Alnair 的投资回报率（ROI）计算器：含场景演示与按揭实例的实用指南
Why you’d use the ROI Calculator
ROI 计算器能快速把“一套不错的公寓”变成有数据支撑的投资故事。不再是模糊的承诺，而是向客户展示：该单元在选定期限内能赚多少钱，收入由哪些部分构成（租金 + 房价升值）、哪些成本会降低收益（管理费、额外开支，短租还包括运营费用），最重要的是——最终的 ROI。
此外，你可以模拟“如果……会怎样”的情景，并快速比较同一单元的长期与短期，这能加速决策并提升计算的可信度。
How to use the ROI Calculator in Alnair
1) Where to create a calculation
打开 project page / unit page（包含项目内的二级单元）。
找到 ROI Calculator 模块并点击 “Add calculation”。
你可以为同一单元创建 多种计算（例如“Base”、“Optimistic”、“Conservative”），以便为特定客户快速挑选合适情景。
2) Choose a strategy: Long-term or Short-term
Long-term rental — 适用于客户以 年租合同为思路：收入稳定，有明确的“年租”数值。
在此填写 市场年租，并使用 Market Scenario 展示“低于市场 / 市场价 / 高于市场”时会发生什么。
Short-term rental — 适用于客户希望做 按日出租。
此类收入取决于 日均价格和入住率，且必须包含 运营费用（管理费 + 平台费）。若不考虑这些费用，短租常常看起来不切实际地高收益。
3) Fill in unit details + shared inputs (the same for both strategies)
选择策略后，设置单元基础信息和通用计算设置。
Unit details (where the data comes from)
你可以 手动输入数值（便于“what-if”建模），或者
你可以从本楼/项目中 选择可用房源的单元 — 系统会自动填充该单元卡片中存在的 面积（sqm/ft²）及其他属性。之后只需添加情景输入。
Shared calculation inputs
T (years) — 计算周期（持有期）。
Unit Price — 购买价格（按该情景希望展示的数值）。
Service charge — 可按面积（费率 × 面积）或按年固定金额。
Extra expenses — 任何额外成本（家具、保险、维修、预备金等）。
税费默认不是单独输入项——若需要，请在 Extra expenses 中作为一行添加。Growth rate — 年化房价增值率（若不包含升值请使用 0）。
What you need to fill in depending on the strategy
A) Long-term: “contract rent” + market scenarios
Long-term strategy inputs
Market annual rental price — 市场年租
Market Scenario — 相对于市场的偏差（–15%、–10%、–5%、0%、+5%、+10%、+15%）
How Market Scenario works (client-friendly explanation)
Market Scenario 不是“复杂公式”，而只是一个情景切换：
0% — 按市场租价
–10% — 低于市场 → 收入降低 → ROI 降低
+10% — 高于市场 → 收入提高 → ROI 提高
其实际操作是对年租进行乘数调整：
–10% → × 0.90
0% → × 1.00
+10% → × 1.10
这样你能快速展示 2–3 个现实的版本：保守 / 基准 / 乐观。
B) Short-term: “daily rent” + operating fees
Short-term strategy inputs
Daily rental price — 日均租金
Occupancy rate — 入住率（预订天数比例）
Property management fee % — 管理费比例
Platform fee % — 平台/服务费比例
在短租中，这些费用被视为 运营成本，会显著影响 ROI，因此应明确向客户提示。
4) Where the client will see the result
保存计算后，ROI 指标可在计算器外部使用：
在 project/unit page 上 — 便于在电话或会面中实时解释逻辑。
在 PDF 演示文档中 — ROI 模块可包含在导出的 PDF 中；生成资料时可选择要展示的情景。
Calculation examples (so you can explain it “on the fingers”)
Example 1 — a simple long-term scenario (quick template)
Assume:
Purchase price: 1,200,000
Service charge over 5 years: 72,630
Extra expenses: 200,000
Market rent: 100,000/year, scenario 80% → 80,000/year, over 5 years 400,000
Appreciation: 5%/year for 5 years → 331,200
Then:
Total income = 400,000 + 331,200 = 731,200
Total cost = 1,200,000 + 72,630 + 200,000 = 1,472,630
ROI ≈ 49.7%
Example 2 — Mortgage (how to reflect it using Extra expenses)
Inputs
Unit price: 1,000,000 AED
Down payment: 200,000 AED
Loan amount: 800,000 AED
Interest rate: 5% per year
Loan term (example): 25 years
Payment type: annuity
Step 1. Calculate the monthly payment
For these terms, the monthly annuity payment is approximately:
≈ 4,676.72 AED / month
Step 2. Add mortgage to the calculator (cash-flow approach)
This is the simplest and most client-friendly approach: “how much do I actually pay the bank each month”.
In Alnair:
Extra expenses → Add expense
Name: Mortgage payment
Type: Fixed
Recurrence: Per month
Amount: 4,676.72 AED
The calculator will automatically scale it by 12 × T:
For T = 5 years: 4,676.72 × 12 × 5 = ≈ 280,603 AED
This amount is included in Total cost.
How to explain it to the client:
“We included the real monthly mortgage burden, so the ROI reflects the cash-flow picture.”
Step 3. Alternative (investment logic): include interest only
Sometimes the client says: “principal repayment isn’t really a cost — it increases my equity.”
In that case you can include interest only as the true cost of financing.
For the same terms over 5 years (reference numbers):
Total payments over 5 years: ≈ 280,603 AED
Interest portion: ≈ 189,245 AED
Principal repaid: ≈ 91,358 AED
Remaining loan balance after 5 years: ≈ 708,642 AED
How to add it:
Extra expenses → Add expense
Name: Mortgage interest (T years)
Type: Fixed
Recurrence: One-time
Amount: 189,245 AED
How to explain it to the client:
“We’re not counting principal repayment as an expense — only the financing cost (interest). This makes ROI closer to classic investment logic.”
Quick cheat sheet: which mortgage approach to use
Client asks “What will I pay each month?” → use monthly payment (cash-flow)
Client asks “What’s my financing cost / investment return?” → use interest-only
5 practical sales scenarios
Compare Long-term vs Short-term for the same unit.
Show 3 long-term rent scenarios via Market Scenario: below market / at market / above market.
Conservative case: appreciation = 0 and add a “reserve” expense in Extra expenses.
Optimistic case: rent +5–10% and appreciation +5%/year (when appropriate).
Mortgage: add mortgage payment (or interest) via Extra expenses and show ROI “with financing included”.