Sugar Stage Temperature Calculator
Candy and caramel recipes give sugar stage temperatures (thread, soft ball, hard crack, caramel) at sea level, but water boils cooler at altitude, so your thermometer reads lower for the same syrup concentration. This calculator applies the published candy-making rule of subtracting 1 degree Fahrenheit per 500 feet of elevation to your sea-level target, then shows the adjusted stage temperature in both Fahrenheit and Celsius. Enter your stage target and your elevation. Use the cold-water test as a cross-check, since it does not depend on altitude.
Sugar stage altitude formula
temperature drop F = elevation feet / 500
adjusted target F = sea-level target F - temperature drop F
Celsius = (Fahrenheit - 32) * 5 / 9
The rule lowers the target by 1 degree Fahrenheit for each 500 feet of elevation. The Fahrenheit-to-Celsius conversion is the standard exact formula. Always confirm the stage with the traditional cold-water test.
Common sea-level sugar stages (degrees F)
- Thread: 230 to 235.
- Soft ball: 235 to 240; firm ball: 245 to 250.
- Hard ball: 250 to 265.
- Soft crack: 270 to 290; hard crack: 300 to 310.
- Caramel: about 320 to 350.
Sugar stages: frequently asked questions
Why adjust sugar stage temperatures for altitude?
Sugar syrup concentrates as water boils off, and the boiling temperature rises with sugar concentration. At altitude, water boils at a lower temperature, so a syrup reaches the same concentration at a lower thermometer reading. USDA and university extension guidance is to lower the target temperature as elevation increases so you do not overcook the syrup.
What is the altitude adjustment rule?
A widely published candy-making rule is to subtract about 1 degree Fahrenheit from the target temperature for every 500 feet of elevation above sea level. This calculator applies that rule: adjusted target equals the sea-level target minus elevation divided by 500. Verify the cold-water test as a cross-check.
What are the common sugar stages?
At sea level the classic Fahrenheit ranges are: thread 230 to 235, soft ball 235 to 240, firm ball 245 to 250, hard ball 250 to 265, soft crack 270 to 290, hard crack 300 to 310, and caramel about 320 to 350. Enter the sea-level target for your stage and the calculator adjusts it.
How do I convert the temperature to Celsius?
Celsius equals Fahrenheit minus 32, times 5, divided by 9. This calculator shows the adjusted target in both Fahrenheit and Celsius so you can use either thermometer scale.
Should I still use the cold-water test?
Yes. The cold-water test (dropping a little syrup into cold water and judging the ball or crack) is the traditional cross-check and does not depend on altitude or a calibrated thermometer. Use the adjusted temperature as a guide and confirm the stage with the cold-water test.
Official sources
- Colorado State University Extension: High Altitude Food Preparation.
- NIST: Temperature Conversion.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.