Updated October 2026 · By the Peach State Pottery team
There is no single temperature for cone 6. That is the thing almost every cone chart online gets wrong by printing one number per cone.
A pyrometric cone is not a thermometer. It is a small clay cone formulated to soften and bend when it has absorbed a specific amount of heat work — temperature and time together. Fire slowly and the cone bends at a lower temperature, because it had longer to get there. Fire fast and it needs a higher temperature to do the same job. So the Orton Ceramic Foundation, which makes the cones, publishes three temperatures for every cone, one for each of three standard heating rates.
This page is the full table, 022 through 12, all three rates, with the medium-rate figure converted to Celsius. Bookmark it or print it for the studio wall.
Quick picks
The four numbers people come here for, all at Orton's standard 108°F/hr rate:
- Cone 06 — 1,828°F (998°C). The usual low-fire glaze and standard bisque cone.
- Cone 04 — 1,945°F (1,063°C). Earthenware glaze.
- Cone 6 — 2,232°F (1,222°C). Mid-fire stoneware and porcelain. The cone most studio potters live at.
- Cone 10 — 2,345°F (1,285°C). High-fire stoneware and reduction.
And the thing that catches people out: cone 06 and cone 6 are 404°F apart. Leading zeros count — 010 is cooler than 10 by nearly 700 degrees.
Orton self-supporting cone chart — cone 022 to cone 12
Temperatures are degrees Fahrenheit for Orton self-supporting cones, the triangular cones with the built-in foot that stand on a shelf without a holder. The three columns are the three heating rates Orton publishes, measured over the last 180°F of the firing — not the average rate for the whole firing. The Celsius column converts the 108°F/hr figure, which is the one to use if your controller is running a normal medium-speed program.
| Cone | 27°F/hr (slow) | 108°F/hr (medium) | 270°F/hr (fast) | 108°F/hr in °C | Typical use |
|---|---|---|---|---|---|
| 022 | 1087 | 1094 | 1166 | 590 | Overglaze enamels, china paint |
| 021 | 1112 | 1143 | 1189 | 617 | Overglaze enamels, china paint |
| 020 | 1159 | 1180 | 1231 | 638 | Overglaze enamels, china paint |
| 019 | 1213 | 1252 | 1283 | 678 | China paint, lustres |
| 018 | 1267 | 1319 | 1353 | 715 | China paint, decals |
| 017 | 1301 | 1360 | 1405 | 738 | Glass slumping range |
| 016 | 1368 | 1422 | 1465 | 772 | Glass slumping, tack fuse |
| 015 | 1382 | 1456 | 1504 | 791 | Glass tack fuse |
| 014 | 1395 | 1485 | 1540 | 807 | Glass full fuse range |
| 013 | 1485 | 1539 | 1582 | 838 | Glass full fuse, enamels |
| 012 | 1549 | 1582 | 1620 | 861 | Glass casting, decals |
| 011 | 1575 | 1607 | 1641 | 875 | Lustres, metal clay |
| 010 | 1636 | 1657 | 1679 | 903 | Metal clay, raku glaze |
| 09 | 1665 | 1688 | 1706 | 920 | Raku, low-fire glaze |
| 08 | 1692 | 1728 | 1753 | 942 | Low-fire glaze |
| 07 | 1764 | 1789 | 1809 | 976 | Low-fire glaze, bisque |
| 06 | 1798 | 1828 | 1855 | 998 | Low-fire glaze, standard bisque |
| 05½ | 1839 | 1859 | 1877 | 1015 | Low-fire glaze |
| 05 | 1870 | 1888 | 1911 | 1031 | Low-fire glaze, decals |
| 04 | 1915 | 1945 | 1971 | 1063 | Earthenware glaze |
| 03 | 1960 | 1987 | 2019 | 1086 | Earthenware, bisque |
| 02 | 1972 | 2016 | 2052 | 1102 | Earthenware, bisque |
| 01 | 1999 | 2046 | 2080 | 1119 | Upper bisque range |
| 1 | 2028 | 2079 | 2109 | 1137 | Low mid-range |
| 2 | 2034 | 2088 | 2127 | 1142 | Low mid-range |
| 3 | 2039 | 2106 | 2138 | 1152 | Low mid-range |
| 4 | 2086 | 2124 | 2161 | 1162 | Mid-range |
| 5 | 2118 | 2167 | 2205 | 1186 | Mid-range stoneware |
| 5½ | 2133 | 2197 | 2237 | 1203 | Mid-range stoneware |
| 6 | 2165 | 2232 | 2269 | 1222 | Mid-fire stoneware and porcelain |
| 7 | 2194 | 2262 | 2295 | 1239 | Upper mid-range |
| 8 | 2212 | 2280 | 2320 | 1249 | Low high-fire |
| 9 | 2235 | 2300 | 2336 | 1260 | High-fire |
| 10 | 2284 | 2345 | 2381 | 1285 | High-fire stoneware, reduction |
| 11 | 2322 | 2361 | 2399 | 1294 | High-fire, porcelain |
| 12 | 2345 | 2383 | 2419 | 1306 | High-fire, industrial |
Source: Orton Ceramic Foundation cone chart, self-supporting cones, Fahrenheit. The Celsius column is our conversion of the 108°F/hr figure, rounded to the nearest degree. Orton publishes these for electric kilns in an air atmosphere, and treats a cone as fired when its tip has bent down level with its base.
How to read the three columns
The three rates — 27, 108 and 270°F per hour — are not the speed of your whole firing. Orton defines them as the heating rate during the last 180°F of the firing. That is the stretch that does the final work on the cone, and it is the number your controller's last ramp segment is setting.
So if your cone 6 program's final segment climbs at 108°F/hr, read the middle column: 2,232°F. If you run a slow glaze ramp at 27°F/hr to the end, cone 6 is reached at 2,165°F — 67 degrees lower. And if your last segment is a full-speed climb at 270°F/hr, you will not reach cone 6 until 2,269°F.
Three practical consequences:
A fast cone 6 firing gets hotter than a slow cone 8 firing. Cone 6 at 270°F/hr is 2,269°F. Cone 8 at 27°F/hr is 2,212°F. If you have ever wondered why a kiln that "reached temperature" still turned out underfired glazes, this is the mechanism — temperature on the display is not the same as heat work in the clay.
Your controller's cone-fire mode already knows this. Orton-built controllers — the AutoFire and SENTINEL families fitted to most of the kilns we sell — have the table in firmware. Pick cone 6 and a speed, and the controller works out the cutoff temperature. That is why the same "cone 6" program ends at a slightly different display temperature on slow versus fast.
Witness cones still earn their place. A thermocouple drifts, and it reads one spot. A cone on each shelf tells you what the ware actually absorbed, including whether your top shelf is running hotter than your bottom one. Cones cost pennies. Elements and glaze loads do not.
Self-supporting, large, small and bar cones
The table above is for self-supporting cones, which is what most studios use and what Orton's headline chart covers. The other shapes exist, and they are not interchangeable:
| Cone type | What it is | Where it is used |
|---|---|---|
| Self-supporting | Triangular cone with a wide moulded foot; stands up on its own | Witness cones on the shelf. The default for studio firing, and the type our table covers. |
| Large (tall) cones | Same height, no foot; must be set in a wad of clay or a holder at an angle | Witness cones in a holder, and the sitter bar on some kiln-sitter kilns. |
| Small cones | Shorter cones, different formulation | Kiln sitters. Their equivalent temperatures differ from this chart — use Orton's small-cone figures. |
| Bar cones | Flat bars that sag rather than bend | Kiln sitters and some industrial controls. |
If you have a mechanical kiln sitter, the cone that shuts your kiln off is a small cone or a bar, not a self-supporting one, and its equivalent temperature is different. That is one of several reasons manufacturers have moved to digital control — Olympic, for instance, carries a shorter warranty on kiln-sitter models than on its digital ones.
What a kiln's "cone rating" means
A kiln rated cone 10 is not promising to deliver 2,345°F forever. The rating reflects wattage, element design, brick thickness and controller together, and it is a ceiling you should sit below, not at.
Here is the part worth knowing before you buy: the cone rating on a spec sheet usually comes with a rounded temperature next to it. "Cone 10 / 2350°F" is cone 10 at a normal heating rate, rounded up five degrees. "Cone 6 / 2250°F" is a rounding of 2,232°F. Those rounded figures are shorthand; the cone is the real spec.
And the practical rule most of the industry agrees on: buy more cone rating than you fire to. A kiln with power in reserve reaches temperature faster, spends less time soaking at high heat, and burns through elements more slowly than a kiln straining at its ceiling. We go through the arithmetic — including where cone 10 costs real money and where it is free — in Cone 6 vs Cone 10.
Rough guide to where our catalog sits:
- Cone 10 (2,345°F): most of the Olympic and Cress pottery lines, and Evenheat's High Fire series. Browse Cone 10 Kilns.
- Cone 8 (2,280°F): Evenheat's RM II series — two cones of headroom above a cone 6 firing, which is exactly the margin you want. See the Evenheat range.
- Cone 6 (2,232°F): most 120V test and jewelry kilns. See Best 120V Kilns and 120V kilns.
- Under cone 06 (1,828°F): glass kilns, annealers and most heat-treating ovens. These are not low-rated pottery kilns — they are built differently, with the elements in the lid instead of the walls. See Pottery Kiln vs Glass Kiln and kilns to 1800°F.
Cones for glass, metal clay and enamel
Glass workers rarely talk in cones, and they are right not to — glass is driven by precise temperatures and holds, not by heat work. But the low cone numbers do map onto the glass range, which helps if you are reading a mixed-media book or working out whether a kiln's rating will cover a fuse.
Full fuse territory, roughly 1,465–1,500°F, lands around cone 015 to 014. Slumping at 1,200–1,250°F is about cone 019 to 018. Annealing happens below every cone on the chart. If you are sizing a kiln for glass, use the temperature, not the cone — our glass fusing temperature guide has the schedules, and the annealing guide covers the cooldown.
FAQ
What temperature is cone 6?
2,232°F (1,222°C) at Orton's standard 108°F/hr heating rate for self-supporting cones. At 27°F/hr it is 2,165°F and at 270°F/hr it is 2,269°F. Manufacturers usually round it to 2,250°F on spec sheets.
What temperature is cone 10?
2,345°F (1,285°C) at 108°F/hr. The range across all three published rates is 2,284°F to 2,381°F. Spec sheets round it to 2,350°F.
What is the difference between cone 06 and cone 6?
404°F. Cone 06 is 1,828°F and cone 6 is 2,232°F, both at 108°F/hr. Cones with a leading zero run cooler as the number gets bigger — 022 is the coolest cone on the chart. Cones without a zero run hotter as the number gets bigger. Mixing them up is the most common and most expensive cone mistake there is.
Why does one cone have three temperatures?
Because a cone measures heat work — the combined effect of temperature and time — not temperature. Held longer at a lower temperature, the cone absorbs the same total heat and bends anyway. Orton publishes equivalents at 27, 108 and 270°F/hr, measured over the last 180°F of the firing, so you can pick the one that matches your final ramp.
What temperature is bisque firing?
Most studios bisque at cone 06 (1,828°F) or cone 04 (1,945°F). Cone 06 is the common default for commercial clay bodies, but check what your clay manufacturer specifies — bisque too low and the ware stays porous and takes glaze unevenly; bisque too high and the body closes up and will not take glaze properly at all.
Do I still need witness cones with a digital controller?
Yes. A digital controller reads one thermocouple in one place, and the reading drifts as the thermocouple ages. Witness cones on each shelf show you what the ware actually absorbed and reveal top-to-bottom unevenness, which is the thing a single thermocouple cannot tell you.
Are Celsius cone charts different?
No — same cones, same heat work, just converted. Orton publishes both. Our Celsius column converts the 108°F/hr Fahrenheit figures; small rounding differences against Orton's own Celsius chart are conversion artifacts, not disagreements.
Can I use this chart for small cones or bar cones?
No. These figures are for self-supporting cones. Small cones and bars have different formulations and different equivalent temperatures. If your kiln has a mechanical sitter, use Orton's small-cone or bar figures instead.
Still not sure? Ask us.
We are a Georgia kiln dealer, not a marketplace. Tell us what you fire, what cone your clay or glaze calls for and what is in your breaker panel, and we will tell you which kiln fits — including when the answer is the cheaper one.
- Expert help before you buy. Real answers on cone ratings, amps and clay bodies from people who sell all of these brands. Contact us or try the kiln finder.
- Flat-rate freight with liftgate. Kilns are heavy. Our freight is flat-rate and includes liftgate service. See shipping details.
- Price match guarantee. Find it cheaper from an authorized dealer and we will match it — see our price match guarantee.
Browse Ceramic Kilns, Cone 10 Kilns or Kiln Accessories.
More from The Kiln Room: Cone 6 vs Cone 10 · What Size Kiln Do I Need? · Kiln Electrical Requirements · Glass Fusing Temperature Guide
Cone equivalent temperatures are published by the Edward Orton Jr. Ceramic Foundation and apply to electric firing in an air atmosphere at the stated heating rate over the last 180°F of the firing. Always follow the cone your clay and glaze manufacturers specify.