Membership: every tool is free today 会员：今天所有工具都免费
All 28 calculators and 15 guides are fully unlocked — no paywall, no account, no feature limits, now or as a hidden charge later. 28 个计算器与 15 篇指南全部开放——无付费墙、无需账号、无功能限制，今天如此，以后也不会变成隐形收费。
| Capability能力 | Free, right now当前免费版 | Possible future Pro未来可能的 Pro |
|---|---|---|
| All 28 calculators, every formula全部 28 个计算器与公式 | ✓ | Same — core math stays free相同——核心计算永久免费 |
| Bilingual English / 中文中英双语 | ✓ | ✓ |
| Offline PWA + local save离线 PWA + 本地保存 | ✓ | ✓ |
| Printable plans & checklists可打印计划单与清单 | ✓ | ✓ |
| All 15 in-depth field guides全部 15 篇深度指南 | ✓ | ✓ |
| Cloud sync across devices跨设备云同步 | — | Exploring (opt-in, account required)探索中（可选，需账号） |
| Saved trip-plan archive & PDF packs行程计划归档与 PDF 包 | — | Exploring探索中 |
| Guide / course expansions指南/课程扩展内容 | — | Possible premium extras可能的增值内容 |
| Advertisements广告 | Only if AdSense is configured; no ads currently仅在配置 AdSense 后展示；当前无广告 | Ad-free无广告 |
Our pricing promise
1. Safety math is never paywalled. The calculators on this site are decision aids for situations where money must not be a factor. Dosing drops, wind chill, CPR tempo, lightning distance and SAR trip plans will remain free for everyone.
2. No bait-and-switch. Anything published as free stays free for the published page. A future Pro tier may add convenience features — sync, archives, expanded learning — but never remove existing capability.
3. No dark patterns. No nag screens, no fake urgency, no selling your email. The site is supported by optional advertising (only when Google AdSense is actually configured, with your consent) and, later, by a clearly labelled Pro plan.
Join the waitlist
Pro does not exist yet, and there is nothing to pay for. If you want to be consulted about what it should include — and told before anything launches — open the button below, which creates an email to zjp133@outlook.com. We reply personally, usually within a few days.
我们的定价承诺
1. 安全计算永不设墙。本站计算器用于金钱不应成为门槛的场景：投药滴数、风寒、心肺复苏节拍、闪电测距与搜救行程单，将永久对所有人免费。
2. 不搞“先免费后收费”。已免费发布的功能将继续免费。未来的 Pro 可能增加的是便利性功能——云同步、归档、扩展学习——而绝不是收走已有能力。
3. 不玩暗黑模式。没有弹窗轰炸、没有虚假紧迫、不出售你的邮箱。本站靠可选广告（仅在真正配置 Google AdSense 且经你同意后展示）以及未来明确标注的 Pro 计划维持。
加入候补名单
Pro 尚不存在，目前没有任何需要付费的东西。如果你希望参与功能讨论、并在上线前得到通知，请点击下方按钮，会给 zjp133@outlook.com 新建一封邮件。我们会亲自回复，通常几天内。
Join the Pro waitlist by email发邮件加入 Pro 候补 Keep using the free tools继续使用免费工具