Tools
Each of these does one thing, runs entirely in your browser, and sends nothing anywhere. They exist because the answer people actually need is usually one step past what the obvious tool gives them — the rounding error, not just the number; the effective cost, not the headline price.
Aspect Ratio Calculator
Find the missing width or height for any ratio — and see what your rounding did to the ratio, which most calculators hide.
Image Resizer
Resize to a target size with cover or contain. The file never leaves your device; the work happens in your browser.
Color Contrast Checker
Check text against WCAG AA and AAA — and when it fails, see how far each colour has to move to pass, with the corrected value ready to copy.
Video File Size & Bitrate Calculator
Duration, bitrate and file size in both directions, including audio — and both the binary and decimal megabyte, because upload limits disagree about which one they mean.
Cloud Storage Effective Cost Calculator
Storage price per TB is not what you pay. See your effective cost including egress, and the read volume at which the cheapest provider stops being cheapest.
Meeting Time Finder Across Time Zones
Score every half-hour slot against each participant's stated working hours, see who is carrying the compromise, and get the date of the first repeat that a daylight-saving change moves.
Baking Ingredient Weight Converter
King Arthur Baking and America's Test Kitchen disagree by 18% on a cup of flour. See both figures and the spread instead of one number presented as fact.
Screening Workload & Cost Calculator
Reviewer-hours, calendar time and cost for systematic-review screening — with dual-independent conflict resolution broken out as its own line, not buried in one average.
Dimensional Weight (DIM) Shipping Calculator
Carriers bill the larger of actual and dimensional weight. No hardcoded divisor table to go stale — you enter your carrier's, with one verified, dated example included.
Photo Print Crop Calculator
Enter your photo's shape and see the exact percentage — and which edge — every standard print size crops, ranked from least crop to most.
Podcast Hosting Bandwidth & Break-even Calculator
Downloads-based, hard-capped, and flat-unlimited plans aren't comparable by price alone. Enter your show's numbers and each plan's own terms to see the real cost and where the ranking flips.
Coffee-to-Water Ratio Comparator
Stumptown, Counter Culture and Intelligentsia's own brew guides disagree by about 8% on pour-over ratio. See what each one means for your dose, side by side, instead of one unattributed number.
Turkey Roasting Time Comparator
Butterball, Jennie-O and Honeysuckle White's own roasting charts disagree by up to 38% for the same weight bird at the same 325°F oven. See all three side by side instead of one averaged number.
Wetsuit Thickness Comparator
Rip Curl, O'Neill and Billabong's own temperature guides disagree by a full thickness step at the same water temperature. See what each one recommends side by side instead of one blended chart.
Ski Wax Temperature Comparator
Swix, Toko and Fast Wax don't even agree on what their own color names mean — Toko's "Blue" is rated for -30°C to -10°C, Swix's "Blue" for -12°C to -6°C. See each brand's own recommendation for your snow temperature.
Cookware Oven-Safe Temperature Comparator
All-Clad's own steel body handles 600°F but its own glass lid tops out at 350°F. Enter your oven temperature and see which named brands' own parts — body, lid, or knob — actually clear it, ranked by headroom.
Knife Sharpening Angle Comparator
Wüsthof's own page says 14°. Shun's own page says 16°. Enter the angle your sharpener is actually set to and see which named brands' own stated edge angles it matches, ranked by how close.
Resistance Band Color Comparator
TheraBand's own page rates "Red" at 3.7 lbs, one of its lightest bands. Fit Simplify's own page rates "Red" at 25-30 lbs, its heaviest. Enter a target resistance and see which named brands' own colors actually match.
Cooler Ice Retention Claim Comparator
Igloo claims 3, 5 or 7 days by product line. ORCA claims 8-14 days by size. YETI's own FAQ refuses to give a number at all, citing no industry test standard. Enter your trip length and see which named brands' own claims actually cover it.
Guitar String Gauge Label Comparator
D'Addario's own page and Elixir's own page both call 12-53 "Light." Ernie Ball's own page calls that same word "Custom Light" — its own "Light" is 11-52. Enter the two gauges you play and see what each brand's own label actually matches.
Umbrella Wind Rating Comparator
Frankford's own page states eleven different wind ratings for eleven named umbrella models, from 15 mph to 50 mph. Tuuci's own two pages don't even agree with each other. Enter the wind speed you expect and see which named models actually clear it.
Bike Lock Security Rating Comparator
ABUS rates locks 1-15. Kryptonite rates locks 1-10. Sold Secure, an independent tester, rates them Bronze to Diamond. None of these convert into each other. Describe your situation and see what each system's own page actually recommends, side by side.
Space Heater Coverage Claim Comparator
Every plug-in heater tops out at the same 1500 watts — the same ~5,118 BTU/hr by definition. Lasko's own page still claims 300 sq ft of coverage; Pelonis's own page claims 107.6 sq ft for a different model. Enter your room size and see which named brands' own claims actually cover it.
Kayak Weight Capacity Comparator
Old Town's own page publishes a lower "usable" figure next to its "total" capacity. Eddyline's own page says there's no industry standard for that gap at all. Hobie's own page rates its seat 150 lb below the hull. Enter your weight and gear and see which named kayaks' own numbers actually cover you.
Phone Case Drop Protection Claim Comparator
Pelican's own page claims 16ft. Spigen's own page claims 4ft. Both call it "military-grade" — a term no agency certifies or checks. Enter the drop height you're worried about and see which named brands' own current claims actually cover it.
Portable AC BTU Coverage Comparator
A 2017 federal rule standardized how brands must state cooling power (SACC) specifically to stop apples-to-oranges comparisons. Black+Decker's and Midea's own pages still claim 150 sq ft for a 5,000 BTU SACC unit; Whynter's own page claims 400 sq ft for the identical rating. Enter your room size and see which named brands' own current claims actually cover it.
Recovery Strap Safety Rating Comparator
Rhino USA's own page states a working load limit AND a separate breaking strength, 3x apart. Smittybilt's own page states one number and calls it only a "rating." Bubba Rope's own FAQ says there's no working load limit at all. Enter the weight of what you're recovering and see what each named brand's own current page actually tells you.
Generator Noise Level Claim Comparator
Champion's own page admits there's no industry standard for generator noise testing, then states its figure at 23 ft. Yamaha's own page states a load-percentage range instead, with no distance at all. Enter the loudest noise you can tolerate and see which named brands' own current claims actually clear it — and on what basis.
Whole-House Humidifier Coverage Claim Comparator
GeneralAire's own two current models both state 17 gallons a day under the identical stated test basis — and claim 4,200 and 2,800 square feet, 1,400 sq ft apart. Honeywell's own spec table labels a cubic-feet number "Building Square Footage." Enter your home's size and see which named brands' own current claims actually cover it.
Backpack Volume Claim Comparator
Zpacks' own page claims 42L main body for the Arc Blast. Treeline Review's independent bean-fill test measured 34L — 19% less. Gossamer Gear's own claim for the Mariposa 60 undersells what the same test measured, in the opposite direction. Enter the volume you need and see which named packs' own claims actually agree with an independent measurement.
Trailer Hitch Class Weight Rating Comparator
CURT's own Class 3 hitch for the GMC Canyon states 8,000 lb GTW — 2,000 lb more than two Class 4 hitches checked, Draw-Tite's and Reese's own 6,000 lb models. Enter the trailer weight you need to tow and see which named, specific hitches actually cover it, not just which class they're labeled.
Ceiling Fan Blade Span Comparator
Hunter's own guide and Big Ass Fans' own guide both say a 52" fan covers a 200 sq ft room. Kichler's own guide says that same room already needs 56" or larger. Enter your room's square footage and see what each named brand's own current guide actually recommends.
Cut-Resistant Glove Rating Comparator
ANSI/ISEA 105 rates gloves in grams-force, A1 to A9. EN 388 rates the same kind of test in Newtons, A to F. HexArmor's own page says an ANSI A4 and an EN 388 Level D "are not the same rating." Enter a glove's actual test force and see exactly where it lands on both scales.
Coffee Maker "Cup" Size Comparator
KitchenAid's own page says a "cup" on its carafes is 4.75 oz. Bunn's, Ninja's and Black+Decker's own pages each work out to 5.00 oz — and all four are well under a real 8 oz measuring cup. Enter your machine's labeled cup count and see what it actually brews, brand by brand.
Knife Steel Hardness (HRC) Comparator
Zero Tolerance's own page puts CPM S35VN at 60-62 HRC. Chris Reeve Knives' own FAQ puts the identical named steel at 59-60 HRC. Enter the hardness your knife's maker states and see which named brands' own current numbers for that steel actually agree.
Wine & Champagne Bottle Size Name Comparator
Millésima's own page says a Champagne Jeroboam is 3 liters. Château Rioublanc's own page says a Bordeaux Jéroboam is 5 liters — 66.7% bigger, for the identical word. Pick the name printed on your bottle and see what it means in each region's own convention.
Skateboard Wheel Durometer Comparator
Bones' own page says its B scale "reads 20 points lower" than A — an 84B wheel isn't softer than a 92A wheel, it's about 104A once converted, harder than anything else on the page. Enter what's printed on your wheel and see where it actually lands next to Bones, Ricta and OJ's own current numbers.
Surge Protector VPR Rating Comparator
CyberPower's own page states 600V clamping voltage for both its 1,500-joule and 3,000-joule surge protectors — double the joules, identical protection rating. Enter the standardized VPR you'll accept and see which named products' own current pages actually meet it, not which one advertises the biggest joule number.
Paper Shredder Security Level (DIN 66399) Comparator
Aurora's own page calls a P-4 shredder "Micro-Cut." Fellowes' and HSM's own pages reserve that exact word for P-5, a finer level, and call P-4 "Cross-Cut" instead. Enter the DIN 66399 level you're trying to match and see which named products' own current pages actually state it.
Blender Motor Power Comparator
Vitamix's own page states 2.2 peak HP and no watts at all. Ninja's own page states both 1,200 continuous and 1,400 peak watts on the same spec table. Breville's own page states 1800 watts with no peak/continuous label. Enter the number printed on your blender's box and see where it actually ranks once everything shares a basis.
Gas Grill Heat Density Comparator
Weber's own page states more total main-burner BTU for the Genesis E-435 (48,000) than Broil King states for the Baron 420 Pro Shadow (40,000) — but a lower BTU per square inch of actual grate (74.3 vs. 87.0). Enter your own grill's main burner BTU and primary cooking area and see where it really ranks.
Water Filter Pitcher Replacement Comparator
Brita's own page and PUR's own page each give one fixed filter life no matter your water. ZeroWater's own chart instead ties the identical filter's life to your tap water's TDS — from 40+ gallons down to 8 or fewer. Enter your household's daily use and TDS and see what each brand's own current claim actually predicts for you.
Suitcase Capacity Claim vs. Box Volume Comparator
Briggs & Riley's own page claims 41L for a case whose own stated dimensions work out to 40.8L of box — already 100.5% of it. it luggage's own listing claims 43L against a 42.6L box — 101%. Enter your own suitcase's dimensions and claimed capacity and see where it actually lands.
Fishing Rod Power Label Comparator
PENN's own page rates its "Medium" spinning rod for 12-20 lb line. Abu Garcia's own page rates its "Medium" for 6-12 lb — PENN's Medium starts exactly where Abu Garcia's ends. Enter the line weight you actually use and see which named brands' own power labels match.
Office Chair Weight Capacity Comparator
Steelcase's own Gesture states 400 lb. IKEA's own Markus states 276 lb. Neither is marketed as "big and tall" — that's a 45% gap between two brands' idea of ordinary. Enter your weight and see which named chairs' own current pages actually cover it.
Trampoline Weight Capacity Comparator
Springfree's own page states a 220 lb "single-jumper limit," full stop. Skywalker's own page states 400 lb for a similarly sized round trampoline — and computes its own structural rating as exactly four times that. ACON's own page states no single-user limit at all for its biggest models. Enter your weight and see which named trampolines' own current pages actually cover it.
Standing Desk Weight Capacity Comparator
UPLIFT's own page states 355 lb for its standard dual-motor frame. IKEA's own IDÅSEN page states 154 lb for the complete desk — less than half. IKEA's own two pages for that same desk don't even agree with each other, 11 lb apart. Enter what you're putting on the desk and see which named brands' own current pages actually cover it.
Gun Safe & Fire Safe Fire Rating Comparator
Browning's own page claims 155 minutes at 1,200°F. SentrySafe's own page claims 30 minutes at 1,550°F — a hotter, independently-verified UL Classified test. Enter the protection you want and see which named products' own current pages actually cover it, and on what basis.
Insulated Drinkware Temperature Retention Comparator
Stanley's own page claims "stays cold for 15 Hrs." Cold compared to what temperature? It doesn't say. Zojirushi's own pages instead publish the actual measured temperature at 6 and 24 hours. Enter how long and how cold or hot you need it, and see which named products' own claims can even answer the question.
Paint Sheen Gloss Level Comparator
MPI's own published standard defines "Eggshell" as 10-25 gloss units. PPG's own data sheet for a product it names Eggshell reports a reading its own sheet calls "Semi-gloss" — 39-45 units, entirely outside the Eggshell band. Enter a gloss reading and see which official level it actually falls under, and which named products' own numbers agree with the name on the can.
Air Purifier CADR Coverage Comparator
AHAM Verifide independently tests CADR, and AHAM's own "2/3 rule" turns that into a square-footage figure. Coway's own page states 1,680 sq ft for its Airmega Mighty, computed at 1 air change an hour — and 361 sq ft elsewhere on the same page. Enter your room size and see which named products' own stated CADR actually clears AHAM's own math.
Tripod Load Capacity Comparator
Manfrotto's own page admits its old "Max Payload" figure "sometimes" skips safety margins entirely — the same kind of figure Benro's and Vanguard's own pages still publish today. Only Manfrotto and Gitzo currently certify their number to a published test, UNI/PdR 105:2021. Enter your camera-and-lens weight and see which named tripods' own current pages actually cover it, and on what basis.
Jump Starter Engine Coverage Comparator
NOCO's and GOOLOO's own pages both claim 9.0L gas / 7.0L diesel for a 3000A jump starter. DBPOWER's own page claims 8.0L / 6.0L for its own 3000A model — and 10.0L / 8.0L for another DBPOWER product also labeled 3000A. Enter your engine's size and see which named products' own current claims actually cover it, not just which one shouts the biggest amp number.
Hammock Weight Capacity Comparator
ENO's own FAQ rates its SingleNest and DoubleNest hammocks identically at 400 lb. Kammok's own pages do the same at 500 lb for Roo Single and Roo Double. But ENO's and Kammok's own straps pages state a lower figure for their ultralight lines — pair the wrong two and the system holds less than either page alone says. Enter your weight and see which named combinations actually cover it.
Treadmill Weight Capacity Comparator
Bowflex's own T9 and Sole's own F65 — each brand's higher-tier home model — state the identical 350 lb. NordicTrack's own page states one flat 400 lb across four differently priced models, while Horizon Fitness's own line steps up in four stages from 300 to 375 lb. Enter your weight and see which named treadmills' own current pages actually cover it.
E-Bike Motor Power Claim Comparator
Federal law caps a legal e-bike motor at "less than 750 watts" and never says nominal or peak. Aventon's own page states 750W nominal and 1440W peak for the same motor. Engwe's own current spec table for one model states only the 960W peak figure, no nominal number at all. Enter what's printed on yours and see where it lands.
Drone Sub-250g Registration Threshold Comparator
The FAA's own rule exempts recreational drones at "0.55 pounds or less" — 249.48 g, not the round "250 grams" everyone repeats. DJI's own Mini 3 page states 248 g standard and "approximately 290 g" with its own optional bigger battery, same drone. Enter your own weight plus any accessories and see where it lands.
Pressure Washer Cleaning Units (CU) Comparator
Real cleaning power is PSI × GPM, called Cleaning Units — but the name on the box is only PSI. Ryobi's own 2500 PSI model (1.2 GPM, 3,000 CU) beats its own 2700 PSI model (1.1 GPM, 2,970 CU) on Ryobi's own current pages. Enter your own numbers and see where they actually rank.
Dog Crate Interior Space Comparator
Carlson's own page states its 36-inch crate fits a dog up to 30 inches long. Petmate's own page for its differently-built, identically-labeled 36-inch kennel gives 32.5 inches of interior room instead — while Petmate's own next size down misses that same dog by half an inch. Enter your dog's own length and height and see which named crates actually have room.
Rowing Machine Weight Capacity Comparator
Concept2's own RowErg page states two maximums for the identical machine: "500 lb as tested by Concept2," and "300 lb as tested per" the European EN 20957-7 standard, right alongside it. Every review site quotes only the higher number. Enter your weight and see which named rowers' own current pages actually cover it.
Exercise Bike Weight Capacity Comparator
Current indoor cycling bikes cluster into three flat bands. Sole's own site is the only one that explains the split: its base-tier upright and recumbent both state 300 lb, its "light commercial" tier of the same two bike types both state 350 lb — 50 lb that tracks the tier, not the bike type. Enter your weight and see which named bikes actually cover it.
Stroller Weight Capacity Comparator
Joovy's own page states 75 lb for its jogging stroller. Thule's own page states 49 lb for its jogging stroller — a 53% gap for the same job. UPPAbaby, Bugaboo and Chicco all converge on exactly 50 lb. Enter your child's weight and see which named strollers' own current pages actually cover it.
Drywall Anchor Weight Rating Comparator
Cobra Anchors' own page states two numbers per anchor — pull-out and shear, up to 2.5x apart for the same anchor. Toggler's own page states only one, no shear figure at all. OOK's own page states one number and never says which kind of load it's for. Enter what you're hanging and see what each named anchor's own current page actually tells you.
Why these are here
We looked at where a small independent site can still be genuinely useful rather than out-published. In several high-traffic areas the top results are not articles about tools — they are the tools. Writing about them would be pointless; building one is not.
So these are a test as much as a service. If they turn out to be useful to people, more will follow. The reasoning behind how we choose what to build is in how we test.