Making your own gi is a realistic sewing project if you have intermediate skills and the right fabric. A martial arts gi consists of three main pieces: a reinforced jacket with a thick lapel, drawstring pants, and a belt. The jacket is the most complex part, requiring durable fabric, proper reinforcement at stress points, and a collar sturdy enough to withstand grabbing. Here’s how to approach each stage from fabric selection through final assembly.
Choosing the Right Fabric
The fabric you pick determines how your gi feels, how long it lasts, and how heavy it is. Gi fabrics are measured in GSM (grams per square meter), and most range between 250 and 550 GSM. For a first build, aim for the middle of that range.
Pearl weave is the most popular fabric for Brazilian jiu-jitsu gis. It has a bumpy, textured surface that’s breathable and dries relatively fast. At 350 GSM, it’s light enough for warm-weather training and tournaments. At 450 GSM, it offers more durability while still allowing good flexibility. One thing to know: pearl weave doesn’t shrink much after washing, so your pattern measurements need to be close to final size from the start.
Gold weave has a distinct ladder pattern created by weaving heavier threads with thinner ones. It’s thick, durable, and harder to grip, which is an advantage in grappling. It was once the standard for competition gis but has become less common because of higher material costs. If you can source it, gold weave makes a very sturdy gi.
Ripstop is a lightweight, grid-patterned fabric used primarily for gi pants. It resists tearing along seam lines and holds up well under stress. Many commercial gis pair a pearl weave jacket with ripstop pants to keep the overall weight down.
For a traditional karate or judo gi, a medium-weight cotton canvas (around 400 to 500 GSM) works well for the jacket, with a lighter cotton drill for the pants. Buy 100% cotton if you want the option to shrink the finished gi in a hot wash for a tighter fit. Cotton blends with polyester resist shrinkage but also trap more heat.
Taking Measurements and Making a Pattern
You can draft a pattern from scratch using body measurements, or you can deconstruct an existing gi that fits well. If you’re tracing an old gi, take it apart at the seams, press each piece flat, and trace them onto pattern paper with a 1.5 cm seam allowance on every edge. Label each piece clearly: left front panel, right front panel, back panel, sleeves, collar strip, and knee reinforcement patches.
If you’re drafting from measurements, standard sizing gives you useful reference points. For an average adult male standing 170 to 180 cm tall and weighing 70 to 80 kg (roughly a size A2), target a chest circumference of about 103 cm and an overall jacket length of 164 cm from collar to hem. For someone 180 to 190 cm and 80 to 90 kg (size A3), chest goes up to 107 cm and length to 170 cm. Female sizing runs smaller: an F2 for someone 165 to 175 cm targets an 92 cm chest and 152 cm length.
The key measurements you need from the person wearing the gi are: shoulder width, chest circumference, arm length (shoulder to wrist), torso length (base of neck to mid-thigh), waist, hip circumference, and inseam. Add 5 to 8% to all measurements if you’re using non-preshrunk cotton, since a hot wash and tumble dry can pull cotton fabric in noticeably.
Competition Fit Requirements
If you want the gi to be legal for IBJJF competition, build to these specs: the jacket must reach the thigh, and sleeves can be no more than 2 cm above the wrist when the arm is extended straight out. The lapel needs to be at least 1.3 cm thick, the collar at least 5 cm wide, and the sleeve opening at full extension must be at least 7 cm. These minimums prevent gis from being too tight or too short, which would make gripping difficult for opponents.
Cutting the Fabric
Lay your fabric on a large, flat surface and pin each pattern piece in place. Cut with sharp fabric shears, not scissors. You’ll need the following pieces:
- Jacket back panel: one piece, cut on the fold for symmetry
- Jacket front panels: two pieces, mirror-imaged, with overlap for the lapel crossing
- Sleeves: two pieces
- Collar/lapel strip: one long strip, typically cut from the same fabric or a heavier one
- Pant legs: two pieces each for front and back, or two full pieces if using a simpler straight-leg pattern
- Reinforcement patches: knee patches, underarm gussets, and side-slit reinforcements
Before cutting, check that the fabric grain runs vertically on all major pieces. Cutting off-grain causes the finished garment to twist after washing.
Sewing the Jacket
Start by joining the back panel to the two front panels at the shoulder seams. Use a flat-felled seam (folding one seam allowance over the other and stitching it flat) for maximum strength. A standard straight stitch will fail under grappling stress, so use a flat-felled or French seam throughout, and topstitch every seam with a second row of stitching about 5 mm from the first.
Next, set the sleeves into the armholes. Pin the sleeve cap to the armhole, matching the center of the sleeve to the shoulder seam, and sew around. If you’re adding underarm gussets (diamond-shaped inserts that improve range of motion), sew them in at this stage before closing the side seams. Close the side seams from the bottom of the sleeve down to the jacket hem in one continuous line.
The collar is the most labor-intensive part. Cut a strip of heavy fabric (or fold your main fabric into multiple layers) about 5 cm wide and long enough to run from the bottom of one front panel, up around the neckline, and down the other front panel. For competition compliance, the finished collar should be at least 1.3 cm thick, which usually means folding the strip and inserting a core material like dense cotton batting or rubber foam. Pin the collar strip along the front edges and neckline, then stitch it down firmly on both the inner and outer edges.
Reinforce the areas that take the most abuse: the armpits, the side slits at the hem, and anywhere the collar meets the body of the jacket. Add bartack stitches (tight zigzag clusters) at every stress point. Commercial gis often have six to eight bartacks at the base of the collar alone.
Sewing the Pants
Gi pants are simpler than the jacket. Join the front and back pieces of each leg at the inseam, then connect the two legs at the crotch seam. Use the same flat-felled seam technique. The crotch seam gets heavy stress during kicks and guard work, so double-stitch it and add a reinforcement patch (a triangular gusset) at the intersection.
Sew knee reinforcement patches on the front of each leg between mid-thigh and mid-shin. These can be the same fabric as the pants or a heavier material. Stitch them down on all four edges and add a diagonal cross-stitch for extra hold.
For the waistband, fold the top of the pants over twice to create a channel wide enough for a drawstring. Leave a 3 cm opening at center front for the drawstring to exit. Some gi makers also add internal elastic at the back of the waistband for a more secure fit. Thread a flat cotton drawstring (about 1.5 cm wide) through the channel.
Hem the pant legs with a double fold, stitching close to the inner fold. If you’re using ripstop fabric for the pants, a single rolled hem works fine since ripstop resists fraying on its own.
Finishing and Fitting
Once both pieces are assembled, try the gi on the intended wearer before finishing the hems. Check that the jacket reaches mid-thigh, the sleeves fall within 2 cm of the wrist, and the pants sit at or just above the ankle bone. Mark any adjustments with tailor’s chalk.
If you’re using 100% cotton and the gi came out slightly large, you can shrink it by washing in hot water and tumble drying on high heat. Expect 3 to 5% shrinkage in each direction on the first wash. Pearl weave and preshrunk fabrics won’t move much, so get those measurements right before you cut.
Finish all raw edges with a serger or a zigzag stitch to prevent fraying. Give every seam a final press with a hot iron. If you want to add patches or embroidery, sew them on at this stage since it’s much easier to position them on a finished, flat garment than to work around unfinished seams.
Tools and Materials Checklist
- Fabric: 3 to 4 meters of jacket material (350 to 450 GSM pearl weave or cotton canvas), 2 to 3 meters of pant material (ripstop or lighter cotton)
- Thread: heavy-duty polyester thread (size 40 or thicker), in a matching color
- Sewing machine: a standard home machine can handle gi fabric, but use a size 16 or 18 needle designed for heavy wovens
- Collar core: dense cotton batting, rubber foam strip, or multiple folded layers of fabric
- Drawstring: flat woven cotton cord, about 150 cm long
- Notions: pattern paper, tailor’s chalk, fabric shears, pins, measuring tape, seam ripper
A walking foot attachment for your sewing machine makes a significant difference when stitching through multiple layers of heavy fabric. Without one, the top layer tends to creep forward, causing puckering along the collar and knee patches.