Sew-In Hair Calculator
Find out exactly how many bundles you need, what length to buy, and what to budget before you book your appointment.
What kind of sew-in are you getting?
The install style determines how many weft rows fit and how much leave-out affects total coverage.
What finished length are you going for?
Bundle length and finished length are not the same. A 20-inch bundle on a 14-inch installed length is common because curly or wavy textures shrink 2 to 4 inches after installation.
What hair texture are you using?
Curly and kinky textures need more bundles per inch of coverage because each weft takes up more vertical space on the track row.
How full do you want the finished style to look?
Density is about how thick the overall style feels, not just the bundle weight. A natural look uses less hair; a full glam look needs more weft rows sewn closer together.
How many tracks does your stylist typically lay?
Most stylists sew 6 to 10 weft rows on a standard braid pattern. Fewer rows means each bundle covers more area; more rows gives seamless layering but uses more hair.
What type of hair are you buying?
Human hair bundles run 50 to 150 grams each on average, so the per-bundle price ranges widely. Synthetic wefts cost far less but cannot be heat styled above 250F and typically last 2 to 4 months with regular wear.
What is your total hair budget for this install?
This is just for the hair itself, not the install service fee. The calculator uses your budget to flag whether your bundle count fits comfortably, is tight, or may need a trade-off.
Enter any number between $10 and $5000.
What this means for your install
Shop hair matched to your result.
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Why the Bundle Count Matters More Than You Think
The single most common mistake people make before a sew-in appointment is buying hair based on a number they heard from a friend or saw on a social media post without accounting for their own head size, desired length, texture shrinkage, or how their stylist actually lays a braid pattern. Arriving at the salon with two bundles when you actually need four means one of two things: your stylist has to send you to a beauty supply store mid-appointment, or the finished style has thin, gappy sections you will be looking at for the next six to ten weeks.
A full sew-in on a medium head size at 20 inches in body wave typically uses 3 to 4 bundles, but add a vixen pattern, increase to deep wave, and push the density to full volume, and you are at 5 to 6 bundles. That is a $150 to $300 difference depending on hair grade. This calculator accounts for each of those variables separately so the estimate you get reflects your specific choices rather than a one-size-fits-all guess. Before purchasing multiple packs, you can also consult our bundle length mix calculator to figure out how to blend different sizes for a natural look.
How Bundle Weight Actually Works
Bundles are sold by weight, typically 100 grams, but the weight tells you how much raw hair is in the bundle, not how much coverage you get. A 100-gram straight bundle fans out across a wider area than a 100-gram kinky bundle, because the kinky bundle is coiled up and takes up more vertical space per weft row. This is why curly and kinky textures consistently require one to two more bundles than straight textures at the same stated length, a fact that surprises buyers every time until they understand the geometry.
Bundle Count Reference by Length and Texture
| Finished Length | Straight / Yaki | Body Wave | Deep Wave / Curly | Kinky / Afro Curl |
|---|---|---|---|---|
| Short (up to 12 in) | 2 bundles | 2 bundles | 3 bundles | 3 bundles |
| Medium (14 to 18 in) | 3 bundles | 3 bundles | 3 to 4 bundles | 4 bundles |
| Long (20 to 24 in) | 3 to 4 bundles | 3 to 4 bundles | 4 to 5 bundles | 4 to 5 bundles |
| Extra Long (26 in+) | 4 to 5 bundles | 4 to 5 bundles | 5 to 6 bundles | 5 to 6 bundles |
Counts assume a standard 8 to 9 row braid pattern and medium density. Add one bundle for a vixen install or for full volume density. Subtract one bundle for a partial sew-in at short to medium lengths.
Comparing Sew-In Hair Types
Virgin Human Hair
Unprocessed, cuticle-aligned hair with all cuticles running in the same direction. Accepts color and heat without the matting or tangling that processed hair develops. Price per bundle at 18 inches runs $80 to $150 or more from reputable suppliers.
Remy Human Hair
Cuticle-aligned but may have undergone light color or texture processing. The most popular mid-market choice for sew-ins. At 18 inches, expect $45 to $80 per bundle. Lasts 1 to 2 years with proper maintenance before the shafts begin to thin.
Non-Remy Human Hair
Cuticles stripped through acid washing, then a silicone coating applied to fake smoothness. Looks great out of the bag, begins to tangle and mat within 4 to 8 weeks. Best used for one or two install cycles. Budget pick at $20 to $40 per bundle.
Synthetic Fiber
The lowest per-bundle cost ($10 to $25), but most synthetic wefts cannot handle direct heat above 250 to 350 degrees Fahrenheit. Lasts 2 to 4 months with regular wear. Heat-resistant (also called heat-friendly) fiber handles up to 350F but still does not behave like human hair under styling tools.
Ready to shop Remy bundles in your chosen texture? This search returns a broad selection across price points so you can compare before buying.
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Special Situations Your Stylist Will Ask About
Mixing Bundle Lengths
Most experienced stylists use two or three different bundle lengths in a single install rather than buying all bundles in one length. A common combination for a 20-inch finished look is two 22-inch bundles sewn at the crown and two 20-inch bundles sewn in the middle rows, with one 18-inch bundle used at the lower nape rows where the hair sits closer to the head anyway. This layering creates a more realistic, gradual density that mimics how natural hair grows rather than every strand hitting the same point at the same length.
Vixen Installs and the Extra Bundle Rule
A vixen sew-in divides the scalp into four braid sections separated by leave-out parts running from ear to ear and front to back. Because each section is treated as its own install zone, you need enough hair in each section to cover independently. Many stylists add one to two extra bundles beyond a standard full sew-in count for this reason. If you plan to wear the hair parted frequently in different directions, this is not optional: the sections need to be full enough to not expose the braids underneath when the hair shifts.
Fine or Thin Natural Hair Under the Braids
If your natural hair is fine or has significant thinning, the braid base will be flatter and closer to the scalp, which means track rows can be spaced slightly tighter, which in turn means you fit more rows in the same head space. More rows typically means one additional bundle to avoid thin spots between rows. Let your stylist know about your natural hair density before they calculate the braid pattern so the install accounts for it from the start.
Closures and Frontals Change the Bundle Math
If you add a lace closure (typically a 4x4 or 5x5 inch piece) or a frontal (13x4 or 13x6 inches) at the part or hairline, you cover that area with the lace piece rather than a sewn weft. This reduces the number of bundles needed for the rest of the head by roughly one bundle compared to a bare scalp full sew-in. A closure or frontal gives you a clean part without leaving out any natural hair, but it is a separate purchase that typically costs $50 to $200 and is not included in the bundle count this calculator produces.
Shrinkage and Buying Longer Than You Think You Need
This is the issue that generates the most complaints after an install. A client who wanted 16-inch shoulder-length hair buys 16-inch bundles in deep wave, the stylist installs them, and after the first wash the hair sits at 12 inches. That is not a defective product. Deep wave and curly textures shrink 2 to 5 inches in their natural wet state. If you want a specific finished length in a wavy or curly texture, buy bundles that are 2 to 4 inches longer than your target and confirm with your stylist before ordering. To verify how your chosen inches will look on your frame, you can check our hair extension length calculator.
Frequently Asked Questions
How many bundles do I need for a full sew-in at 18 inches with body wave hair?
For a full sew-in at an 18-inch finished length with body wave texture, most installs use 3 bundles for natural to medium density. If you want a fuller, thicker finish or your stylist lays more than 9 rows, bring 4 bundles. The extra bundle is insurance: it is easier to return an unopened bundle than to scramble for a match mid-appointment.
Does the number of bundles change if I have a big head?
Yes, head circumference affects coverage. The average adult head circumference is about 22 inches. If yours measures 23 inches or more, you will likely need one additional bundle at any length because each weft row has more perimeter to cover. Most bundle count guides, including this calculator, target the average. Tell your stylist your head measurements if you know them and ask whether they factor that into their estimate.
Can I buy all my bundles in the same length to save money?
You can, and many people do, but the result looks less natural. When every strand terminates at exactly the same point, the ends look blunt and heavy in a way that real hair simply does not. Buying two lengths, for example 18 and 20 inches instead of three 20-inch bundles, creates visual variation that reads as more believable. The cost difference is usually minimal and the result is noticeably better.
What is the difference between a 3-bundle and a 4-bundle deal, and should I always buy deals?
Bundle deals bundle (pun intended) multiple packs together at a per-bundle discount. A 3-bundle deal at a given length is priced lower per piece than buying three individual bundles separately. The catch is that you need to want all three in the same texture and length, which is not always what your install requires. If your stylist recommends mixing lengths, a single-length deal saves you money on the paper but leaves you with hair that is the wrong length for part of the install.
How long does a sew-in install typically last, and how does that affect cost per wear?
A well-maintained sew-in with quality Remy human hair lasts 6 to 10 weeks before the braid base needs to be taken down and redone to protect your natural hair. Some clients push to 12 weeks, though most stylists do not recommend it. If your hair cost $200 and the install lasts 8 weeks, that is about $25 per week for your hair, not counting the install service fee. At 6 weeks, it is just over $33 per week. This framing helps compare the cost of a sew-in to a wig or to clip-in extensions over the same period. If you want to plan for ongoing upkeep expenses, you can review our extension maintenance calculator to budget accordingly.
Why does the stated bundle length not match where the hair actually falls on my body?
Bundle length is measured from the weft (the sewn top) to the tip when the hair is stretched straight. On your head, the hair does not start at the top of your skull; it starts at whichever row the weft is sewn onto, which is several inches down from your crown. Additionally, body wave and curly textures contract when they are not being held straight. Both factors mean a 20-inch bundle on an actual person at a medium height with an average shoulder width will fall somewhere between mid-back and bra-strap depending on where it is sewn and what the texture does after installation.
Is it better to buy an extra bundle and have leftovers, or buy exactly what I think I need?
Buy one extra bundle. Every experienced stylist says the same thing. The cost of an extra bundle is almost always less than the cost of an emergency same-day run to find a matching bundle from a different vendor. Bundles from different lots, even the same brand, can vary in shade, texture, and weight enough to create a visible mismatch. Keep the extra bundle unopened and return it if you do not need it. If you open it, keep it for repairs or quick touch-up pieces between full installs.
Do I need a closure or frontal in addition to my bundles?
Not necessarily, but most people find the hairline looks cleaner with one. A closure or frontal covers the top portion of the head and the part area so you do not need to leave out any natural hair to create a realistic hairline. Without one, you either leave out your own edges (which requires heat blending) or the top of the install has visible track rows near the part. Budget an additional $60 to $180 for a quality lace closure that matches your bundle texture, and confirm with your stylist which size they prefer to work with before you order.
For most clients getting their first or second sew-in, a 3-bundle set of Remy body wave in 18 to 20 inches is the most versatile starting point. It covers the most common installs, blends well with a wide range of natural textures, and is easy to find in consistent quality across multiple vendors.
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This page contains affiliate links. As an Amazon Associate I earn from qualifying purchases at no additional cost to you. Bundle count estimates and price ranges are based on industry averages and are provided for planning purposes only. Actual requirements vary based on head size, stylist technique, and product specifications. If you are comparing installation methods, you might also find our hair extension budget calculator helpful for analyzing total upfront and long-term costs.