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Photo Aspect Ratio Calculator

The Photo Aspect Ratio Calculator helps photographers match their images to standard print sizes and social media dimensions. Compare print formats like 4×6, 5×7, 8×10, and 11×14, and calculate the exact crop needed to fit each frame without distortion.

Photo Aspect Ratio Calculator — Live Preview
Photo Ratio
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Proportion Solver
A : B = C : D — Enter any 3 values
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Results
Visual ratio breakdown
Solved Proportion
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Simplified
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Percentages
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Decimal
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Fraction
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Visual Ratio
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    Ratio Simplifier
    Reduce any ratio to its simplest form
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    Simplified Result
    Reduced to lowest terms
    Simplified Ratio
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    GCD Used
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    Percentages
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    Decimal Ratio
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    Fraction
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    Visual Ratio
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      Ratio Scaler
      Multiply a ratio by a scale factor
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      Scaled Result
      Ratio after scaling
      Scaled Ratio
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      Original
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      Factor
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      Percentages
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      Simplified
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      Visual Ratio
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        🕐 Recent Calculations

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        What is Photo Aspect Ratio?

        Photo aspect ratio determines how a photograph fits into print frames, social media formats, and digital displays. A photo shot in 3:2 (standard DSLR) must be cropped to 5:4 to fit an 8×10 frame, losing some content at the edges. Understanding photo ratios prevents unexpected cropping.

        Common photo print ratios include 3:2 (4×6 prints), 7:5 (5×7 prints), 5:4 (8×10 and 16×20 prints), and 7:5 (5×7 prints). Social media ratios differ: Instagram uses 1:1 and 4:5, Facebook covers use 205:78, and Pinterest pins use 2:3.

        Formulas & Equations Used

        This Photo Aspect Ratio Calculator uses the following core equations:

        1 Print Size to Aspect Ratio ▼
        Ratio = Print Width : Print Height (simplified)

        An 8×10 print has a ratio of 8:10 = 4:5. A 4×6 print has a ratio of 4:6 = 2:3.

        2 Crop Dimensions for Target Ratio ▼
        Crop Height = Image Width × (Target H / Target W)

        To crop a 6000×4000 photo to 5:4: Crop Height = 6000 × (4/5) = 4800. Since 4800 > 4000, crop width instead: Crop Width = 4000 × (5/4) = 5000.

        3 DPI Calculation for Print ▼
        DPI = Pixel Dimension / Print Size (inches)

        A 6000px wide image printed at 8 inches = 6000/8 = 750 DPI. For quality printing, DPI should be at least 300.

        How to Use This Photo Aspect Ratio Calculator

        Follow these 3 simple steps:

        1

        Enter Your Values

        Type the known values into the input fields above. The Photo Aspect Ratio Calculator accepts any positive numbers.

        2

        Choose Calculation Mode

        Select Solve, Simplify, or Scale mode in the calculator. Each applies different equations to your inputs.

        3

        View Results

        Click Calculate to see your answer with a visual ratio bar, pie chart, and step-by-step solution breakdown.

        Example Problems & Step-by-Step Solutions

        Here are 3 worked examples using this Photo Aspect Ratio Calculator:

        Example 1 Crop a 3:2 photo for an 8×10 (5:4) frame
        1 Photo: 6000 × 4000 (3:2)
        2 Target ratio: 5:4
        3 New width: 4000 × (5/4) = 5000 pixels
        4 Crop: remove 500px from each side
        ✓ Cropped photo: 5000 × 4000 pixels (5:4)
        Example 2 Calculate DPI for a 5×7 print from a 4200×3000 image
        1 Width DPI: 4200 / 5 = 840 DPI
        2 Height DPI: 3000 / 7 = 428.6 DPI
        3 Effective DPI: min(840, 428.6) = 428.6
        ✓ Print at 428.6 DPI — excellent quality
        Example 3 Find the crop for Instagram 4:5 from a 4:3 photo
        1 Photo: 4032 × 3024 (4:3)
        2 Target height for 4:5: 4032 × (5/4) = 5040
        3 5040 > 3024, so crop width instead
        4 New width: 3024 × (4/5) = 2419.2 ≈ 2419
        ✓ Cropped photo: 2419 × 3024 pixels (4:5)

        Frequently Asked Questions

        What aspect ratio is a 4×6 photo? ▼

        A 4×6 photo has an aspect ratio of 2:3 (or 3:2 in landscape). This matches the standard 35mm camera sensor ratio, so DSLR photos fit 4×6 prints perfectly without cropping.

        Why do my photos get cropped when printing 8×10? ▼

        Most cameras shoot in 3:2 ratio, but 8×10 prints use 4:5 ratio. The 3:2 is wider, so the sides get cropped to fit the narrower 4:5 frame. Always review the crop preview before printing.

        What is the best aspect ratio for portrait photography? ▼

        4:5 is popular for portrait photography as it provides more vertical space for head-to-waist framing. It maps perfectly to 8×10 and 16×20 print sizes and is Instagram's preferred portrait format.

        How do I resize photos for multiple social media platforms? ▼

        Create crops at each platform's native ratio: 1:1 for Instagram feed, 4:5 for Instagram portrait, 9:16 for Stories/Reels, 16:9 for YouTube thumbnails, and 2:3 for Pinterest pins.

        What resolution is needed for a large format print? ▼

        For prints larger than 24 inches, 150-200 DPI is acceptable because viewers stand farther back. A 24×36 poster at 150 DPI needs 3600×5400 pixels (about 19 MP).

        Learn About Ratios

        What is a ratio?

        A ratio is a comparison between two or more quantities showing the relative size of one to another. Written as A : B, it means 'for every A units of the first quantity, there are B units of the second.' For example, a ratio of 3 : 4 means for every 3 parts of A, there are 4 parts of B. Ratios are used in cooking, construction, finance, science, and everyday life.

        How do I solve a proportion?

        A proportion is an equation that says two ratios are equal: A : B = C : D. To solve for a missing value, use cross-multiplication. If D is unknown: D = (B × C) / A. This works because in equal ratios, the cross products are always equal: A × D = B × C. Our Proportion Solver does this automatically — just enter any 3 values and it finds the 4th.

        How do I simplify a ratio?

        To simplify a ratio, find the Greatest Common Divisor (GCD) of both numbers and divide each by it. For example, 24 : 36 — the GCD of 24 and 36 is 12. So 24 ÷ 12 = 2 and 36 ÷ 12 = 3, giving the simplified ratio 2 : 3. Our Simplifier automatically finds the GCD and reduces your ratio to its lowest terms.

        What is ratio scaling and when is it useful?

        Scaling a ratio means multiplying both parts by the same factor to create an equivalent, larger (or smaller) ratio. For instance, scaling 2 : 5 by a factor of 3 gives 6 : 15. This is extremely useful for recipes (tripling a recipe), construction (scaling blueprints), mixing solutions, or any scenario where you need to maintain the same proportion at a different magnitude.

        What's the difference between a ratio and a fraction?

        A ratio A : B compares two quantities to each other (part-to-part), while a fraction A/B typically represents a part-to-whole relationship. However, any ratio can be expressed as a fraction: 3 : 4 is equivalent to 3/4 = 0.75. The key difference is context — ratios compare quantities side-by-side, while fractions represent a portion of a total.