## Present Value and Future Value Interest Factor Tables
### Why These Tables Exist
Time-value-of-money calculations reduce to repeated multiplication/division by discount or growth factors. Rather than computing `(1+r)^n` or `1/(1+r)^n` from scratch every time, exam bodies pre-compute these four standard factors and present them as look-up tables.
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### The Four Factors at a Glance
| Symbol | Full Name | Formula | Reads as… |
|---|---|---|---|
| PVIF(r,n) | Present Value Interest Factor | `1 / (1+r)^n` | ₹1 received n years from now is worth this much today at rate r |
| PVIFA(r,n) | PV Interest Factor of Annuity | `[1 − 1/(1+r)^n] / r` | ₹1 received at the end of each year for n years is worth this much today |
| FVIF(r,n) | Future Value Interest Factor | `(1+r)^n` | ₹1 invested today grows to this amount in n years at rate r |
| FVIFA(r,n) | FV Interest Factor of Annuity | `[(1+r)^n − 1] / r × (1+r)` | ₹1 deposited at the beginning of each year accumulates to this amount |
> Critical footnote distinction:
> PVIFA assumes payments at the end of each period (ordinary annuity / annuity-immediate).
> FVIFA assumes payments at the beginning of each period (annuity-due).
> This asymmetry is baked into ICAI's published tables — never assume both use the same convention.
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### How to Read the Tables
1. Locate the column for the interest rate `r` (e.g., 10%).
2. Locate the row for the number of periods `n` (e.g., 5 years).
3. The cell value is your factor.
4. Multiply that factor by the cash-flow amount.
Example read: PVIF(10%, 5) = 0.621 → ₹1 five years from now = ₹0.621 today.
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### Relationship Between Single-Period and Annuity Factors
$$\text{PVIFA}(r,n) = \sum_{t=1}^{n} \text{PVIF}(r,t)$$
Each PVIFA row value equals the cumulative sum of PVIF values up to that year — so PVIFA(10%, 3) = PVIF(10%,1) + PVIF(10%,2) + PVIF(10%,3) = 0.909 + 0.826 + 0.751 = 2.487 ✓
Similarly, FVIFA(r,n) is the accumulated sum of FVIF values (annuity-due convention).
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### Quick Sanity Checks
- PVIF values are always < 1 (discounting shrinks value).
- FVIF values are always > 1 (compounding grows value).
- Higher `r` → lower PVIF, higher FVIF.
- PVIF(r,n) × FVIF(r,n) = 1 always (they are reciprocals).
- PVIFA(r,n) increases with more years; PVIFA(r,∞) = 1/r (perpetuity formula).