Beach Tide Calculator

Beach Tide Calculator estimates tide height at a specific time using high tide height, low tide height, their respective times, and the target time, based on a simplified sinusoidal model for semi-diurnal tides.

Date (YYYY-MM-DD): Enter date in YYYY-MM-DD format

Time (HH:MM): Enter time in 24-hour HH:MM format

Latitude (°): Latitude of beach (-90 to 90)

Longitude (°): Longitude of beach (-180 to 180)

Formulas Used

Tide height is estimated using a simplified sinusoidal model based on the M2 tidal constituent (principal lunar semidiurnal).

Tide Height:
\\[ H(t) = A \cdot \sin\left(\frac{2\pi}{T}(t – t_0)\right) + M \\]

Where:
- \\( H(t) \\): Tide height (meters) at time \\( t \\)
- \\( A \\): Amplitude (meters, adjusted by latitude)
- \\( T \\): Tidal period (12.42 hours for M2 tide)
- \\( t \\): Time since reference (hours)
- \\( t_0 \\): Phase offset (hours, adjusted by longitude)
- \\( M \\): Mean sea level (meters, assumed 0 for simplicity)

Example Calculations

Example 1: Santa Monica Beach

Inputs: Date = 2025-07-27, Time = 14:30, Latitude = 33.94, Longitude = -118.40

Calculations:

Time since reference (2025-07-27 00:00): \\( t = 14.5 \, \text{hours} \\)
Amplitude: \\( A = 1 + 0.01 \cdot |33.94| = 1.3394 \, \text{m} \\)
Phase offset: \\( t_0 = 0.05 \cdot (-118.40) = -5.92 \, \text{hours} \\)
Tide height: \\[ H = 1.3394 \cdot \sin\left(\frac{2\pi}{12.42} \cdot (14.5 – (-5.92))\right) \approx 1.3394 \cdot \sin(9.88) \approx 1.33 \, \text{m} \\]

Result: Tide Height ≈ 1.33 m

Example 2: Miami Beach

Inputs: Date = 2025-07-27, Time = 08:00, Latitude = 25.79, Longitude = -80.13

Calculations:

Time since reference: \\( t = 8.0 \, \text{hours} \\)
Amplitude: \\( A = 1 + 0.01 \cdot |25.79| = 1.2579 \, \text{m} \\)
Phase offset: \\( t_0 = 0.05 \cdot (-80.13) = -4.0065 \, \text{hours} \\)
Tide height: \\[ H = 1.2579 \cdot \sin\left(\frac{2\pi}{12.42} \cdot (8.0 – (-4.0065))\right) \approx 1.2579 \cdot \sin(6.08) \approx 1.25 \, \text{m} \\]

Result: Tide Height ≈ 1.25 m

Example 3: Sydney Beach

Inputs: Date = 2025-07-27, Time = 18:00, Latitude = -33.87, Longitude = 151.21

Calculations:

Time since reference: \\( t = 18.0 \, \text{hours} \\)
Amplitude: \\( A = 1 + 0.01 \cdot |-33.87| = 1.3387 \, \text{m} \\)
Phase offset: \\( t_0 = 0.05 \cdot 151.21 = 7.5605 \, \text{hours} \\)
Tide height: \\[ H = 1.3387 \cdot \sin\left(\frac{2\pi}{12.42} \cdot (18.0 – 7.5605)\right) \approx 1.3387 \cdot \sin(5.29) \approx 1.32 \, \text{m} \\]

Result: Tide Height ≈ 1.32 m

How to Use the Calculator

Follow these steps to estimate tide height at a beach:

Enter Date: Input the date in YYYY-MM-DD format (e.g., 2025-07-27).
Enter Time: Input the time in 24-hour HH:MM format (e.g., 14:30).
Enter Latitude: Input the beach latitude (-90 to 90, e.g., 33.94).
Enter Longitude: Input the beach longitude (-180 to 180, e.g., -118.40).
Calculate: Click “Calculate Tide Height” to see the result.
Interpret Result: The result shows the estimated tide height with calculations.
Share or Embed: Use the share buttons to post results on social media, copy the result, or get an embed code.

Note: This is a simplified model using the M2 tidal constituent. Actual tide heights depend on multiple tidal components, local geography, and weather. For accurate predictions, consult official tide tables or NOAA/equivalent services.