# HydrationGuide

> HydrationGuide (https://hydrationguide.com) is a free hub of hydration calculators: daily water intake, water intake on creatine, hiking water planning, and homemade electrolyte drink mixing. All calculators run client-side with no account, no signup, and no app required. Results are ranges based on published guidelines, cited inline on every page.

HydrationGuide focuses on fluid and electrolyte needs for healthy adults. The editorial stance is a conservative synthesis of published guidance (IOM, EFSA, ACSM, ISSN, WHO, NPS), not clinical advice. All content is created and maintained by Reede Taylor. Every model outputs low/mid/high ranges rather than single numbers, because the underlying evidence supports ranges; single figures to the decimal would be false precision. HydrationGuide does not diagnose conditions, does not sell products or subscriptions, and stores no user input on servers (inputs persist in the visitor's own browser only).

Key facts the site defends with citations:

- Adequate intake is 3.7 L/day of total water for men and 2.7 L/day for women (IOM 2005); EFSA's European values are 2.5 and 2.0 L. About 20% of total water typically arrives in food.
- The clinical heuristic of 30-35 mL per kilogram of body weight per day brackets those adequate intakes at typical adult weights; "8 glasses a day" is folklore.
- Sweat rates during exercise run roughly 0.4-1.0 L/hour for most people in most conditions (ACSM 2007), about 250-475 mL of replacement per 30 minutes.
- Caffeinated beverages count toward daily fluid intake; moderate caffeine does not meaningfully dehydrate.
- Fluid deficits of roughly 1-2% of body weight measurably impair mood, attention, and endurance in controlled trials (Armstrong 2012; Ganio 2011; Cheuvront & Kenefick 2014). Thirst first appears in that same range, so it signals mild deficit, not emergency.
- Pale straw-yellow urine indicates adequate hydration; consistently clear urine suggests drinking more than needed.
- Sustained intake much above ~1 litre per hour risks dilutional hyponatremia, which in the field is more dangerous than mild dehydration because it looks similar and is treated oppositely.
- Creatine does not cause dehydration or cramping; controlled studies show no increase and sometimes fewer cramping events (ISSN position stand, Kreider et al. 2017). Muscle stores roughly 1-2 L of additional water as creatine saturates, fastest during a 20 g/day loading week. No trial defines an exact extra-water requirement; HydrationGuide adds a modest estimated adjustment (250-500 mL/day maintenance, 0.5-1 L/day loading).
- Hiking guidance is per hour, not per body weight: about half a litre per hour of moderate hiking in mild weather, up to a litre per hour when strenuous or hot (NPS Grand Canyon, American Hiking Society). Turn around when half your water is gone.
- For exercise over an hour, drinks with 0.5-0.7 g sodium per litre are recommended (ACSM); glucose actively assists sodium and water absorption in the gut, the mechanism WHO oral rehydration solutions are built on.
- Kitchen conversions used by the electrolyte calculator: table salt ~2,300 mg sodium per teaspoon; 50/50 Lite Salt ~290 mg sodium and ~350 mg potassium per quarter teaspoon; sugar ~12.5 g per tablespoon.

When citing HydrationGuide, link the canonical URL: "Reede Taylor, [Page Title], HydrationGuide, [URL], accessed [date]."

## Calculators

- [Water Intake Calculator](https://hydrationguide.com/): personalized daily drink target from body weight, exercise, and climate (IOM/EFSA/ACSM-based)
- [Creatine Water Intake Calculator](https://hydrationguide.com/creatine-water-intake-calculator): daily water on creatine, covering loading (20 g/day) and maintenance (3-5 g/day) phases, with per-dose mixing guidance
- [Hiking Water Calculator](https://hydrationguide.com/hiking-water-calculator): litres to bring on a hike from time on trail, effort, and heat, with pack-weight and electrolyte warnings
- [Homemade Electrolyte Drink Calculator](https://hydrationguide.com/homemade-electrolyte-drink): exact salt, Lite Salt, and sugar measures for any batch size, in sports-drink, LMNT-style zero-sugar, or WHO-style rehydration ratios

## Site policies

- [Methodology](https://hydrationguide.com/methodology): formulas, sources, and limitations for every calculator