Cone Temperature Converter and Glaze-Clay Cone Matcher

A kiln cone temperature chart tells you the temperature at which an Orton pyrometric cone bends. For example, a self-supporting cone 6 bends at 2232 °F (1222 °C) and cone 06 at 1828 °F (998 °C) when the kiln heats at 108 °F/hr. Use the converter below for any cone from 022 to 12, and check that your clay and glaze cones match.

How to use the cone temperature converter

• Pick the cone. Choose any cone from 022 (coolest) to 12 (hottest), including the half cones 05½ and 5½.
• Pick the cone type and heating rate. The rate is how fast your kiln climbs during the last 180 °F (100 °C) of the firing, usually the final segment of your program.
• Choose °F or °C. The result shows both units, with your chosen unit as the headline number.
• Optional: match clay and glaze. Enter the firing cone from your clay maker and your glaze maker. The tool reports Match when they are the same cone, or Mismatch and which one may be over- or under-fired.

The table under the result lists every published Orton value for that cone. If Orton does not publish a value for your combination, the tool says so. It never interpolates.

How cone temperatures work

A pyrometric cone measures heat work, which is temperature combined with time. A slower final climb gives the cone more time to soften, so it bends at a lower temperature; a faster climb pushes the bending point higher. That is why the Orton chart lists separate temperatures for each heating rate and cone type.

The converter is a direct lookup in the Orton chart. The °F and °C columns are related by °F = °C × 9/5 + 32, rounded to whole degrees. Three common self-supporting cones:

For cone 6, the gap between a slow and a fast final climb is 104 °F (58 °C), so picking the correct column matters more than memorizing one number.

Kiln cone temperature chart

All 204 published Orton combinations for cones 022 to 12, listed coolest to hottest. SSB = self-supporting cone; Large = large regular cone; Small = small regular cone, which the chart labels as fired in a gas kiln. Rates apply to the last 180 °F (100 °C) of firing. Source: Orton Ceramic Foundation, Pyrometric Cone Temperature Equivalents chart (PDF), values checked 2026-11-09.

Cite this page: “Cone Temperature Converter and Glaze-Clay Cone Matcher,” potteryhow.com, data checked 2026-11-09, Kiln cone temperature chart.

Reading a kiln cone temperature chart: cone types, rates and matching

Cone numbering. Cones with a leading zero sit at the cooler end of the scale, and among them a larger number is cooler, so 022 is cooler than 06. Without the leading zero, a larger number is hotter, so cone 1 is cooler than cone 10. The tool sorts cones by their true order on the chart, never by the label text.

Cone types. The chart covers self-supporting cones at three heating rates, large regular cones at two rates, and small cones at 540 °F/hr fired in a gas kiln. Cones 022, 021 and 020 appear only for self-supporting cones at the medium and fast rates and for small cones; cone 5½ appears only for self-supporting cones.

Matching clay and glaze. Clay and glaze labels usually state a firing cone or a range, such as cone 5–7. If your glaze is rated hotter than your clay, firing to the glaze cone may over-fire the clay, while firing to the clay cone may under-fire the glaze. The reverse applies when the glaze is rated cooler. When the cones differ, confirm against the clay and glaze manufacturers’ stated firing ranges and test-fire a sample first.

Methodology & sources

Every temperature comes from the Orton chart, re-keyed without rounding: 204 cone-and-rate combinations across 36 cones, checked 2026-11-09. Iron-free cones and other brands are left out. All °C values were cross-checked against the Orton columns on Wikipedia, and every °F value against °C × 9/5 + 32.

• Orton Ceramic Foundation – Pyrometric Cone Temperature Equivalents chart (PDF): all °F and °C values.
• Wikipedia – Pyrometric cone: cross-check of the °C values.
• potteryhow.com – Best Stoneware Clay and Best Porcelain Clay: examples of stated clay firing ranges.

Last updated: November 2026

FAQ

What temperature is cone 6?

On the Orton chart, a self-supporting cone 6 bends at 2232 °F (1222 °C) when the kiln heats at 108 °F/hr (60 °C/hr) over the last 180 °F (100 °C). At 27 °F/hr it is 2165 °F (1185 °C), and at 270 °F/hr it is 2269 °F (1243 °C).

Why does the same cone have several temperatures?

Cones measure heat work, which is temperature combined with time. A slower final heating rate lets the cone bend at a lower temperature, so Orton lists separate values for each heating rate and cone type.

What is the difference between cone 06 and cone 6?

The leading zero marks the cooler end of the scale: cone 06 is 1828 °F (998 °C) and cone 6 is 2232 °F (1222 °C) for self-supporting cones at 108 °F/hr. Cone numbers with a leading zero get cooler as the number gets larger.

Can I use a glaze rated for a different cone than my clay?

If the cones differ, one of them may be over- or under-fired. Confirm against the clay and glaze manufacturers’ stated firing ranges before you fire.

Why are some cone and rate combinations missing?

Orton publishes cones 022, 021 and 020 only for self-supporting cones at 108 and 270 °F/hr and small cones, and cone 5½ only for self-supporting cones. The tool shows only published values and never interpolates.

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