About
US sleeper standards. Single: Twin/Twin XL. Couple: Queen minimum. King has more width than Cal King but Cal King is 4" longer (good for tall). Most modern bedrooms 12×14 ft fit a King. Smaller rooms: Queen.
Formula
Frequently asked questions
How accurate is the Mattress Size Comparison?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Mattress Size Comparison free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Can I use the Mattress Size Comparison on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum.
Does the Mattress Size Comparison work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
How do I report a bug or suggest improvement to the Mattress Size Comparison?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours.
Can I share results from the Mattress Size Comparison?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another mattress size comparison tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.
Is the Mattress Size Comparison accurate?
The Mattress Size Comparison applies the standard formula for mattress size comparison. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Mattress Size Comparison free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
How to use the Mattress Size Comparison
The Mattress Size Comparison is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Mattress Size Comparison-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
US mattress size reference
| Size | Width × Length | Area (sq in) | Best for |
|---|---|---|---|
| Twin | 38 × 75 | 2,850 | Child, single sleeper, bunk beds |
| Twin XL | 38 × 80 | 3,040 | Tall single sleeper, dorm rooms |
| Full / Double | 54 × 75 | 4,050 | Single adult who wants room, snug for two |
| Queen | 60 × 80 | 4,800 | Most couples, the best-selling US size |
| King | 76 × 80 | 6,080 | Couples wanting width, co-sleeping with kids |
| California King | 72 × 84 | 6,048 | Tall sleepers (4 inches longer than King) |
A Queen gives each person in a couple 30 inches of width, slightly less than a Twin each. A standard King splits into two 38-inch halves, matching a Twin per sleeper, which is why it is the comfort jump most couples notice. Cal King trades 4 inches of width for 4 inches of length, so it only makes sense if a sleeper is over about 6 feet 2 inches.
Buying pitfalls to avoid
- Forgetting the room clearance. Leave at least 24 to 30 inches of walking space on each side. A King needs a bedroom of roughly 12 by 12 feet; squeezing one into a 10-foot room blocks doors and dressers.
- Assuming King and Cal King share bedding. They do not. Cal King is narrower and longer, so sheets and frames are not interchangeable, and Cal King linens are harder to find in stores.
- Ignoring the box-spring and frame footprint. The mattress is only part of the package; a platform frame or adjustable base adds a few inches all round and changes how the bed fits through doorways and up stairs.
- Overlooking split options for adjustable bases. A Split King is two Twin XL mattresses side by side, letting each partner raise their own head or feet independently without disturbing the other.