Pottery Cone Chart: Temperatures From Cone 022 to Cone 10
Potters talk about firing in cones, not degrees. "Fire it to cone 6" sounds like jargon until you see why: a cone measures how much heat your pots actually received, not just what a dial said.
This chart gives you the numbers, then explains how to use them.
The cone chart
These are approximate end-point temperatures for self-supporting Orton cones heated at about 60°C (108°F) per hour. Your kiln, your firing speed and the cone brand all move these numbers a little, so treat them as a guide and check your cone maker's own chart.
| Cone | Range | Approx. °C | Approx. °F | Typical use |
|---|---|---|---|---|
| 022 | Low fire | 586 | 1087 | Lusters and decals |
| 018 | Low fire | 717 | 1323 | Overglaze and some raku |
| 06 | Low fire | 999 | 1830 | Bisque, earthenware glazes |
| 04 | Low fire | 1060 | 1940 | Bisque, earthenware glazes |
| 5 | Mid fire | 1177 | 2151 | Stoneware, popular studio glazes |
| 6 | Mid fire | 1222 | 2232 | The most common studio glaze firing |
| 10 | High fire | 1285 | 2345 | Traditional stoneware and porcelain, often in reduction |
What low, mid and high fire mean
Low fire (roughly cone 022 to 04) is where earthenware lives. Clay stays more porous and colors are bright. It is also where most bisque firings land.
Mid fire (cone 4 to 7) is the studio workhorse. Cone 5 and 6 stoneware is strong, widely available and works in ordinary electric kilns, which is why so many community studios fire there.
High fire (cone 8 and up) is classic stoneware and porcelain territory. It needs kilns and elements built for the heat and is often paired with gas or wood firing and reduction.
Why cones instead of degrees
Heat is not just temperature. It is temperature over time. A slow climb to 1200°C does more work on clay and glaze than a fast one. Cones are made to soften and bend according to that combined effect, called heatwork, so they tell you what your pots experienced.
That is why studios put witness cones in the kiln where they can see them, even when the kiln has a controller. A controller reports what a thermocouple felt. A cone shows what the ware got.
How to match clay and glaze to a cone
Every clay body and glaze has a cone it is designed to mature at. Two rules keep you out of trouble:
- Match the clay to the firing. A cone 6 stoneware fired only to cone 06 stays soft and porous. Fired far above its range, it can slump or bloat.
- Match the glaze to the clay. A cone 06 glaze taken to cone 6 can run off the pot and glue it to the shelf. A cone 6 glaze taken to cone 06 stays dry and rough.
Always read the label on the clay bag and the glaze jar, and write the cone down in your records.
A typical two-firing path
Most pottery is fired twice:
- Bisque to cone 06 or 04. The clay becomes hard enough to handle and absorbs glaze.
- Glaze firing to the cone for your clay and glaze, such as cone 6.
The bisque is usually fired lower than the glaze firing so the pot stays porous enough to take glaze. Our guide to bisque vs glaze firing goes through the full reasoning.
Reading cones in the kiln
Cones are usually used in a pack of three: one cone below your target, the target itself, and one above. As the kiln heats, the first bends over, then your target, and the third stays standing.
- Target cone bent to about 3 o'clock: the right amount of heat.
- Guide cone down, target upright: under-fired.
- All three bent: over-fired.
Keep a record of every firing
Write down the cone, the schedule, the clay and the glaze for each load. When a glaze looks great, you will want to repeat it. When it runs, you will want to know why. A Claybook project log keeps the firing details with the pot so you can search them later.
If you are new to how clay changes in the kiln, start with our guide to clay bodies and test any new glaze on a tile first with glaze test tiles.