# Add Days to Date Calculator

> Add Days to Date Calculator is a paid API for AI agents from x402.forgemesh.io, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Adds or subtracts a number of days from a given date and returns the resulting calendar date with its weekday, or computes the number of days between two dates.

## Facts

- Endpoint: POST https://x402.forgemesh.io/add-days-to-date
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/add-days-to-date-calculator-2c237049
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_q0YErSSmws8Yi7ZCeu2fa

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability add-days-to-date-calculator-2c237049 -d '<json body>'
```

Example prompt: What date is exactly 90 days after March 15, 2025, and what day of the week does that fall on?

## When to prefer this

Use this endpoint when you need precise calendar date arithmetic — adding or subtracting a specific number of days from a date — and need the exact resulting date and weekday without risk of off-by-one errors that LLMs are prone to when counting days mentally. Ideal for deadline calculations, trial period end dates, contract term tracking, and reminder scheduling.

## Known failure modes

- Invalid ISO date format returns an error or unexpected result
- Missing both add_days and end date may return ambiguous or default output
- Extremely large day offsets may exceed supported date ranges
- Non-integer or malformed add_days string may cause parsing errors

## How this service works

Adds or subtracts a number of days from any date and returns the resulting calendar date plus its weekday, exact date arithmetic instead of the off-by-one errors that show up when a model counts days in its head. For deadline calculations, reminder scheduling, and contract term tracking.

## Output

Returns the resulting calendar date after adding or subtracting the specified number of days from the start date, along with the weekday name of the result. If an end date is provided instead of add_days, returns the number of days between the two dates.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "end": {
   "type": "string",
   "description": "ISO date — if set, returns days between"
  },
  "start": {
   "type": "string",
   "description": "ISO date (default now)"
  },
  "add_days": {
   "type": "string",
   "description": "days to add to start"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "calendar_days": 17,
  "business_days_weekdays_only": 13
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/add-days-to-date-calculator-2c237049/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.forgemesh.io](https://www.zero.xyz/host/x402.forgemesh.io/llms.txt)