Find the right mattress topper for how you actually sleep.
Answer seven plain questions and get the thickness, material and firmness for your body, plus the sheet depth your bed will need once it's on.
Find my topperThe calculator needs no account.
- 01
Tell us how you sleep and what's wrong with the bed.
- 02
We work out the thickness and firmness your body needs.
- 03
We match current toppers and show you what sheets will still fit.
Your sleep. Your fit.
Tell us about your bed
Seven simple detailsWe change the comfort layer.
Not the mattress underneath.
A little extra comfort. Just enough.
Pick a sleep position to start
Your topper spec and sheet depth will take shape here. Change any answer to see the difference.
No guesswork. No account needed.Not a black box. Here is the math.
This is an editorial shopping guide, not a clinical formula or a guarantee of comfort. Your bed and personal preferences still matter. We have not slept on these models.
| Sleep position | Under 130 lb | 130-200 lb | 200-260 lb | Over 260 lb |
|---|---|---|---|---|
| Side | 2 | 3 | 3 | 4 |
| Back | 2 | 2 | 3 | 3 |
| Stomach | 1 | 1 | 2 | 2 |
| Mixed | 2 | 3 | 3 | 3 |
A small plushness change or a sagging mattress caps the depth at 2 inches. Sagging also stops product recommendations: a topper is not a repair. Stomach sleepers and people over 260 lb start at medium-firm; side sleepers up to 200 lb start soft; everyone else starts medium.
Latex shopping ranges: soft 14-22, medium 23-30, medium-firm 30-38 ILD / 25% IFD. Memory-foam density ranges: under 130 lb, 3-4 lb/ft³; 130-260 lb, 4-5 lb/ft³; over 260 lb, 5-6 lb/ft³. These are broad starting ranges. Density is not firmness; indentation tests also vary between makers.
Material points start at memory foam 3, latex 2, ventilated gel foam 2. Sleeping hot adds 4 to latex and 3 to gel, and subtracts 2 from memory foam. Partner movement adds 5 to memory foam and 4 to gel. Highest points wins; a tie favors memory foam, then latex.
Sheet target = mattress height + topper + a 1-inch fit allowance, rounded up to a currently researched maximum mattress-fit capacity. While research is unavailable, we round up in 2-inch shopping increments and label that as provisional. Unknown mattress height uses an explicitly estimated 12 inches.
Model score: exact material 30 points (another memory-foam family gets 18); exact depth 30; size 15; maker firmness 10; density or ILD in range 10; washable cover 5. Missing data earns no points. At least 75 points, exact depth and size, compatible material, and no known firmness conflict are required. An unpublished firmness is not an endorsement of its feel. Equal scores sort alphabetically. No price, commission or AI opinion affects the score.
Background reading: Polyurethane Foam Association: foam performance ↗. Manufacturer sources and timestamps appear with the live results.
Every bed, in one place.
Save a named bed from the calculator, then take one purchase list shopping. Profiles stay in this browser, not your account. Export a backup before clearing browser data.
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A firm new bed.
A side sleeper.
A softer landing.
180 lb · sleeps hot · 12-inch queen mattress
- 01
Start with 3 inches. Our side-sleeper table gives the 130-200 lb band more cushioning depth than stomach sleeping.
- 02
Choose ventilated latex, soft feel. Heat shifts the material points to latex. The shopping target is 14-22 ILD / 25% IFD, plus a washable stretch cover.
- 03
Plan for 16-inch sheets or deeper. 12 + 3 = 15 inches of bed. Add our 1-inch fit allowance: look for a maker-rated 16-inch-or-greater mattress-fit capacity.
Before you add
another layer.
Can a topper fix a sagging mattress?
No. A topper follows the surface beneath it; it cannot rebuild a worn support core. Check the base and measure the dip with nobody on the bed. Around 1.5 inches is our conservative replace-first flag, not a universal warranty threshold. Even a smaller sag can be a problem. We do not recommend buying a topper to repair a sag.
What does density actually mean, and why do listings hide it?
Density is the weight of a cubic foot of foam, not how hard it feels. It is one durability clue, not a lifespan guarantee. Firmness is measured separately with indentation force. Makers do not always publish these measurements, and we cannot know why. We show the missing fact rather than guessing it from shipping weight or the phrase ‘high density’.
Will 4 inches sleep hotter?
More foam and a deeper hug can make heat escape harder, but thickness alone cannot predict your temperature. Cover, room temperature, ventilation and bedding all matter. Our heat preference shifts toward ventilated latex; if motion is also a concern, it favors ventilated gel memory foam. Gel is not a promise of cooler sleep.
Will my sheets still fit?
Measure the mattress and add the topper and any thick protector. Our calculator adds a 1-inch shopping allowance, then rounds up to a researched sheet-fit capacity when available. Check ‘fits mattresses up to’ on the actual sheet listing; a raw pocket measurement and a maximum mattress-fit height are not always the same.
Does this work on a bed-in-a-box?
Yes, if the mattress is fully expanded, flat and still supportive. A topper changes the comfort surface, not the core underneath. Check your mattress maker’s care instructions, expansion time and trial terms before changing the setup. For a new bed that is fundamentally wrong for you, a return may be the better choice.
How do you pick the models?
We research current manufacturer specifications in two material families, cache the findings for 48 hours, then score the models with the published local formula. AI does not rank the products. We have not slept on any of these. A match is based on published specs only, not a test result or a guarantee that you will like it. Check the current price, rating, exact variant and return terms on Amazon.
A note on how we keep this free
As an Amazon Associate we earn from qualifying purchases. We may earn a commission if you buy through our Amazon links, at no extra cost to you. That never changes your fit score. Links open a search for the exact model and variant, not an invented product listing. We show no prices, ratings, review counts or bestseller claims. Please check the current details and return terms before purchasing.