Recovery

Sweat Rate Calculator

Calculate your personal sweat rate from pre/post-exercise weigh-ins, estimate fluid and sodium losses, and get hydration recommendations using ACSM guidelines.

Sweat Rate Results

1.3 L/hr

Mild Dehydration

Total fluid lost: 1.3 L · Body weight loss: 1.1%

Hydration Metrics

Sweat rate, total fluid lost, and recommended hourly replacement.

Sweat rate

1.3 L/hr

Total lost

1.3 L

Replace /hr

1050 mL/hr

Breakdown

Weight lost: 0.8 kg (1.1%)
Recommended fluid intake: 1050 mL/hr
Est. sodium loss: 1196 mg/hr

Recommendation

You lost 1.1% body weight. Mild dehydration can slightly reduce performance. Increase fluid intake by ~1050 mL/hr next session.

Formula: ACSM/GSSI standard — sweat rate = (pre − post + fluid consumed − urine) / duration.

How to use it

Open Sweat Rate Calculator and enter your current baseline accurately.
Adjust one variable at a time so changes are easy to interpret.
Review the headline output first, then inspect supporting metrics.
Run at least one conservative and one aggressive scenario.
Use outputs to set your next training or nutrition action for the week.
Save or share this setup if you want to revisit it later, then check one easier and one harder version before you change your plan.

AI Integrations

Contract, discovery endpoints, and developer notes for agent use.

Always available for agents

Tool contract JSON

https://aifithub.io/contracts/sweat-rate-calculator.json

Stable input and output contract for this exact tool.

Human review

People can use the browser page to sense-check outputs and charts, but agents should still execute against the contract and discovery endpoints.

/agent-tools.json - machine-readable tool index.
/llms.txt - human-readable model discovery guide.
/.well-known/webmcp.json - WebMCP capabilities manifest.
/.well-known/ai-plugin.json - plugin-style discovery manifest.

{
  "tool": "sweat_rate_calculator",
  "pre_weight_kg": 70,
  "post_weight_kg": 69.2,
  "duration_minutes": 60,
  "fluid_consumed_ml": 500,
  "urine_produced_ml": 0
}

Open tool contract JSON Open AI integrations guide

Expand developer notes

Agent playbook

Resolve Sweat Rate Calculator from /agent-tools.json and open its contract before execution.
Validate inputs against the contract schema instead of scraping labels from the page UI.
Open the browser page only when a person wants to review charts, assumptions, or related tools.

Agent FAQ

Should ChatGPT, Claude, or another agent click through the UI?

No. Start with /agent-tools.json, then follow the tool's contract URL. The page UI is for human review, not parameter discovery.

When do tools show Quick and Advanced?

Every tool opens in Quick Start first. Advanced Controls keeps the same scenario, reveals more assumptions or diagnostics, and every tool keeps AI integrations inline below the instructions.

When should an agent still open the browser page?

Open it when a human wants to sense-check the output, review the chart, or keep exploring related tools after the calculation finishes.

Questions people usually ask

What is sweat rate?

Sweat rate is the volume of fluid lost through sweating per hour of exercise, measured in litres/hour. Average endurance athletes sweat 0.5–2.5 L/hr; heavy sweaters can exceed 3 L/hr in heat.

Which formula is used?

The ACSM (American College of Sports Medicine) standard formula: Sweat Rate (L/hr) = (Pre-weight − Post-weight + Fluid consumed − Urine produced) / Duration in hours. Each 1 kg body weight loss equals approximately 1 litre of sweat.

How do I weigh myself accurately?

Weigh yourself nude immediately before exercise, then nude again immediately after — before eating or drinking anything post-exercise. Use the same scale both times.

Do I need to track urine output?

For most workouts under 90 minutes, urine output is negligible and you can leave it at 0. For ultra-endurance events, tracking urine output improves accuracy.

Why does sodium loss matter?

Sweat contains sodium (average ~920 mg/L). High sweat rates deplete sodium faster, risking hyponatremia in long events. If you lose more than 800 mg/hr, consider electrolyte drinks or salt tabs.

Is this tool free and private?

Yes. AI Fit Hub tools are free, browser-based, and no-signup. Your inputs stay in your browser.

Does this replace a sports dietitian?

No. These outputs are evidence-based estimates. For personalised hydration plans, especially for elite performance or medical conditions, consult a registered sports dietitian.

Related Resources

Learn the decision before you act

Every link here is tied directly to Sweat Rate Calculator. Use the explanation, formula, examples, and benchmarks to pressure-test the calculator output from first principles.

Browse all 16 resources

Guides · 1 Checklists · 1 Tips · 4 Mistakes · 2 Formulas · 2

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