A ceiling of at least 600 feet and a visibility of two statute miles if the airport has a precision approach (ILS Approach) A ceiling of at least 800 feet and a visibility of two statute miles if the airport has a non-precision approach (RNAV/GPS or VOR)

The "600-2 800-2" rule is a modern, simplified adaptation of Naismith’s Rule, a classic formula used by hikers and mountaineers to estimate travel time in rugged terrain. Specifically, the metric version of the rule suggests that you should allow 1 hour for every 5 kilometers (approx. 3 miles) of forward progress, plus an additional 1 hour for every 600 meters (approx. 2,000 feet) of vertical ascent. In 2026, many hiking clubs refine this for different fitness levels: a fit hiker might use a "5-600" base, while a slower group or those with heavy packs might use a "4-450" ratio. The rule is vital for safety, as it prevents hikers from being caught on a mountain after dark; for example, a 10km hike with 1,200m of climbing would be calculated as 2 hours for distance plus 2 hours for height, totaling 4 hours of active walking time. This does not include stops for food or photography, so most 2026 "Route Cards" add an extra 15–20% buffer to the final Naismith calculation to ensure a safe and enjoyable return.

The “600 2 800 2 rule” is a guideline used in real estate investing, specifically for evaluating rental properties. It’s a quick, back-of-the-napkin calculation to see if a property’s numbers are worth a deeper look.

Here’s what it means:

• 600 2: A property should rent for at least $600 per $100,000 of its purchase price.
• 800 2: A property should rent for at least $800 per $100,000 of its purchase price.

The “2” in the name simply refers to the two different thresholds (600 and 800).

How to Use the Rule:

1. Take the property’s purchase price.
2. Divide by 100,000.
3. Multiply that number by 600 and then by 800.
4. The result gives you a target monthly rent range.

Example: For a property listed at $400,000: $400,000 / $100,000 = 4 4 x 600 = $2,400 (minimum target rent) 4 x 800 = $3,200 (strong target rent)

According to the rule, this $400,000 property should generate between $2,400 and $3,200 in monthly rent to be considered a good potential investment.

Purpose & Interpretation:

• The $600 Rule ($600 per $100k): This is often considered the minimum threshold for a property to potentially break even or be cash flow neutral after expenses (mortgage, taxes, insurance, maintenance, vacancy). If the rent is below this, it’s likely a negative cash flow property.
• The $800 Rule ($800 per $100k): This is the target for positive cash flow. A property