Kiln Firing Schedule Calculator
Calculate kiln firing times and ramp rates for bisque and glaze firings.
Covers cone temperatures from 06 to 10 for electric and gas kilns.
Firing Schedule
How kiln firing schedules work:
Ceramics are fired in stages — each stage has a target ramp rate (degrees per hour) and a peak temperature determined by the cone number. Firing too fast causes cracking (thermal shock). Firing too slow wastes energy and time.
Two main firing types:
- Bisque firing (first firing of raw clay): Slow ramp to drive out all moisture and chemically-bound water. Typical peak: cone 06 (1,828°F / 998°C).
- Glaze firing (second firing with glaze applied): Faster initial ramp since the clay is already vitrified, but controlled at the top to mature the glaze evenly.
Common cone temperatures:
| Cone | °F | °C | Use |
|---|---|---|---|
| 06 | 1,828 | 998 | Standard bisque |
| 04 | 1,945 | 1,063 | Low-fire glaze |
| 6 | 2,232 | 1,222 | Mid-fire stoneware |
| 10 | 2,345 | 1,285 | High-fire stoneware/porcelain |
Standard bisque firing schedule (cone 06, electric kiln):
- Room temp → 250°F at 100°F/hr (water smoking phase — drives out moisture)
- 250°F → 1,000°F at 200°F/hr (organic burnout phase)
- 1,000°F → 1,828°F at 300°F/hr (quartz inversion at 1,063°F — go steady)
- Hold at peak for 10–15 minutes
- Cool naturally — do not open kiln until below 200°F
Total bisque time: approximately 10–12 hours firing + 12–24 hours cooling.
Glaze firing schedule (cone 6, electric kiln):
- Room temp → 250°F at 150°F/hr
- 250°F → 2,000°F at 300°F/hr
- 2,000°F → 2,232°F at 150°F/hr (controlled top end for even glaze melt)
- Hold at peak for 10 minutes
- Cool naturally
Tips:
- Load bisque loosely — pieces can touch but need airflow
- Glaze-fired pieces must NOT touch each other — glazes fuse surfaces together
- The quartz inversion point (~1,063°F) is dangerous both heating and cooling — ramp steadily through it