We build small, useful corners of the internet.
Cozy River Studios is an independent, bootstrapped studio in Denver, Colorado. We run 100+ small calculator and guide websites, among them PlasmaPayCalculator, TheaterCalc and WorkshopCalc, and three weekly newsletters, built on one quiet idea: the web is at its best when it answers the question you actually came with.
There is a small, kind reason behind every site we have ever made.
Start with a question we asked first.
Every site begins with something we needed and couldn't quite find — the calculator, the guide, the answer. We build that first, for ourselves.
Tools that finish, not feeds that scroll.
Visitors come with a question. They leave with an answer. No infinite anything, no engagement loops — just the smallest useful thing, well made.
Design like a river — clear, calm, going somewhere.
Plain pages. Quiet typography. Numbers and words chosen with care. The aesthetic is craftsmanship; the goal is a friendly answer in under a minute.
The most-read calculators
Six calculators,
each quietly everywhere.
Picked by the numbers, not by mood. These are the studio's most-read tools, plus the newest one off the bench. Our top three sites were cited by Bing Copilot more than 300,000 times in 90 days.
RunBikeCalc
Pace, power, threshold. Training-zone and race-pace calculators that runners and cyclists bookmark and come back to.
ParentCalc
Honest cost calculators for the questions every parent asks at midnight: daycare, formula, a second child, a bigger car.
PlasmaPayCalculator
Plasma-donation pay rates and a center finder. Our most-cited site: about 200,000 Bing Copilot citations in 90 days.
ChildCarePath
Childcare costs, provider math, and the unsexy logistics of a family taking shape — ratios, budgets, and what to ask on the tour.
WorkshopCalc
Torque charts, drill-bit sizes, and project cost math for the small-shop builder. Cited by Bing Copilot about 45,000 times in 90 days.
RecoveryCalc
Sauna, cold plunge, sleep, and zone-2 math for people who take recovery as seriously as the workout. The newest build off the studio bench.
By the numbers · 2026
Partnership · Sponsorship · Custom builds
Bring your brand into the quiet company of small, useful pages.
Our readers arrive on purpose, with a question, and stay long enough to find the answer. That makes the studio's pages an unusually attentive place to put a brand. We work with a small number of partners each year, on terms that suit the writing.
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№ 01
Sponsored placements
Editorial partnerships on a single site or across the index, written in our voice.
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№ 02
Affiliate & review programs
Product guides on TestBeforeYouBuy, ParentCalc, RunBikeCalc and sister sites, researched from specs, standards and owner reviews.
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№ 03
Custom calculators & tools
Bespoke micro-tools for product teams who want the studio's care applied to their problem.