Why altitude changes baking
Air pressure falls by roughly half a pound per 1,000 feet — 14.7 psi at sea level, 12.3 at 5,000 ft, 10.2 at 10,000 ft. Two consequences drive every adjustment on this page: liquids evaporate faster and boil at lower temperatures, and leavening gases expand more quickly. A cake that rises beautifully at sea level over-expands at 7,000 feet, stretching its cell structure until it either sets coarse or collapses outright.
So the fixes all pull in the same direction: slightly less leavening so the rise is gentler, less sugar (which weakens cell walls) and more liquid to replace what evaporates, and a hotter oven to set the structure before the gas can over-inflate it.
The published adjustment table
These are Colorado State University Extension's figures, transcribed exactly — including the band boundaries, which are 3,500–6,500 / 6,500–8,500 / 8,500–10,000 ft. Many recipe sites reprint a 3,000/5,000/7,000 version that doesn't match the publication.
| Adjustment | 3,500–6,500 ft | 6,500–8,500 ft | 8,500–10,000 ft |
|---|---|---|---|
| Reduce baking powder, per tsp | ⅛ tsp | ⅛–¼ tsp | ¼ tsp |
| Reduce sugar, per cup | 0–1 Tbsp | 0–2 Tbsp | 1–3 Tbsp |
| Increase liquid, per cup | 1–2 Tbsp | 2–4 Tbsp | 3–4 Tbsp |
| Oven temperature | +15–25°F | +15–25°F | +15–25°F |
Source: CSU Extension, High Altitude Food Preparation (Table 3) . Below 3,000 ft the guide states no modification is needed; the table stops at 10,000 ft, and this calculator says so rather than extrapolating past it.
Boiling point by elevation
Anything simmered, boiled or candied is governed by this rather than the cake table — at altitude water boils cooler, so boiled foods cook more slowly.
| Altitude | Water boils at |
|---|---|
| Sea level | 212°F |
| 2,000 ft | 208°F |
| 5,000 ft | 203°F |
| 7,500 ft | 198°F |
| 10,000 ft | 193°F |
Common elevations
| City | Elevation | Water boils at |
|---|---|---|
| Denver, CO | 5,280 ft | ≈202°F |
| Albuquerque, NM | 5,312 ft | ≈202°F |
| Salt Lake City, UT | 4,226 ft | ≈204°F |
| Boise, ID | 2,704 ft | ≈207°F |
| Santa Fe, NM | 7,199 ft | ≈199°F |
| Laramie, WY | 7,220 ft | ≈199°F |
| Leadville, CO | 10,152 ft | ≈193°F |
| Mexico City, MX | 7,350 ft | ≈198°F |
Beyond cakes
- Yeast breads. Altitude's biggest effect is on rise time — dough doubles faster, and a rushed rise costs flavour. Use less yeast or punch down twice, and judge by the dough's size, not the clock. Flours are drier at altitude and take more liquid. Scaling the formula at the same time? The baker's percentage calculator keeps the ratios straight.
- Cookies. Often fine as written. If they spread, CSU suggests a slightly hotter oven, slightly less baking powder or soda, slightly less fat and sugar, and a little more liquid and flour.
- Deep frying. Lower the oil about 3°F per 1,000 feet — that's 15°F cooler at 5,000 ft — so the outside doesn't brown before the inside cooks.
- Candy and jellies. Cook to a finish temperature about 2°F lower per 1,000 feet, or use the reliable method: boil water, note its temperature, and cook jellies to 8°F above it.
- Pie crusts are largely unaffected — slightly more liquid may improve the texture, and that's all.
The advice worth repeating
CSU's own first instruction is the one most high-altitude pages skip: don't assume your sea-level recipe will fail. Try it as written first — it may need little or no modification. When it does need help, start with the smaller adjustment in the range; that's often all it takes, and it's far easier to add a second change than to unpick two at once. Repeated experiments with a specific recipe will beat any general table, including this one.