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Dimension Comparison Tool
Compare the size of two objects visually and numerically — pick phones from our database or enter your own dimensions — with a to-scale drawing and percentage differences per axis.
Relative size (to scale)
Apple iPhone 18 Pro Max
77.6 × 163 mm × 8.3
Custom item
15 × 7.5 mm × 0.8
- Width difference
- -135.2%77.6 vs 15
- Height difference
- -182.4%163 vs 7.5
- Depth difference
- -164.8%8.3 vs 0.8
- Front-face area difference
- -196.5%12,648.8 vs 112.5
Custom item is -135.2% narrower than Apple iPhone 18 Pro Max on width. Percentages use the symmetric difference formula (divided by the average of both values).
How This Tool Works
Object A defaults to a phone from our database (official millimetre dimensions); Object B can be another phone or any custom item you measure yourself. The tool draws both shapes to the same scale, then computes the symmetric percentage difference for width, height, depth and front-face area.
Scale drawing does the perceptual work numbers cannot: a 6% width difference looks like a hairline on screen; a 40% difference looks like a different class of device. Use the drawing for intuition and the percentages for precision.
How to Use It
For phone-vs-phone, select a model on both sides. For anything else — a laptop sleeve vs a laptop, a TV vs a wall space, two smartwatches — switch a side to Enter dimensions and type width, height and depth in millimetres (any consistent unit works; the drawing is unitless-ratio based).
Depth is optional; width and height drive the drawing and the primary differences. All dimensions should use the same unit.
Understanding the Results
Percentages use the symmetric formula (|A − B| ÷ average × 100), so neither object is treated as the baseline — consistent with our Percentage Difference Calculator.
Front-face area multiplies width × height for both objects and compares the products: useful for ‘how much bigger does the screen face look’ questions where both dimensions grow together.
Worked Example
Samsung Galaxy S25 at 146.9 x 70.5 x 7.2 mm and 162 g against OnePlus 13 at 162.9 x 76.5 x 8.5 mm and 213 g. The tool draws both outlines to scale and reports the gaps: 16 mm taller (about 11%), 6 mm wider (about 8.5%), 1.3 mm thicker (about 18%) and 51 g heavier (about 31%).
Scaled side by side, the width difference reads as a hairline while the weight difference does not - which is the point. The Galaxy fits pockets and one-handed reach that the OnePlus does not, and no single figure on either spec sheet says so until the two are placed next to each other.
Important Considerations
Phone dimensions come from manufacturer specification records (sources and verification dates on each product page). Custom dimensions are yours — measure at the widest points.
The drawing is 2D and proportional; it ignores weight, thickness perception beyond the depth number, bezels vs body, and curved edges.
If you are checking whether something fits a space rather than comparing two objects, the Fit & Clearance Checker answers that directly.
Methodology & Data
- Database dimensions: design.dimensions {height, width, depth} in mm from manufacturer spec sheets.
- Percentage difference: |A − B| ÷ ((|A| + |B|) ÷ 2) × 100 per axis; area uses width × height products.
- Scale drawing: each axis normalized to the larger of the two objects (min 24 px rendering).
- Custom inputs accept any positive numbers in a consistent unit; invalid/missing values block the comparison with an explicit message.
Related Tools
Related Guides
- Understanding Product Dimensions Before You Buy
How to read height, width and depth specifications — and convert millimetres into real-world fit for pockets, bags, desks, shelves and wall spaces.
- How to Compare Product Specifications the Right Way
A practical method for comparing spec sheets: which numbers matter, which are marketing, and how to weight differences before you buy.
Common Questions
How does the tool draw the two objects?
Both sides share one pixels-per-millimetre scale, so an object that is 3 mm taller is visibly taller in the drawing. Percentage differences for width, height, depth and face area are reported beside the drawings.
How much bigger is A than B in percent?
The tool computes the symmetric percentage difference per axis: the gap divided by the average of both values. Neither object is treated as the baseline.
Can I compare non-phone items?
Yes — switch either side to Enter dimensions and type your own measurements in millimetres (or any unit, as long as both sides match).
What unit should I use?
Millimetres are shown by default and match our phone records. Inches work for custom entries as long as both objects use the same unit — the math is unit-agnostic.
Will this tell me if something fits my shelf?
Not directly — this tool compares two objects to each other. The Fit & Clearance Checker compares an object against a space with clearance requirements.