Short answer: No. Baking soda and baking powder are not the same, though they are both leavening agents used to help baked goods rise. What they are

• Baking soda: Pure sodium bicarbonate. It needs an acid and moisture to activate. When activated, it produces carbon dioxide that leavens the dough or batter. It acts quickly, so recipes using it often bake immediately after mixing.
• Baking powder: A complete leavening agent that already contains sodium bicarbonate and an acid (often cream of tartar) plus a buffering starch. It usually works in two stages (especially the common double-acting variety): some rise at room temperature when mixed with liquid, and more rise during baking when heated.

Key differences and practical tips

• Activation: Baking soda requires an acidic ingredient (like yogurt, buttermilk, lemon juice, brown sugar, molasses, or chocolate) to activate. Baking powder contains its own acid, so it can leaven baked goods with little or no additional acidic components.
• Strength and substitutions: Baking soda is about 3–4 times stronger than baking powder by weight. Substituting one for the other usually requires adjusting amounts and possibly adding or removing acidic ingredients, which can affect flavor and texture.
• Flavor and browning: Using baking soda can promote browning and a more quickly rising batter, but too much can lead to a soapy or metallic taste. Baking powder tends to produce a moister, lighter crumb with less risk of overwhelming alkaline flavors.
• When to use which:
  • Use baking soda when the recipe includes an acidic component and you want a quick lift.
  • Use baking powder when there is little or no acid in the recipe, or you want a more controlled, longer-lasting rise (often via double-acting powder).

Common substitutions (with caveats)

• If you only have baking powder and a recipe calls for baking soda: you can replace 1 teaspoon of baking soda with 3 teaspoons of baking powder, but you should reduce or adjust any acidic ingredients to balance flavor; the result may be slightly different in texture and flavor.
• If you only have baking soda and a recipe calls for baking powder: you’d need to add an acid (like cream of tartar) to activate the baking soda, but this can change flavor and moisture; generally, it’s best to find a recipe that matches the leavening you have.

Bottom line: They are not interchangeable, but with careful adjustments you can achieve similar results in some cases. If you share a specific recipe or bake you’re working on, the adjustments can be tailored precisely.