Pyrometric Cones and Kiln Temperature Ranges
To vitrify clay – to change it from clay to stone – it must be heated to a glowing state called incandescence. Many kiln users
today rely on their electronic and digital kiln controls, but long before the advent of those conveniences potters learned to
measure the temperature inside the kiln by placing small numbered cones in the kiln before firing. Each numbered cone
deforms at its own specific temperature, and so the temperature inside the kiln can be determined by seeing which cones
deform and when by looking into the inferno through a 1" peep hole like the one in the photo! Although fewer and fewer
potters use cones today, the cone number terminology is a popular and convenient shorthand for describing kiln
temperatures.
Temperatures shown below encompass only the range commonly used for the substances mentioned in the chart. In fact,
cone numbers do continue all the way to 42, an Orton cone that deforms at 3600°F.
Cone
#
Temp
°F
Temp
°C
Incandescence
Range
14
2525
1390
Brilliant White
High-Fire
13
2460
1350
Brilliant White
High-Fire
12
2375
1310
White
High-Fire
11
2340
1285
White
High-Fire
10
2300
1260
White
9
2280
1250
White
8
2240
1225
White
High-Fire S
t
High-Fire o
n
High-Fire e
7
2210
1210
Yellow-White
Mid-Fire
6
2175
1190
Yellow-White
Mid-Fire
5
2160
1180
Yellow-White
Mid-Fire
4
2130
1165
Yellow
Mid-Fire
3
2095
1145
Yellow
Lower
Mid-Fire
2
2080
1135
Yellow
Lower
Mid-Fire
1
2060
1125
Yellow
Lower
Mid-Fire
There is no "0" (zero) cone.
Substance Details
P
o
r
c
e
l
a
i
n
End Porcelain
Porcelain
Porcelain
Porcelain,
End High-Fire Stoneware
High-Fire Stoneware,
Begin Porcelain (definition)
High-Fire Stoneware
Begin High-Fire Stoneware
End Mid-Fire Stoneware
w
a
r
e
Mid-Fire Stoneware
Mid-Fire Stoneware
End Earthenware
E
a
r
t
h
e
n
Earthenware
Begin Mid-Fire Stoneware
Earthenware
(definition)
Earthenware
The "0" prefixes on the cone numbers below are like a minus sign.
01
2030
1110
Yellow
Lower
Mid-Fire
02
2000
1095
Yellow-Orange
Low-Fire
03
1980
1080
Yellow-Orange
Low-Fire
w
a
r
e
Earthenware
Earthenware
Glass begins to form within the clay
Earthenware
Earthenware,
End Bisque Firing
04
1920
1050
Yellow-Orange
Low-Fire
05
1880
1030
Orange
Low-Fire
06
1840
1005
Orange
Low-Fire
07
1785
975
Orange
Low-Fire
08
1735
945
Red-Orange
Low-Fire
09
1705
930
Red-Orange
Low-Fire
010
1635
890
Red-Orange
011
1605
875
Red-Orange
012
1545
840
Red-Orange
Low-Fire W
a
Low-Fire r
m
Low-Fire
B
i
s
q
u
e
Earthenware
Bisque Firing
Bisque Firing
Begin Earthenware
(definition)
Bisque Firing
Begin Bisque Firing
End Warm Glass
Warm Glass
Warm Glass
End Fuming
G
l
a
s
s
Warm Glass
FumingEnd Carbon, Burn Out
013
1485
805
Cherry Red
Very
Low-Fire
014
1395
760
Cherry Red
Very
Low-Fire
015
1380
750
Cherry Red
Very
Low-Fire
Carbon Burn Out, Fuming
016
1370
740
Dull Red
Very
Low-Fire
End Overglaze
Carbon Burn Out, Fuming
017
1330
705
Dull Red
Very
Low-Fire
Overglaze, Fuming, Carbon Burn Out
End Water Smoking
018
1260
680
Dull Red
Very
Low-Fire
019
1225
660
Dull Red
Very
Low-Fire
020
1159
625
Dull Dark Red
Very
Low-Fire
021
1110
600
Dull Dark Red
Very
Low-Fire
022
1085°
F
590°
C
Dull Dark Red
Very
Low-Fire
Cone 022 marks the lowest kiln temperature at which
incandescence of the ceramics is visible.
Begin Warm Glass (Slumping & Fusing)
Carbon Burn Out, Fuming
O
v
e
r
g
l
a
z
e
Overglaze
Fuming, Carbon Burn Out & Water Smoking
Overglaze
Fuming, Carbon Burn Out & Water Smoking
Overglaze
Fuming, Carbon Burn Out & Water Smoking
Overglaze
Fuming, Carbon Burn Out & Water Smoking
Begin Overglaze (China Paints, Decals)
Fuming, Carbon Burn Out & Water Smoking**
are already in progress at this temperature
** The early stage stage of bisque-firing or
single-firing, below 1200°F, when carbonates,
nitrates, sulfates, organic contaminants, and
chemically combined water volatize and outgas.