diff --git a/package-lock.json b/package-lock.json
index b9e5be8..e90e15a 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -3148,6 +3148,11 @@
       "resolved": "https://registry.npmjs.org/bulma/-/bulma-0.8.2.tgz",
       "integrity": "sha512-vMM/ijYSxX+Sm+nD7Lmc1UgWDy2JcL2nTKqwgEqXuOMU+IGALbXd5MLt/BcjBAPLIx36TtzhzBcSnOP974gcqA=="
     },
+    "bulma-switch": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/bulma-switch/-/bulma-switch-2.0.0.tgz",
+      "integrity": "sha512-myD38zeUfjmdduq+pXabhJEe3x2hQP48l/OI+Y0fO3HdDynZUY/VJygucvEAJKRjr4HxD5DnEm4yx+oDOBXpAA=="
+    },
     "bytes": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/bytes/-/bytes-3.1.0.tgz",
diff --git a/package.json b/package.json
index 4e47b60..1761179 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "@types/bs58": "^4.0.1",
     "bs58": "^4.0.1",
     "bulma": "^0.8.2",
+    "bulma-switch": "^2.0.0",
     "preact": "^10.3.1",
     "preact-jsx-chai": "^3.0.0",
     "preact-markup": "^2.0.0",
diff --git a/src/components/editable-text/index.tsx b/src/components/editable-text/index.tsx
index 010e345..82dadab 100644
--- a/src/components/editable-text/index.tsx
+++ b/src/components/editable-text/index.tsx
@@ -8,7 +8,7 @@ export interface EditableTextProps {
     class?: string
     editIconClass?: string
     onChange?: (value: string) => void
-    render: (value: string) => ComponentChild
+    render?: (value: string) => ComponentChild
 }
 
 const EditableText: FunctionalComponent<EditableTextProps> = ({ onChange, value, render, ...props }) => {
@@ -45,7 +45,7 @@ const EditableText: FunctionalComponent<EditableTextProps> = ({ onChange, value,
                     </div>
                 </div> :
                 <Fragment>
-                    { render(internalValue) }
+                    { render ? render(internalValue) : <span>{internalValue}</span> }
                     <i class={`${style.editIcon} icon ${props.editIconClass ? props.editIconClass : ''}`} onClick={onEditIconClick}>🖋️</i>
                 </Fragment>
             }
diff --git a/src/components/editable-text/style.css b/src/components/editable-text/style.css
index 6349e65..11cb78c 100644
--- a/src/components/editable-text/style.css
+++ b/src/components/editable-text/style.css
@@ -1,5 +1,5 @@
 .editableText {
-    display: inherit;
+    display: inline-block;
 }
 
 .editableText > * {
diff --git a/src/components/estimation-range.tsx b/src/components/estimation-range.tsx
index 671cfe0..efe9a42 100644
--- a/src/components/estimation-range.tsx
+++ b/src/components/estimation-range.tsx
@@ -9,13 +9,17 @@ export interface EstimationRangeProps {
 
 export const EstimationRange: FunctionalComponent<EstimationRangeProps> = ({ project, estimation, sdFactor }) => {
     const roundUp = getRoundUpEstimations(project);
-    const e = roundUp ? Math.ceil(estimation.e) : estimation.e;
-    const sd = roundUp ? Math.ceil(estimation.sd * sdFactor) : (estimation.sd * sdFactor);
+    let e = roundUp ? Math.ceil(estimation.e) : estimation.e;
+    let sd = roundUp ? Math.ceil(estimation.sd * sdFactor) : (estimation.sd * sdFactor);
     const max = e+sd;
     const min = Math.max(e-sd, 0);
+    if (!roundUp) {
+        sd = sd.toFixed(2);
+        e = e.toFixed(2);
+    }
     return (
         <Fragment>
-            <abbr title={`max: ${max}, min: ${min}`}>{`${e} ± ${sd}`}</abbr>&nbsp;<ProjectTimeUnit project={project} />
+            <abbr title={`max: ${max.toFixed(2)}, min: ${min.toFixed(2)}`}>{`${e} ± ${sd}`}</abbr>&nbsp;<ProjectTimeUnit project={project} />
         </Fragment>
         
     );
diff --git a/src/hooks/use-project-reducer.ts b/src/hooks/use-project-reducer.ts
index be89e1e..2756357 100644
--- a/src/hooks/use-project-reducer.ts
+++ b/src/hooks/use-project-reducer.ts
@@ -1,5 +1,5 @@
 import { Project } from "../models/project";
-import { Task, TaskID, EstimationConfidence } from "../models/task";
+import { Task, TaskID, EstimationConfidence, TaskCategoryID, TaskCategory } from "../models/task";
 import { useReducer } from "preact/hooks";
 
 export interface Action {
@@ -11,13 +11,19 @@ export type ProjectReducerActions =
     RemoveTask |
     UpdateTaskEstimation |
     UpdateProjectLabel |
-    UpdateTaskLabel
+    UpdateTaskLabel |
+    UpdateParam |
+    UpdateTaskCategoryLabel |
+    UpdateTaskCategoryCost |
+    AddTaskCategory |
+    RemoveTaskCategory
 
 export function useProjectReducer(project: Project) {
     return useReducer(projectReducer, project);
 }
 
 export function projectReducer(project: Project, action: ProjectReducerActions): Project {
+    console.log(action);
     switch(action.type) {
         case ADD_TASK:
             return handleAddTask(project, action as AddTask);
@@ -33,6 +39,21 @@ export function projectReducer(project: Project, action: ProjectReducerActions):
 
         case UPDATE_TASK_LABEL:
             return handleUpdateTaskLabel(project, action as UpdateTaskLabel);
+
+        case UPDATE_PARAM:
+            return handleUpdateParam(project, action as UpdateParam);
+
+        case ADD_TASK_CATEGORY:
+            return handleAddTaskCategory(project, action as AddTaskCategory);
+        
+        case REMOVE_TASK_CATEGORY:
+            return handleRemoveTaskCategory(project, action as RemoveTaskCategory);
+
+        case UPDATE_TASK_CATEGORY_LABEL:
+            return handleUpdateTaskCategoryLabel(project, action as UpdateTaskCategoryLabel);
+        
+        case UPDATE_TASK_CATEGORY_COST:
+            return handleUpdateTaskCategoryCost(project, action as UpdateTaskCategoryCost);
     }
 
     return project;
@@ -156,4 +177,125 @@ export function handleUpdateTaskLabel(project: Project, action: UpdateTaskLabel)
             }
         }
     };
+}
+
+export interface UpdateParam extends Action {
+    name: string
+    value: any
+}
+
+export const UPDATE_PARAM = "UPDATE_PARAM";
+
+export function updateParam(name: string, value: any): UpdateParam {
+    return { type: UPDATE_PARAM, name, value };
+}
+
+export function handleUpdateParam(project: Project, action: UpdateParam): Project {
+    return {
+        ...project,
+        params: {
+            ...project.params,
+            [action.name]: action.value,
+        }
+    };
+}
+
+export interface UpdateTaskCategoryLabel extends Action {
+    categoryId: TaskCategoryID
+    label: string
+}
+
+export const UPDATE_TASK_CATEGORY_LABEL = "UPDATE_TASK_CATEGORY_LABEL";
+
+export function updateTaskCategoryLabel(categoryId: TaskCategoryID, label: string): UpdateTaskCategoryLabel {
+    return { type: UPDATE_TASK_CATEGORY_LABEL, categoryId, label };
+}
+
+export function handleUpdateTaskCategoryLabel(project: Project, action: UpdateTaskCategoryLabel): Project {
+    return {
+        ...project,
+        params: {
+            ...project.params,
+            taskCategories: {
+                ...project.params.taskCategories,
+                [action.categoryId]: {
+                    ...project.params.taskCategories[action.categoryId],
+                    label: action.label
+                },
+            }
+        }
+    };
+}
+
+export interface UpdateTaskCategoryCost extends Action {
+    categoryId: TaskCategoryID
+    costPerTimeUnit: number
+}
+
+export const UPDATE_TASK_CATEGORY_COST = "UPDATE_TASK_CATEGORY_COST";
+
+export function updateTaskCategoryCost(categoryId: TaskCategoryID, costPerTimeUnit: number): UpdateTaskCategoryCost {
+    return { type: UPDATE_TASK_CATEGORY_COST, categoryId, costPerTimeUnit };
+}
+
+export function handleUpdateTaskCategoryCost(project: Project, action: UpdateTaskCategoryCost): Project {
+    return {
+        ...project,
+        params: {
+            ...project.params,
+            taskCategories: {
+                ...project.params.taskCategories,
+                [action.categoryId]: {
+                    ...project.params.taskCategories[action.categoryId],
+                    costPerTimeUnit: action.costPerTimeUnit
+                },
+            }
+        }
+    };
+}
+
+export const ADD_TASK_CATEGORY = "ADD_TASK_CATEGORY";
+
+export interface AddTaskCategory extends Action {
+    taskCategory: TaskCategory
+}
+
+export function addTaskCategory(taskCategory: TaskCategory): AddTaskCategory {
+    return { type: ADD_TASK_CATEGORY, taskCategory };
+}
+
+export function handleAddTaskCategory(project: Project, action: AddTaskCategory): Project {
+    const taskCategory = { ...action.taskCategory };
+    return {
+        ...project,
+        params: {
+            ...project.params,
+            taskCategories: {
+                ...project.params.taskCategories,
+                [taskCategory.id]: taskCategory,
+            }
+        }
+    };
+}
+
+export interface RemoveTaskCategory extends Action {
+    taskCategoryId: TaskCategoryID
+}
+
+export const REMOVE_TASK_CATEGORY = "REMOVE_TASK_CATEGORY";
+
+export function removeTaskCategory(taskCategoryId: TaskCategoryID): RemoveTaskCategory {
+    return { type: REMOVE_TASK_CATEGORY, taskCategoryId };
+}
+
+export function handleRemoveTaskCategory(project: Project, action: RemoveTaskCategory): Project {
+    const taskCategories = { ...project.params.taskCategories };
+    delete taskCategories[action.taskCategoryId];
+    return {
+        ...project,
+        params: {
+            ...project.params,
+            taskCategories
+        }
+    };
 }
\ No newline at end of file
diff --git a/src/index.js b/src/index.js
index f6dae11..10781ad 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,5 +1,6 @@
 import "./style/index.css";
 import "bulma/css/bulma.css";
+import "bulma-switch/dist/css/bulma-switch.min.css";
 
 import App from "./components/app.tsx";
 
diff --git a/src/models/params.ts b/src/models/params.ts
index bfd01da..f754757 100644
--- a/src/models/params.ts
+++ b/src/models/params.ts
@@ -1,4 +1,4 @@
-import { TaskCategory, CategoryID } from "./task";
+import { TaskCategory, TaskCategoryID } from "./task";
 import { Project } from "./project";
 
 export interface TaskCategoriesIndex {
@@ -41,6 +41,7 @@ export const defaults = {
     },
     roundUpEstimations: true,
     currency: "€ H.T.",
+    costPerTimeUnit: 500,
 }
 
 export function getTimeUnit(project: Project): TimeUnit {
@@ -57,4 +58,8 @@ export function getCurrency(project: Project): string {
 
 export function getTaskCategories(project: Project): TaskCategoriesIndex {
     return project.params.taskCategories ? project.params.taskCategories : defaults.taskCategories;
+}
+
+export function getTaskCategoryCost(taskCategory: TaskCategory): number {
+    return taskCategory.hasOwnProperty("costPerTimeUnit") ? taskCategory.costPerTimeUnit : defaults.costPerTimeUnit;
 }
\ No newline at end of file
diff --git a/src/models/project.ts b/src/models/project.ts
index 0fe4878..dbaef7c 100644
--- a/src/models/project.ts
+++ b/src/models/project.ts
@@ -24,12 +24,9 @@ export function newProject(id?: string): Project {
         tasks: {},
         params: {
             taskCategories: defaults.taskCategories,
-            currency: "€",
-            roundUpEstimations: true,
-            timeUnit: {
-                label: "Jour/homme",
-                acronym: "j/h",
-            } 
+            currency: defaults.currency,
+            roundUpEstimations: defaults.roundUpEstimations,
+            timeUnit: defaults.timeUnit,
         },
     };
 }
\ No newline at end of file
diff --git a/src/models/task.ts b/src/models/task.ts
index 3e60b1f..363ade2 100644
--- a/src/models/task.ts
+++ b/src/models/task.ts
@@ -11,19 +11,19 @@ export enum EstimationConfidence {
 export interface Task {
     id: TaskID
     label: string
-    category: CategoryID
+    category: TaskCategoryID
     estimations: { [confidence in EstimationConfidence]: number }
 }
 
-export type CategoryID = string
+export type TaskCategoryID = string
 
 export interface TaskCategory {
-    id: CategoryID
+    id: TaskCategoryID
     label: string
     costPerTimeUnit: number
 }
 
-export function newTask(label: string, category: CategoryID): Task {
+export function newTask(label: string, category: TaskCategoryID): Task {
     return {
         id: uuidV4(),
         label,
diff --git a/src/routes/project/estimation-tab.tsx b/src/routes/project/estimation-tab.tsx
index bf061be..46b16c8 100644
--- a/src/routes/project/estimation-tab.tsx
+++ b/src/routes/project/estimation-tab.tsx
@@ -49,7 +49,7 @@ const EstimationTab: FunctionalComponent<EstimationTabProps> = ({ project, dispa
                 <div class="message noPrint">
                     <div class="message-body">
                         <p><strong>⚠️ Attention</strong></p>
-                        <p>Votre projet ne contient pas assez de tâches actuellement pour que les niveaux de confiance soient fiables. Un minimum de 20 tâches est conseillé pour obtenir une estimation pertinente.</p>
+                        <p>Votre projet ne contient pas assez de tâches pour que les niveaux de confiance soient fiables. Un minimum de 20 tâches est conseillé pour obtenir une estimation pertinente.</p>
                     </div>
                 </div> :
                 null
diff --git a/src/routes/project/index.tsx b/src/routes/project/index.tsx
index 3462284..10ee68a 100644
--- a/src/routes/project/index.tsx
+++ b/src/routes/project/index.tsx
@@ -8,6 +8,7 @@ import { useLocalStorage } from "../../hooks/use-local-storage";
 import EditableText from "../../components/editable-text";
 import Tabs from "../../components/tabs";
 import EstimationTab from "./estimation-tab";
+import ParamsTab from "./params-tab";
 
 export interface ProjectProps {
     projectId: string
@@ -44,7 +45,7 @@ const Project: FunctionalComponent<ProjectProps> = ({ projectId }) => {
                         {
                             label: 'Paramètres',
                             icon: '⚙️',
-                            render: () => null
+                            render: () => <ParamsTab project={project} dispatch={dispatch} />
                         },
                         {
                             label: 'Exporter',
diff --git a/src/routes/project/params-tab.tsx b/src/routes/project/params-tab.tsx
new file mode 100644
index 0000000..2f4dd4b
--- /dev/null
+++ b/src/routes/project/params-tab.tsx
@@ -0,0 +1,79 @@
+import { FunctionalComponent, h, Fragment } from "preact";
+import { Project } from "../../models/project";
+import TaskTable from "./tasks-table";
+import TimePreview from "./time-preview";
+import FinancialPreview from "./financial-preview";
+import { addTask, updateTaskEstimation, removeTask, updateProjectLabel, updateTaskLabel, ProjectReducerActions, updateParam } from "../../hooks/use-project-reducer";
+import { getRoundUpEstimations, getCurrency, getTimeUnit } from "../../models/params";
+import TaskCategoriesTable from "./task-categories-table";
+
+export interface ParamsTabProps {
+    project: Project
+    dispatch: (action: ProjectReducerActions) => void
+}
+
+const ParamsTab: FunctionalComponent<ParamsTabProps> = ({ project, dispatch }) => {
+    const onRoundUpChange = (evt: Event) => {
+        const checked = (evt.currentTarget as HTMLInputElement).checked;
+        dispatch(updateParam("roundUpEstimations", checked));
+    };
+
+    const onCurrencyChange = (evt: Event) => {
+        const value = (evt.currentTarget as HTMLInputElement).value;
+        dispatch(updateParam("currency", value));
+    };
+
+    const timeUnit = getTimeUnit(project);
+
+    const onTimeUnitLabelChange = (evt: Event) => {
+        const value = (evt.currentTarget as HTMLInputElement).value;
+        dispatch(updateParam("timeUnit", { ...timeUnit, label: value }));
+    };
+
+    const onTimeUnitAcronymChange = (evt: Event) => {
+        const value = (evt.currentTarget as HTMLInputElement).value;
+        dispatch(updateParam("timeUnit", { ...timeUnit, acronym: value }));
+    };
+
+    return (
+        <Fragment>
+            <div class="field">
+                <input type="checkbox"
+                    id="roundUpEstimations"
+                    name="roundUpEstimations" 
+                    class="switch"
+                    onChange={onRoundUpChange}
+                    checked={getRoundUpEstimations(project)} />
+                <label for="roundUpEstimations">Arrondir les estimations de temps à l'entier supérieur</label>
+            </div>
+            <hr />
+            <div class="field">
+                <label class="label">Unité de temps</label>
+                <div class="control">
+                    <input class="input" type="text"
+                        onChange={onTimeUnitLabelChange}
+                        value={timeUnit.label} />
+                </div>
+                <label class="label">Acronyme</label>
+                <div class="control">
+                    <input class="input" type="text"
+                        onChange={onTimeUnitAcronymChange}
+                        value={timeUnit.acronym} />
+                </div>
+            </div>
+            <hr />
+            <div class="field">
+                <label class="label">Devise</label>
+                <div class="control">
+                    <input class="input" type="text"
+                        onChange={onCurrencyChange}
+                        value={getCurrency(project)} />
+                </div>
+            </div>
+            <hr />
+            <TaskCategoriesTable project={project} dispatch={dispatch} />
+        </Fragment>
+    );
+};
+
+export default ParamsTab;
diff --git a/src/routes/project/task-categories-table.tsx b/src/routes/project/task-categories-table.tsx
new file mode 100644
index 0000000..89f4935
--- /dev/null
+++ b/src/routes/project/task-categories-table.tsx
@@ -0,0 +1,70 @@
+import { FunctionalComponent, h } from "preact";
+import { Project } from "../../models/project";
+import * as style from './style.css';
+import { projectReducer, ProjectReducerActions, updateTaskCategoryCost, updateTaskCategoryLabel, removeTaskCategory } from "../../hooks/use-project-reducer";
+import EditableText from "../../components/editable-text";
+import { TaskCategoryID } from "../../models/task";
+import ProjectTimeUnit from "../../components/project-time-unit";
+import { getCurrency, getTaskCategoryCost } from "../../models/params";
+
+export interface TaskCategoriesTableProps {
+    project: Project
+    dispatch: (action: ProjectReducerActions) => void
+}
+
+const TaskCategoriesTable: FunctionalComponent<TaskCategoriesTableProps> = ({ project, dispatch }) => {
+    const onTaskCategoryRemove = (categoryId: TaskCategoryID) => {
+        dispatch(removeTaskCategory(categoryId));
+    };
+
+    const onTaskCategoryLabelChange = (categoryId: TaskCategoryID, value: string) => {
+        dispatch(updateTaskCategoryLabel(categoryId, value));
+    };
+
+    const onTaskCategoryCostChange = (categoryId: TaskCategoryID, value: string) => {
+        const cost = parseFloat(value);
+        dispatch(updateTaskCategoryCost(categoryId, cost));
+    };
+
+    return (
+        <div class="table-container">
+            <label class="label">Catégories de tâche</label>
+            <table class={`table is-bordered is-striped" ${style.middleTable}`}>
+                <thead>
+                    <tr>
+                        <th class={`${style.noBorder} is-narrow`}></th>
+                        <th>Catégorie</th>
+                        <th>Coût par unité de temps</th>
+                    </tr>
+                </thead>
+                <tbody>
+                    {
+                        Object.values(project.params.taskCategories).map(tc => {
+                            return (
+                                <tr key={`task-category-${tc.id}`}>
+                                    <td>
+                                        <button
+                                            onClick={onTaskCategoryRemove.bind(null, tc.id)}
+                                            class="button is-danger is-small is-outlined">
+                                        🗑️
+                                        </button>
+                                    </td>
+                                    <td><EditableText value={tc.label} 
+                                        onChange={onTaskCategoryLabelChange.bind(null, tc.id)} />
+                                    </td>
+                                    <td>
+                                        <EditableText value={`${getTaskCategoryCost(tc)}`}
+                                            render={value=> (<span>{value} {getCurrency(project)}</span>)}
+                                            onChange={onTaskCategoryCostChange.bind(null, tc.id)} />
+                                    </td>
+                                </tr>
+                            );
+                        })
+                    }
+                </tbody>
+            </table>
+        </div>
+    );
+};
+
+export default TaskCategoriesTable;
diff --git a/src/routes/project/tasks-table.tsx b/src/routes/project/tasks-table.tsx
index 77bc374..8de4261 100644
--- a/src/routes/project/tasks-table.tsx
+++ b/src/routes/project/tasks-table.tsx
@@ -85,7 +85,7 @@ const TaskTable: FunctionalComponent<TaskTableProps> = ({ project, onTaskAdd, on
                         <th class={`${style.noBorder} noPrint`} rowSpan={2}></th>
                         <th class={style.mainColumn} rowSpan={2}>Tâche</th>
                         <th rowSpan={2}>Catégorie</th>
-    <th colSpan={3}>Estimation (en <ProjectTimeUnit project={project} />)</th>
+                        <th colSpan={3}>Estimation (en <ProjectTimeUnit project={project} />)</th>
                     </tr>
                     <tr>
                         <th>Optimiste</th>