City comparison
Boulder, CO is about 20 miles (30 km) from Thornton, CO in a straight line. By road, the drive is roughly 20 miles, or about 22 min behind the wheel at highway speeds.
Driving distance is a rough estimate (great-circle × 1.25); driving time assumes a 60 mph blended average. Real trips run 10–20% longer with stops.
A direct flight from Boulder, CO to Thornton, CO takes about 2 min, covering roughly 20 miles in a straight line. Connecting itineraries with a layover typically add 1–3 hours.
Block-to-block estimate at ~500 mph cruise, including taxi, climb, and descent — what an airline would publish, not pure airborne time.
Thornton has a population of 141,799, vs 106,598 in Boulder — about 1.3× larger by population. By land area, Thornton covers about 37 sq mi vs 27 sq mi for Boulder.
Population from US Census ACS. Land area from the Census Gazetteer (city proper, excluding inland water).
Cost indices by category, with the US city average (100) marked.
Index: 100 = US city average. Lower is more affordable.
Side-by-side costs, salaries, and sub-category indices.
| Metric | Boulder | Thornton | Difference |
|---|---|---|---|
| Median rent | $1,853/mo | $1,758/mo | 5.4% higher in Boulder |
| Median home value | $919,700 | $445,200 | 106.6% higher in Boulder |
| Median household income | $80,243 | $95,064 | 18.5% higher in Thornton |
| Groceries index | 96.8 | 101.2 | 4.6% higher in Thornton |
| Utilities index | 86.5 | 91.2 | 5.4% higher in Thornton |
| Transportation index | 100.3 | 99.9 | ≈ equal (Boulder slightly higher) |
| Healthcare index | 100.2 | 99.9 | ≈ equal (Boulder slightly higher) |
How much you'd need to earn in the other city to keep the same standard of living.
If you earn $100,000 in Boulder, you'd need $97,443 in Thornton to maintain your standard of living.
Climate, safety, and demographics side by side.
Thornton, CO is about 2.6% cheaper overall than Boulder, CO, based on our cost-of-living index. Housing costs are roughly 7% higher in Boulder than in Thornton. If you earn $80,000 in Boulder, you'd need about $77,955 in Thornton to keep the same standard of living.