit/operators.expected b/tests/unit/operators.expected
index 33d3ab18..115b82bc 100644
--- a/tests/unit/operators.expected
+++ b/tests/unit/operators.expected
@@ -7,9 +7,8 @@
  "void main()"
  "{"
    "int a=11,b=7,c=2;"
-   "float f=2.62146;"
+   "float f=2.621464704;"
    "f=.7;"
    "f=1.4/3.;"
    "float g=mod(8.,3.);"
  "}",
-