FOV Calculator — instantly compute horizontal, vertical, and diagonal field of view for any aspect ratio or unit (deg/rad).
Switch between Game FOV and Lens/Sensor modes to match screens, simulators, and camera sensors — with live conversions and coverage.
Perfect for sim racing & FPS players, photographers, and creators who need precise, reproducible FOV settings in seconds.
FOV Calculator – Games & Lenses
• v-locked: Keeps vFOV constant and recalculates the resulting hFOV and dFOV.
• d-locked: Keeps dFOV constant (lens equivalence) and recalculates the corresponding hFOV and vFOV.
🎯 FOV Calculator – Convert Horizontal, Vertical & Diagonal Field of View Instantly
Our free Field of View Calculator helps you convert between horizontal, vertical, and diagonal FOVs for any aspect ratio — perfect for gamers, developers, and photographers.
The tool includes three precise modes: Horizontal FOV for wide monitors, Vertical FOV for VR and portrait views, and Diagonal FOV for full-screen and lens coverage. Each adjusts automatically based on your selected aspect ratio.
Switch easily between modes to visualize camera sensors, monitor setups, or game perspectives — and understand how your field of view changes in real time.
🧮 How the Field of View Calculator Works (with Aspect Ratio Conversion)
The FOV Calculator uses geometric trigonometric formulas to relate your screen or lens dimensions to the resulting field of view angle. It instantly converts between horizontal (hFOV), vertical (vFOV), and diagonal (dFOV) based on your chosen aspect ratio — for example, 16:9 or 21:9 ultrawide.
Core formula for FOV conversion:
FOV = 2 × arctan( (dimension ÷ 2) ÷ focal_length )
When switching aspect ratios (e.g. from 16:9 to 21:9), the perceived width expands horizontally while vertical FOV remains constant — unless you toggle between v-locked and d-locked modes.
- V-Locked: Keeps the vertical FOV fixed and recalculates horizontal/diagonal values — perfect for gaming monitor conversions.
- D-Locked: Keeps the diagonal FOV fixed and redistributes the angle based on width/height — ideal for optical lens and camera setups.
This flexible system makes it a true aspect ratio FOV converter, ideal for developers, gamers, and cinematographers working across different screen formats.
🎮 FOV Calculator for Sim Racing & FPS Games
The FOV Calculator is a favorite among sim racing and first-person shooter (FPS) players. It lets you calculate your exact in-game field of view across different aspect ratios and screen setups — from iRacing and Assetto Corsa to Arma 3 and ACC (Assetto Corsa Competizione).
Changing your FOV between 16:9 and 21:9 screens can dramatically affect your sense of speed, distance, and corner visibility. The table below shows how horizontal and vertical FOV shift across formats:
💡 Pro Tip: For sim racing, keep your vertical FOV realistic — between 55° and 65° — to maintain proper scale and depth perception. A lower FOV feels faster but can distort distances.
🔗 Try our Mouse Sensitivity Converter to match your FOV and DPI settings across games for perfect aim consistency.
📷 Camera FOV Calculator – Convert Field of View to Focal Length
The Camera FOV Mode helps photographers, filmmakers, and engineers calculate how focal length and sensor size affect the final field of view. Whether you use a Full Frame (36×24 mm), APS-C, or Micro Four Thirds camera, the calculator shows exactly how wide your lens sees at any distance.
It’s based on the geometric relationship between sensor width, focal length, and field of view:
FOV = 2 × arctan( (sensor_dimension / 2) ÷ focal_length )
For example, a 50mm lens on a Full Frame camera gives ~39.6° horizontal FOV, while the same lens on APS-C (1.6× crop) gives only ~25.4° — meaning a narrower view.
🔭 Use this mode for telescope FOV calculations or any optical system that depends on focal distance and sensor coverage — all results update instantly with your selected parameters.
🧩 Understanding Horizontal, Vertical & Diagonal FOV
The field of view (FOV) is measured in three key ways — horizontal (hFOV), vertical (vFOV), and diagonal (dFOV). Each type describes how wide or tall the visible area appears on your screen, camera, or headset, depending on the viewing setup.
- Horizontal FOV (hFOV): The width of the visible image — the most common FOV used in gaming and cinematography. A wider hFOV enhances peripheral vision but can slightly distort edges.
- Vertical FOV (vFOV): The visible height — crucial in VR and photography when shooting in portrait or head-mounted views. Adjusting vFOV maintains scale realism in simulation setups.
- Diagonal FOV (dFOV): The overall viewing angle measured from corner to corner. It’s used for lenses, sensors, and monitor specifications to represent the total coverage area.
All three values are linked by trigonometric relationships based on your aspect ratio. The calculator automatically synchronizes them, allowing instant switching from hFOV to vFOV or dFOV without manual formulas.
💡 A visual diagram can help illustrate how the three FOV angles relate within a frame — horizontally across the screen, vertically top-to-bottom, and diagonally across the corners. (Recommended to add an infographic here later.)
🌌 Telescope FOV Calculator – Measure Sky Coverage Accurately
The Telescope FOV Calculator extends the same precision formulas used in photography and applies them to astronomy and telescopic systems. It determines how much of the night sky your telescope or binoculars can see through a given eyepiece or camera sensor.
The relationship between focal length and field of view is expressed as:
FOV (°) = 57.3 × (Sensor Size ÷ Focal Length)
For example, with a 22 mm sensor and a 1000 mm telescope focal length, your horizontal FOV is approximately:
FOV = 57.3 × (22 ÷ 1000) ≈ 1.26°
This means your telescope can capture an area of about 2.5× the apparent size of the Moon — a narrow but detailed view ideal for planetary or deep-sky imaging. By adjusting the focal length or sensor width, you can widen or narrow your visible sky coverage precisely.
🔭 Use this astronomy field of view calculator to plan telescope imaging sessions, determine eyepiece suitability, or simulate sky coverage before observation.
❓ FOV Calculator FAQs
1. What is FOV and how is it calculated?
FOV (Field of View) describes how much of a scene or image is visible through your camera, display, or game view. It’s calculated using trigonometric formulas like:
FOV = 2 × arctan( (dimension ÷ 2) ÷ focal_length )
2. How to convert vertical FOV to horizontal FOV?
Simply enter your vertical FOV and aspect ratio (like 16:9). The calculator will instantly compute the corresponding horizontal FOV using geometric conversion.
3. What is the difference between v-locked and d-locked?
In v-locked mode, the vertical FOV remains constant while width expands with screen ratio. In d-locked, the diagonal FOV stays fixed — ideal for lens or optical comparisons.
4. Can I use this tool for iRacing or Assetto Corsa?
Yes — the FOV Calculator supports game-specific conversions used in iRacing, Assetto Corsa, Arma 3, and other simulators. Adjust the aspect ratio or FOV mode to match your in-game configuration.
5. Is this FOV Calculator free to use?
Absolutely. This is a 100% free online FOV calculator — no registration, ads, or restrictions. You can use it anytime to convert camera, lens, or game FOVs instantly.
🚀 Optimize Your View with the FOV Calculator
The FOV Calculator was built for creators who see beyond the numbers — whether you’re a developer tuning aspect ratios, a photographer optimizing lens coverage, or a gamer chasing the perfect immersive setup. This free Field of View Tool delivers instant, accurate conversions for horizontal, vertical, and diagonal angles across screens, cameras, and telescopes.
Enhance your precision and explore more visual utilities on PixelsCalculator that complement this tool:
- 🎯 Mouse Sensitivity Converter – match DPI and FOV settings across games.
- 🧮 Aspect Ratio Calculator – compute width/height proportions precisely.
- 📏 Pixel Density Calculator – find PPI and pixel size for your screens.
Each tool is crafted with accuracy, simplicity, and love for detail — helping you make smarter visual and design decisions.
🔗 Explore official FOV documentation on Unity Manual or Unreal Engine Wiki for more in-depth understanding of field of view principles.