The short version
Set a crop box at the target ratio, scale or position that box over the original without changing the image's horizontal and vertical proportions, then export at sufficient dimensions. Crop changes the visible area; it should never require stretching.
What matters most
- The crop rectangle—not independent image scaling—sets the new ratio.
- Crop position is a creative decision after dimensions are calculated.
- Remaining pixels must still satisfy the delivery size.
How to apply it
- Confirm source width, height and orientation.
- Choose the exact destination ratio and minimum pixel dimensions.
- Calculate whether width or height must be removed.
- Position the ratio-locked crop around protected content.
- Export proportionally and inspect both composition and pixel size.
Reference table
| Source | Target | Largest centered crop | Removed |
|---|---|---|---|
| 6000 × 4000 (3:2) | 4:5 portrait | 3200 × 4000 | 46.7% width |
| 6000 × 4000 | 1:1 | 4000 × 4000 | 33.3% width |
| 4000 × 3000 (4:3) | 16:9 | 4000 × 2250 | 25% height |
| 1920 × 1080 (16:9) | 4:3 | 1440 × 1080 | 25% width |
Use exact dimensions and units in production notes; familiar labels can describe more than one standard.
Calculate the largest matching rectangle
For a target width:height ratio a:b, keeping the full source height gives crop width = source height × a ÷ b. Keeping the full width gives crop height = source width × b ÷ a. Use the candidate that fits within both source dimensions.
For 6000 × 4000 going to square, full-height crop width is 4000, so the largest square is 4000 × 4000. The crop removes 2000 horizontal pixels in total; a centered crop removes 1000 from each side, but position can be shifted.
- Calculate with full precision.
- Round final raster boundaries deliberately.
- Report total and per-edge removal separately.
Position the crop around protected content
Geometry identifies crop size, not crop position. Mark faces, products, text and directional movement before placing the rectangle. Preserve look room in front of a person and avoid tangencies that make important edges feel cramped.
When one crop cannot contain all protected elements, choose fit with background, redesign independent layers or create destination-specific compositions. Automatic subject detection is a starting point, not proof that the crop preserves the story.
- Protect meaning before symmetry.
- Leave intentional space around movement.
- Review automatic crops manually.
Check remaining pixels against delivery
A crop reduces the available raster even when retained pixels stay unchanged. A 6000 × 4000 source cropped to 3200 × 4000 for 4:5 portrait contains 12.8 MP, not the original 24 MP. Compare 3200 × 4000 with required display or print dimensions.
Downscale once from the accepted crop. If enlargement is necessary, inspect actual source detail and expected viewing distance rather than relying on a nominal pixel count. Sharpening may improve perception but cannot restore removed detail.
- Use post-crop dimensions.
- Avoid repeated export cycles.
- Evaluate print needs after composition is final.
Keep the workflow reversible
Use nondestructive crop metadata, masks or an editable document while composing. Export a derivative and retain the full original. This lets another platform, print size or client request use a different crop without enlarging the first result.
Record ratio, output dimensions and any bleed or safe-zone requirement. Reopen the exported file to verify orientation and pixel size; editor previews can hide rotation metadata or resampling choices.
Common mistakes to avoid
- Entering output width and height with unlocked proportions.
- Centering every crop despite an off-center subject.
- Ignoring required print bleed or interface-safe space.
- Judging only percentage loss instead of protected content.
Continue with the right tool
Use a calculator to check the numbers against your own source and destination instead of relying on a generic preset.
Related guides
Cropping vs Resizing an Image: What Actually Changes?
Understand how cropping and resizing affect composition, aspect ratio, pixel dimensions and quality so you can choose the correct operation.
Image cropping and print preparationHow Much of an Image Will Be Lost When Cropping?
Calculate crop dimensions, removed pixels and percentage area when fitting one image aspect ratio into another without distortion.
Image cropping and print preparationWhich Aspect Ratio Should You Use for Photography?
Choose between 3:2, 4:3, 4:5, 1:1 and panoramic photo ratios based on capture, composition, print and delivery needs.
Frequently asked questions
Does cropping stretch an image?
No. A proper crop removes pixels without changing the proportions of those retained.
How do I find the largest crop?
Hold the full source height or width, calculate the other dimension from the target ratio, and choose the result that fits inside both source bounds.
Is a centered crop always best?
No. Move the crop to protect the subject and intentional visual space.
Can I crop to a larger pixel size than the original?
Cropping cannot create pixels. Upscaling afterward interpolates a larger raster.