---
title: "Goal phases"
description: "Bulk, cut, or maintain at a planned weekly rate, with calories set from your own logs and a check on whether you're on pace."
---

A goal phase is a block of time with one direction for your bodyweight: a
**bulk**, a **cut**, or **maintenance**. You pick how fast to gain or lose,
skcal sets your calories for that rate, and Today tells you whether your weigh-ins
are keeping pace.

## Start a phase

On **Today**, open the phase card and tap **Start a phase**, or tell the agent
("starting a lean bulk", "time to cut till March"). Only one phase is open at a
time. Starting a new one ends the current one the day before.

Everything except the type is optional:

| Field | If you leave it out |
| --- | --- |
| Rate (% bodyweight per week) | Bulk +0.25%, cut -0.5%, maintain 0% |
| Start weight | Your latest weigh-in |
| Planned end | Open-ended |
| Goal weight | Projected from the start weight, rate, and planned end |
| Daily calories | Estimated from your logs (see below) |
| Daily protein | Your current target |

Rates go from -2% to +2% a week. A bulk needs a positive rate and a cut a
negative one. The agent picks +0.25 to +0.5% for a bulk and -0.5 to -1% for a
cut unless you name one.

Starting or editing a phase writes its calories, protein, goal weight, and dates
into your [targets](/docs/quickstart#3-set-your-targets), so the rest of skcal
tracks against the new numbers.

## Calories from your own data

When you don't give a calorie number, skcal estimates your maintenance from the
last 28 days. It takes your average logged intake and adjusts it by how much
your weight actually moved over the same stretch. That accounts for your real
metabolism and logging habits, not a formula. It then adds the surplus or
deficit your rate implies.

:::note
The estimate needs at least 10 logged days and weigh-ins spanning 14 days. With
less, your calories stay where they were. The agent will work out a number from
your height, weight, and activity instead, or you can enter one.
:::

## Are you on track?

The phase card compares your planned weekly change with your actual one. The
actual rate is a trend line through every weigh-in since the phase started, so
one heavy morning doesn't throw it off. After the first week it shows one of:

- **On track**: within a third of the planned rate either way (within ±0.15% a
  week for maintenance).
- **Too fast**: gaining faster than planned in a bulk, or losing faster in a cut.
- **Too slow**: anything short of the planned rate.

Until there's a week of weigh-ins it shows **Tracking**. Ask the agent "am I
gaining too fast?" and it answers from the same numbers.

## From the API and MCP

Phases live under `/api/phases`: list, start, edit, end, and delete. Keys need
the `targets:read` or `targets:write` scope. `GET /api/phases` returns every
phase with its progress, plus your current maintenance estimate.

```bash
curl -X POST https://app.skcal.fit/api/phases \
  -H "Authorization: Bearer skcal_your_key_here" \
  -H "content-type: application/json" \
  -d '{"kind": "bulk", "ratePctPerWeek": 0.25, "plannedEndDate": "2027-03-01"}'
```

The [MCP server](/docs/mcp-server) exposes the same operations as
`skcal_get_phases`, `skcal_start_phase`, `skcal_update_phase`, and
`skcal_end_phase`. See the **Phases** section of the
[API reference](/docs/api-reference/introduction) for every field.